Quiz 1 Epidemiology, Quiz 2: Chapters 5, 6, 7 & 8
What is a community intervention and program evaluation?
another type of experimental design using quasi-experimental design. A community intervention (community trial) is an intervention designed for the purpose of educational and behavioral changes at the population level
A ______________ is a specific type of categorical (discrete) variables that only have 2 possible levels or categories.
dichotomous variables
What do you do when you are trying to find the median and you have an odd number of scores?
find the average of the two median scores
The extent to which a piece of evidence supports a claim about the cause and effect within the context of a particular study is ____________________.
internal validity
What are three examples of specific rates?
Cause-specific rates Age-specific rates Sex-specific rates
The _____________ is the average difference between observed data points and the mean.
Mean deviation
If age is a confounding variable, how can it be controled?
only use one age group
Always keep an ________________ when evaluating evidence from epidemiologic studies.
open mind
What does the confounding variable do?
Causes confusion of effects that is a nuisance and should be controlled for if possible Example: Age and smoking are often confounders
What are the five measures of disease occurrence related to morbidity and mortality?
1 Crude rates 2 Case-fatality rates 3 Proportional mortality ratio 4 Cause-specific rates 5 Adjusted rates
What are the Core Public Health Functions Steering Committee developed a framework for essential services?
1- Three core functions of public health: Assurance, Assessment, Policy Development 2- Ten essential public health services: monitor health; diagnose and investigate; inform, educate, empower; mobilize community partnership; develop policies; enforce laws; link to/provide care; assure competent workforce; evaluate; research
In a standard normal distribution a z-score of zero would correspond to the ___________________.
50th percentile
A sample mean of ± 1.96 SEM gives the ______ confidence interval around the mean in the population.
95%
2 standard deviations is equal to the ______________ percentile.
95.5% of data
A sample mean of ± 2.58 SEM gives the ______ confidence interval around the mean in the population.
99%
What is a randomized controlled trial? (RCT)
A clinical-epidemiological experiment in which subjects are randomly allocated into groups, usually called test and control groups, to receive or not to receive a preventive or a therapeutic procedure or intervention
According to Hill's criteria of causality, what is biological gradient?
A dose-response curve shows a linear trend in the association between exposure and disease
What is a clinical trial?
A research activity that involves the administration of a test regimen to humans to evaluate its efficacy and safety
What is the method of concomitant variation?
A type of association in which the frequency of an outcome increases with the frequency of the exposure to a factor
_________________ is the group of people within the target population that are available to the researcher.
Accessible population
When discussing ethics in research it refers to ___________________.
Adherence to ethical norms
An _________________ of morbidity or mortality in a population in which statistical procedures have been applied to permit fair comparisons across populations
Adjusted rates
What are the limitations to birth statistics?
Affected by mother's failure to recall events during pregnancy May miss conditions that were not detected at birth
Assessment of exposure is imprecise in many studies, as is the delineation of the mechanisms that connect exposure to outcome. A.B. Hill raised the question of how one moves from an observed association to the verdict of causation?
After a clear association is found via statistical analysis (association is not due to chance)
What are person variables?
Age Sex Race/ethnicity Socioeconomic status Marital status Nativity (place of origin) Migration Religion
Epidemiologic studies have shown morbidity and mortality sex differences in a wide scope of health phenomena. What are some examples?
All-cause age-specific mortality rates are higher among males. In developed countries, life expectancy is higher in females then males. Principally due to lower heart disease mortality among females. Some chronic diseases occur more frequently in women (depression, lupus)
How do epidemiologists assert statistical significance?
Assertion that an observed association is not likely to have occurred as a result of chance, generally significance is p=0.05 or less
What is the framingham heart study?
Assess the relationship between dairy consumption & changes in systolic & diastolic BP
_____ involves the likelihood of experiencing an adverse effect
Risk
__________________ is a linkage between or among variables.
Association
What are some examples of determinate?
Biologic agents Smoking Obesity
A ____________ is a qualitative type of graph that shows the frequency of cases for categories of a discrete variable.
Bar chart
What are types of graphs used?
Bar chart Line graph Pie chart
A retrospective cohort study is different from a case-control study?
Because in a retrospective cohort study an entire cohort of exposed individuals is examined - In a case-control study there are a limited number of cases and controls that usually do not represent an entire cohort of individuals
What are cost-effectiveness (CE) ratios used for?
CE ratios are compared for alternative programs and interventions to identify the least costly alternatives Facilitates the optimization of resources for public health programs
Where can I find more information on the framingham heart study, a prospective cohort study example?
Chapter 7 slides 64 through 72
What are some frequent issues with denominators in incidence and prevalence measures?
Classification of population subgroups may be ambiguous (e.g., race/ethnicity) It is often difficult to identify and remove from the denominator persons not "at risk" of developing the disease (e.g., people who are immune)
___________________ selects participants through randomly within an area that is divided into geographical clusters are selected for inclusion.
Cluster sampling
___________ is a closely grouped series of events or cases of a disease or other health-related phenomena with well-defined distribution patterns in relation to time or place or both.
Clustering
The ____________ is the long-term variation in disease occurrence among a group of persons who share something in common.
Cohort effects
What is National Health and Nutrition Examination Survey (NHANES) data?
Collection of information from physical examinations coupled with interviews
What can clustering reflect?
Common exposure to an etiologic agent Chance occurrences
______ is the probability that an event will occur.
Risk
What are descriptive epidemiological studies concerned with?
Concerned with characterizing the amount and distribution of health and disease within a population To identify health problems and patterns of disease that exist
____________ are also known as dimensional, quantitative, interval variables and measured on a scale that has a smooth transition across all possible values (values fall along a continuum that can include decimals - tenths, hundredths, etc).
Continuous variables
What is one type of non-probability sampling that uses participants selected because they have characteristics of interest & are easy to reach?
Convenience sampling or grab-bag sampling
What is the correlation coefficient?
Correlation coefficient (denoted as r) Range of r is from -1.0 to 1.0 r evaluated in relation to difference from 0
____________ are used to describe the strength & direction of a relationship between two variables (bivariate correlation) and indicates the degree to which two variables are related to each other.
Correlations
__________ is the simplest and most frequently used measure in epidemiology that refers to the number of cases of a disease or other health phenomenon being studied.
Counts
What is National Health Interview Survey (NHIS) data used for?
Data from the NHIS are used for monitoring how well the nation is progressing toward specific health objectives
_____________ is used to join data elements contained in data bases by trying them together with a common identifier.
Data linkage
What are factors that cause prevalence to decrease?
Decrease in incidence Shorter duration of disease In-migration of healthy people Improved cure rate of disease
What is population risk difference?
Defined as the difference in disease (outcome) between the overall rate in the population and the rate in the non-exposed segment of the population
How can proportions be misleading?
Depending on the size of the denominator: small denominator means the proportion is less meaningful than if it was a large denominator
What is the dose-response relationship?
Describes the magnitude of the response of an organism as a function of dose (exposure) to a stimulus or stressor after a certain exposure time
Urban & rural sections of the US show variations in morbidity and mortality related to environmental and lifestyle issues Examples include:
Diet Physical activity Housing conditions (i.e., lead paint) Crowding (i.e., spread of infection) Pollution
What is an example of method of difference?
Differences in coronary heart disease rates between sedentary and non-sedentary workers might be due to differences in physical activity levels
What is selection bias?
Distortions that result from procedures used to select subjects and from factors that influence participation in the study
_____________ is the occurrence of diseases and other health outcomes varies in populations affecting some subgroups of the populations are more frequently than others.
Distribution
What is the purpose of filing a case report?
Document unusual occurrences Can provide clues in identification of a new disease or adverse effects of exposures
What are the major categories of analytic designs?
Ecologic Case-control Cohort Intervention studies (Experimental designs)
What are the disadvantages of ecologic studies?
Ecologic fallacy. Imprecise measurement of exposure. Cannot link exposure to disease at the individual level. Use average exposure levels rather than actual levels of exposure. Inability to control for confounding factors.
_______________ is related to the strength of the association between exposure and outcome.
Effect size
________________ is concerned with the distribution and determinants of health and diseases.
Epidemiology
According to Hill's criteria of causality, what is experiment?
Evidence from experiments ex., public health interventions, can help support the existence of a causal relationship. Hill stated that this is the strongest form of support for a causal association
T/F Incidence and prevalence are not interrelated concepts.
False
T/F You can prove a hypothesis.
False
Nativity refers to the place of origin of the individual or his or her relatives divided between.
Foreign-born Native-born
__________ protects personal information contained in health records and data banks that collect information from surveys may release epidemiologic data as long as individuals cannot be identified.
HIPPA
_____________ is a state of complete physical, mental, and social well-being not merely the absence of disease or infirmity.
Health
What is deterministic causality?
If X, then always Y. No room for exceptions
The odds ratio is 1. What does this mean?
Indicates no association between exposure and outcome
The sixth characteristics of study designs are to determine the unit of observation. What does this mean when dealing with an observational study or an experimental study?
Individual- Most epidemiologic studies Entire group- Ecologic study
Who are policy actors?
Individuals who are involved in policy formulation Include members of the legislature, citizens, lobbyists, and representatives of advocacy groups
Who are stakeholders?
Individuals, department, families, community, law enforcement- Individuals, organizations, and members of government who are affected by policy decision
________________ is the number of infant deaths among infants age 0-365 days during a year divided by the number of live births during the same year (expressed as rate per 1,000 live births).
Infant mortality rate
What health scares liked to epidemiologic topics command our attention?
Infectious disease epidemics, Chronic disease epidemics, Behaviorally associated conditions
____________ is the process of passing from observations and axioms (statements regarded as being true) to legitimate generalizations.
Inference
The fifth characteristics of study designs are to determine the timing of data collection. What does this mean when dealing with an observational study or an experimental study?
Information obtained about past exposures- Concern about the reliability of the data Retrospective cohort or case-control study Subjects followed prospectively- Concerns about drop-out Prospective cohort or intervention study
What does an odds ratio calculate?
Instead the risk of an outcome associated with exposure is estimated by calculating the odds of exposure among the cases and controls- what are the odds of disease development
__________________ of sample is the degree to which actual sample represents intended sample.
Internal validity
What is an ecologic comparison study?
Involves an assessment of the association between exposure & disease rates during the same time period Correlation does not equal causation
Who innovated several of the key epidemiological methods that remain valid and in use today and what did they study?
John Snow, he believed that cholera was transmitted through contaminated water and demonstrated the associate through tracing water company source locations and mapping the houses/locations of disease.
Who is John Graunt?
Known as the Columbus of Statistics he was the first to employ quantitative methods in describing population vital statistics by studying the statistics available on births and deaths (1620-1674) Renaissance
What is the association of power when attempting to make an inference?
Larger samples are more likely to produce significant results With a small sample, harder to find an association
_________ refers to the time period between initial exposure and a measurable response.
Latency
What health policies are linked with the development of laws?
Licensing (e.g., licensing medical practitioners) Setting standards (e.g., specifying the allowable levels of contaminants in foods) Controlling risk (e.g., requiring the use of child safety seats) Monitoring (e.g., surveillance of infectious diseases)
A ______________ is used to display trends such as time trends.
Line graph
_______________ encompasses maternal deaths that result from causes associated with pregnancy.
Maternal mortality
What are the measures of natality (birth rate) and mortality linked to natality?
Maternal mortality rate Infant mortality rate Fetal mortality Fetal death rate Late fetal death rate Birth rate (e.g., crude birth rate) General fertility rate Perinatal mortality rate
Epidemiology is an interdisciplinary science, meaning it uses information from many fields to promote public health including...
Mathematics and biostatistics History Sociology Demography and geography Behavioral sciences Health sciences (including Nutrition) Law
When are ecologic studies used?
May be used when individual measurements are not available, but group-level data can be obtained Data usually has been previously collected
How is variance calculated?
Measures the extent to which values in a data set vary -subtract each individual value from the mean for the group -Square each result -Add results -Divide the sum of the squares by the number of values minus one to get an average of the squared variations from the mean
What might be hypothesized in a method of concomitant variation?
Might hypothesized that a particular factor is associated with that outcome (the "cause" of the outcome)
_______________ ______________ are naturally occurring circumstances in which subsets of the population have different levels of exposure to a hypothesized causal factor in a situation resembling an actual experiment.
Natural experiments
What is the negative correlation?
Negative, inverse (-) values: as values of one variable increase, values of other variable decrease
What are possible factors that would be involved in the sufficient component model for Type II DM?
Neither- Excessive sugar consumption may or may not be present for individuals who develop Type II DM; Other factors- diet, genetic predisposition- necessary?, exercise, access to health care, poverty, SES
What is the null hypothesis (H)? Ex?
No difference or no relationship in the population parameters based on the sample statistics; Ex. The hypothesis that there is no difference between smokers and nonsmokers in the occurrence of lung cancer.
According to Hill's criteria of causality, what are the contradictions to the Strength criteria that state strong associations give support to a causal relationship between exposure and disease?
Non-casual strong associations are common, for example Non-causal relation between birth rank/maternal age and Down syndrome, and strength may be comparatively small for common exposures and diseases (e.g. smoking and cardiovascular disease)
What type of sampling is prone to sampling bias and may create non-representative samples.
Nonrandom non- probability sampling
What are the limitations of prospective cohort studies?
Not efficient for the examination of rare diseases as subjects must be disease-free at the start of the study. Can be very costly and time consuming. Often requires a large sample size. Losses to follow-up can affect validity of results If large (e.g. > 30%), validity of study results may be severely compromised. Changes over time in diagnostic methods may lead to biased results.
What are the weaknesses of a retrospective cohort study?
Not useful for study of emerging, new exposures Reliance on existing records or subject recall may be less accurate and complete than data collected prospectively Records may not have been recorded for the outcome of interest Information on potential confounding factors is often unavailable from existing records
What is the meaning of the numerator and denominator in a rate?
Numerator: Number of health outcomes (disease frequency) Denominator: Population in which health outcomes occur
The first characteristic of study designs is to understand who manipulates the exposure factor. What does this mean when dealing with an observational study or an experimental study?
Observational study: exposure is not manipulated by the epidemiologist; Experimental: exposure is manipulated by the epidemiologist
_________ indicates the probability that the observed findings could have occurred by chance alone.
P-value
What is the prevalence ratio (PR) equation?
PR= a/(a+b)/ c/ (c+d)
____________ is the value of the population.
Parameter
What are the sources of data for case-control studies?
Patients from hospitals, clinics, medical practices, disease registries, advertisements on-line or newspapers
A __________ is a circular chart that shows the proportion of cases according to several categories proportional to the frequency of cases.
Pie chart
What is the purpose of prevalence measures?
Prevalence measures are used to describe the scope and distribution of health outcomes in the population
___________ have the most scientifically rigorous study design, highest level of validity for making etiologic inferences, and can control for many of the factors that affect study designs.
Randomized Control Trial
RCT stands for
Randomized controlled trial
What are examples of experimental studies?
Randomized controlled trial (RCT) Quasi-experiments
The __________ is difference between the largest (maximum value) and smallest (minimum value) scores.
Range
What are secular trends?
Refer to gradual changes in the frequency of disease over long time periods (decades)
What is external validity?
Refers to one's ability to generalize from the results of the study to an external population
What is internal validity?
Refers to the degree to which the study has used methodologically sound procedures
What is the policy cycle?
Refers to the distinct phases involved in the policy-making process
____ ____________ is a methodology used to provide quantitative measurements of risk to health
Risk assessment
________________refers to a process for identifying adverse consequences and their associated probability
Risk assessment
What are the time variables that shows that the occurrence of health-related events can vary by time?
Secular (long-term) trends Cyclic (seasonal) trends Point epidemics Cohort effects Clustering
What is reporting bias?
Selective suppression or revealing of information such as past history of sexually transmitted disease. often occurs because of reluctance to report
The _______________ is the frequency of a disease in a gender group divided by the total number of persons within that gender group during a time period times a multiplier
Sex-specific rate
________________ selects participants through randomly allowing each person a change of being selected.
Simple random sampling
What are the four types of probability sampling in which each person in the population has an equal probability or chance of being selected?
Simple random sampling (table of random numbers or online random sample generator); Systematic random sampling (random start point then choose every nth person); Stratified random sampling (divide accessible population into groups and then use #1 or #2); Multistage or Cluster random sampling (divide population, usually by geographic area, into groups, and then randomly sample within each cluster)
What are the other types of clustering?
Spatial clustering: The aggregation of events in a geographic region Temporal clustering: The occurrence of events related to time
What are some examples of multivariate or multiple causality?
Specific exposures (e.g., smoking) Family history Lifestyle characteristics Environmental influences
The _______________ is a measure of how well the mean represents the data.
Standard Deviation
What are statements of objectives?
Statements of an environmental policy intended to be assessed using information from a monitoring program that must be adequate in its quality and quantity of data so that the environmental objectives can be assessed
_______________ is the corresponding value from the sample.
Statistic
According to Hill's criteria of causality, what is strength?
Strong associations give support to a causal relationship between exposure and disease, Statistically= r values
What are case-control studies?
Subjects are defined on the basis of the presence (cases) or absence (controls) of an outcome of interest
_____________________ is a set of minimal conditions that inevitably produce disease.
Sufficient Cause Complex
________________ is the entire group in which the results of the study apply.
Target Population
According to Hill's criteria of causality, what is plausibility?
The association must be biologically plausible from the standpoint of contemporary biological knowledge
According to Hill's criteria of causality, what is temporality? example?
The cause must be observed before the effect ex. lifestyle factors are likely to be altered after the first symptoms of a disease occur
According to Hill's criteria of causality, what is coherence?
The cause-and-effect interpretation of the data should not seriously conflict with the generally known facts of the natural history and biology of the disease
The odds ratio is less than 1 (<1). What does this mean?
The exposure might be a protective factor. (folate and NTD)
What is a dose-responce assessment?
The measurement of the relationship between the amount of exposure and the occurrence of the unwanted health effects
How is a prospective cohort study created?
The researchers identify the population, recruit participants (the sample) representative of the target population, take baseline measurements, and continue to measure exposure and outcome into the future.
What is internal validity?
The results of an observation are correct for the particular group being studied Was the study done well/correctly?
What is the community use of epidemiology?
To diagnose the health of the community and the condition of the people and measure the true dimensions and distribution of ill-health looking at incidence, prevalence, disability and mortality
T/ F Remarkable variation exists in rates of disease occurrence across racial and ethnic groups.
True
T/F The presence of a valid statistical association does not imply causality.
True, A judgment of causality must be made in the presence of all available information, and reevaluated with each new finding
T/F Epidemiology is an observational science.
True, It capitalizes on naturally occurring situations in order to study the occurrence of disease.
T/F Internal validity should never be compromised in an attempt to achieve generalizability.
True, garbage in garbage out, only good studies can be generalized.
T/F The specified cause of death is not always entirely accurate.
True; because of inconsistent diagnostic criteria and/or unreported due to stigma such as HIV infection, alcoholism
What is a confidence interval?
Values for the population that the sample represents
What organization removed trans fats from processed foods?
U.S Food and Drug Administration
What are ecologic studies used for?
Used to describe disease & to postulate causal associations; correlation is not causation
What is the statistic used to estimate?
Used to estimate the population value (parameter)
How do you calculate the risk of outcome?
[(odds ratio-1) *100]= the risk of getting the disease (becoming a case, instead of control)
For which of the following criteria do epidemiologists need to observe the cause before the effect? a. Temporality b. Consistency c. Biological gradient d. Coherence
a. Temporality
What is risk management?
actions taken to control exposures to toxic chemicals in the environment oriented toward specific actions
What is the most important factor to consider when describing occurrence of disease or illness?
age
What is the public health policy National Prevention Strategy?
aims to guide our nation in the most effective and achievable means for improving health and well-being by prioritizes prevention by integrating recommendations and actions across multiple settings to improve health and save lives.
Descriptive epidemiology is concerned with culminating the hypothesis while _________________________ is concerned with testing hypotheses.
analytic epidemiology
Descriptive epidemiologic studies aid in generating hypotheses that can be explored by ____________________________________.
analytic epidemiologic studies.
What are the nationally notifiable diseases and conditions?
anthrax, botulism, gonorrhea, Hep A, B, C, HIV, AIDS, HIV/AIDS, meningococcal disease, mumps, syphilis, TB, Ebola, Zika, Covid-19
Randomized Control Trials can control for many of the factors that affect study designs. What factors are controlled?
assignment of exposures and bias in assessment of study outcomes
Epidemiologic studies may be impacted by ______.
bias
What are examples of common characteristics in a cohort study?
birth or age cohort, work cohort, school/educational cohort
What is a double-blind study?
both subjects and the experimenter do not know who has been assigned to which group in order to prevent bias
What are the four quantitate measures of health status?
counts, ratios, proportions, rates
In a ______________, participants may be switched between treatment groups.
crossover design
The epidemiologic transition coincides with the _________________________ _____________.
demographic transition
In probability causality, the probability of an event or adverse health outcome is ____________________________________________.
described in mathematical terms, given a particular dose (level of exposure).
An ______________ is "[a] graphic plotting of the distribution of cases by time of onset." and is useful in identifying the cause of a disease outbreak.
epidemic curve
What models are used to depict multivariate or multiple causality?
epidemiologic triangle and web of causation
Why research ethically?
ethical research: Promotes the aims of research (knowledge, truth, and avoidance of error) Promotes values that are essential to collaborative work (trust, accountability, mutual respect, and fairness) Helps to ensure that researchers can be held accountable to the public Helps build public support for research Promotes a variety of other important moral and social values (social responsibility, human rights, animal welfare, compliance with the law, and health and safety)
What does the odds ratio compare?
events with nonevents, the presence to the absence of an exposure given that we already know about a specific outcome
According to Hill, What is the strongest form of support for a causal association?
experiment
All of the above-mentioned person variables lead to differences in the occurrence of diseases and adverse health conditions in the population called ___________________.
health disparities
What health and disease determinate are included in epidemiology?
morbidity, injuries, disability, and mortality in populations, the control of health problems in populations
What is the equation for cause-specific rate?
mortality or frequency of a give disease/ population size at midpoint of time period *100,000
A variable measured on the _________________ consists of named mutually exclusive categories (not necessarily exhaustive), with no implied order.
nominal scale
A _____________ is a natural variation of many variables tends to follow a bell-shaped distribution.
normal distribution
A statistically significant association may merely be the result of a large sample and therefore, __________________________.
not relevant or clinically significant
All possible results that may stem from exposure to a causal factor are ________________ that are expressed as measures of morbidity and mortality.
outcomes
According to Hill's criteria of causality, what are the contradictions to plausibility?
plausibility is often based on prior beliefs rather than logic or actual data, what is considered biologically plausible at any given time depends on the current state of knowledge (they used to believe in spontaneous generation)
A ________________ refers to increased disease occurrence among a group of people exposed almost simultaneously to an etiologic factor.
point epidemic
The confidence interval is used as an alternative to __________________.
point estimate
Most community interventions used a _____________________________.
quasi-experimental designs
A ___________________ is a type of research in which the investigator manipulates the study factor.
quasi-experimental study
Any systematic error that arises in the process of identifying the study populations (i.e., the two 2 study groups to be compared) causes _______________.
selection bias
The closer the data points are on a scatter plot diagram in respect to the straight line of best fit, the _______________________________________.
stronger the association between variable X and variable Y
When working with Pearson correlation coefficients (r) ranging from -1 to +1, the larger the absolute value of the measure (closer to +/- 1), the _____________________________________.
stronger the relationship between variables
According to Hill's criteria of causality, what are the contradictions to the Consistency criteria that it is an association that has been observed repeatedly.
studies of the same phenomenon can be expected to yield different results simply because they differ in their methods
What is a single-blind study?
subjects do not know what group they're in in order to prevent bias
The necessary cause does not always have to be _______________.
sufficient
Together the groups of component causes in the Sufficient Component Cause Model makes up a ____________________.
sufficient cause complex
Bias speaks to _______________ in solistiting, recording and interperating information
systematic bias
What are some frequent issues with numerators in incidence and prevalence measures?
the diagnosis of cases is not straightforward
The threshold within the dose-response curve refers to ____________________________________________.
the lowest dose at which a particular response occurs
What does the quality of epidemiological data affect?
the permissible applications of the data and types of statistical analyses that may be performed
What is a cohort design?
there is no intervention or randomization it is simply the measure of variables that might be relevant to the development of an outcome (morbidity, mortality) while observing who in the cohort develops (or developed) the disease
The _____________ is the squared deviation from the mean divided by the sample size that provides the average error between the mean and the observations from the sample.
variance (similar to mean deviation)
If scores are approximately normally distributed (have a bell shape), then: What mathematical facts are true?
•68% of the scores fall within +/- 1 sd of the mean *95% of the scores fall within between +/- 1.96 sd of the mean= Cuts off 5% of scores •*99% of scores are between +/- 2.58 sd= Cuts off 1% of scores •99.7% of the scores fall within +/- 3 sd of the mean •*99.9% of the scores fall within +/- 3.29 sd= Cuts off 0.1% of scores
T/F Quasi-experimental designs are cheep, easy and short.
False, Quasi-experimental designs are expensive, complex & time consuming
T/F The issue of causality in epidemiology is simple and involves the application of several causal criteria.
False, complex
T/F The lower the number of causal criteria that are satisfied by an observed association, the greater is the likelihood of a causal relationship.
False, greater
T/F Health policy is the same as law.
False, it's not the same as law but they are linked with the development of laws
T/F Estimates from samples are always the same as the population parameter because of sampling error.
False, never
T/F Epidemiology is a qualitative discipline.
False, quantitative
T/F The range is more accurate than the standard deviation because an outlier (extreme score) can greatly extend the range, making it a poor representation of the dispersion of scores
False, the standard deviation is more accurate than the range
______________ is the number of of live births reported in an area during a given time interval divided by number of women age 15-44 years in the area.
Fertility rate
_____________ is death of the fetus when it is in the uterus and before it has been delivered.
Fetal mortality
What is an example of neither necessary nor sufficient?
Most chronic diseases (e.g., CHD, cancer) that have multiple contributing causes, none of which causes the disease by itself
According to Hill's criteria of causality, what is the biological gradient association?
Most harmful exposures could be expected to increase the risk of disease in a gradient fashion e.g. if a little is bad, a lot should be worse
What is a web of causation?
a model used to depict a multivariate causality by using a spider-like web that portrays the disease and a complex of variables that play a causative role, but the web does not necessarily exhaust all possible risk factors
The ________________ is the number of deaths within a population due to a specific disease or cause divided by the total number of deaths from all causes in the population (and multiplied by 100).
Proportional mortality ratio PMR%
______________ - sample allocation is proportional to the strata population sizes
Proportional sampling
What does risk characterization inform policy makers?
Provides policy makers with a synopsis of all information that allows an informed decision about what to do and Yields a synthesis and summary of information about a hazard
________________ is the science and art of preventing disease, prolonging life, and promoting health through organized community effort.
Public Health
What is a sufficient cause?
a condition that guarantees the occurrence of a disorder- A cause (IV) that is sufficient by itself to produce the effect (DV)
What is necessary cause?
a condition that must exist for a disorder to occur- A factor (IV) whose presence is required for the occurrence of the effect (DV)
The Sufficient Component Cause Model is constituted from
a group of component causes, which can be diagrammed as a pie
_________________________ tested in analytic research is initiated with descriptive observations
Epidemiologic inference
What are the components of a randomized controlled trail?
1- for the study sample there is rigorous inclusion and exclusion criteria 2- random assignment to study conditions 3- blinding or masking to prevent bias in single-blind study or double-blind study 4- comparable measurements of outcomes (clinical endpoints) in treatment and control groups
What are the risk assessment steps?
1- hazard identification 2- dose-responce assessment 3- exposure assessment 4- risk characterization 5- risk management
The ____________________ is the number of deaths due to a disease that occurs among persons who are afflicted with that disease and provides a a measure of the lethality of a disease.
Case fatality rate CFR
___________________ of patients with particularly unusual presentations or combinations of symptoms often spur epidemiologic investigations.
Case reports
What are the types of descriptive epidemiological studies?
Case reports Case series Cross-sectional studies
How is data collected for a case-control study?
Case-control studies use a retrospective approach to collect exposure information Although data can be collected from other sources, (e.g., medical records) interviews are often used
What are examples of misclassifications?
Cases incorrectly classified as controls. Controls incorrectly classified as cases. Exposed incorrectly classified as non-exposed. Non-exposed incorrectly classified as exposed.
What is the recall bias?
Cases may remember an exposure more clearly than do controls
What is an ecologic study?
A study in which the units of analysis are populations or groups of people rather than individuals. Grouping (aggregate) measures represent characteristics of entire populations. Examples: nations, states, census tracts, counties
________________ is a philosophical concept merged with practical guidelines
Causation
What is an example of a Retrospective Cohort Study?
A study of mortality among an occupational cohort of shipyard workers employed at a specific naval yard during a defined time interval in the past.
Who is Alexander Fleming?
(1881-1955) discovered the antimicrobial properties of the mold Penicillium notatum in 1928 The antibiotic became available toward the end of World War II
What is the case fatality rate equation?
(Number of deaths due to disease "X"/ Number of cases of disease "X") *100
What is the Proportional mortality ratio PMR% equation?
(mortality due to specific cause during a time period/ mortality due to all causes during the same time period)*100
What are the advantages of a case-control study?
- Can be used to study low-prevalence conditions (rare diseases) in which Having a disease is a criterion for being selected as a case. - Relatively quick and easy to complete - usually inexpensive - Involve smaller number of subjects - Well suited to evaluation of diseases with long induction periods
What are the disadvantages of case-control studies?
- Measurement of exposure may be inaccurate - Representativeness of cases & controls may be unknown - Provide indirect estimates of risk - The temporal (time) relationship between exposure factor and outcome cannot always be ascertained - Prone to bias compared to other analytic designs, in particular, selection and recall bias
Pearson correlation coefficients (r) range from ________.
-1 to +1
What is a washout period?
-A period of time during which NO drug for the disease to be evaluated is given, in a crossover design study
What are some policy rules for epidemiologists?
1- Provide quantitative data regarding proposed health policies 2- Help to demonstrate the effectiveness of policies 3- Take an objective stance with respect to data collection 4- Conducting and disseminating their own research 5- Serving on expert groups that make policy recommendations 6- Serving as an expert witness in litigation 7- Testifying before a policy-making body (e.g., city council or state legislature) 8- Working as an advocate (e.g., within a health-related coalition) to achieve a specific policy objective"
When evaluating associations to declare with confidence that a "valid" statistical association exists what must be evaluated?
1- Chance must be considered to be an unlikely explanation for the findings 2- Sources of bias have been considered and ruled out (or taken into account) 3- Confounding has been evaluated and ruled out (or taken into account) 4- Misclassification has been checked
Epidemiologists ask whether a particular exposure is causally associated with a given outcome. BY following these steps:
1- First examine existing facts and hypotheses. 2- Then formulate a new or more specific hypothesis. 3- Obtain additional facts to test the acceptability of the new hypothesis.
What are the types of bias?
1- Hawthorne effect 2- Recall bias (including family recall bias) 3- Selection bias (including the healthy worker effect) 4- Information bias (interviewer or reporting bias) 5- Surveillance bias 6- Confounding 7- Misclassification
What are the causality criteria questions?
1- Is the association valid? 1a- Do the study findings reflect the true relationship between the exposure and disease? 2- Is the association causal? 2a- Is there sufficient evidence to infer a that a causal association exists between the exposure and the disease?
What is the criteria for a confounding factor?
1- Must be a risk factor (or protective factor) for the disease of interest. 2- Must be associated with the exposure of interest e.g. unevenly distributed between the exposure groups. 3- Must not be an intermediate step in the causal pathway between the exposure and outcome.
What are the types of associations?
1- No association (X is unrelated to Y) 2- Associated (X is related to Y) 3- Non-causal (X does not cause Y) 4- Causal (X causes 4a-Y) Directly X directly causes Y 4b-Indirectly X causes Z (intermediate step) that causes Y
What are the two major categories of cohort studies?
1- Population based- uses information from the total population or sample of a population 2- Exposure-based- compares cohorts with or without different exposures
What are the stages of the policy cycle?
1- Problem definition, formulation, and reformulation 2- Agenda setting 3- Policy establishment (i.e., adoption and legislation) 4- Policy implementation 5- Policy assessment
What are the types of cohort studies?
1- Prospective cohort study- Type of longitudinal design 2- Retrospective cohort study 3- Historical prospective cohort study
What are the seven factors that characterize study designs?
1- Who manipulates the exposure factor? 2- How many observations are made? 3- what is the directionality of exposure? 4- what are the methods of data collection? 5- what is the timing of data collection? 6- What is the unit of observation? 7- how available are the study subjects?
Of the ten essential public health services in the Core Public Health Functions Steering Committee developed a framework for essential services what can epidemiology aid with?
1- monitoring health status to identify and solve community health problems; 2- Diagnose and investigate health problems and health hazards in the community 9- Evaluate effectiveness, accessibility and quality of personal and population-based health services
How can epidemiologists contribute to public health policy?
1- performing research and sharing the results with others 2- joining policy-making bodies that have expertise in public health issues 3- contributing expertise to legal proceedings 4- offering expert testimony to the various policy-making arms of government from local to national 5- advocating on behalf of specific health policy initiatives
What are the two vital concerns of epidemiology?
1- quality of data available. 2- appropriate applications of the data.
What are the ethical guidelines of epidemiologists?
1-minimizing risks and protecting the welfare of research subjects 2- obtaining the informed consent of participants 3- submitting proposed studies for ethical review 4- maintain public trust 5- Meeting obligations to communities
What are Koch's postulates?
1. The same pathogen must be present in every case of the disease. 2. The pathogen must be isolated from the diseased host and grown in pure culture. 3. The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal. 4. The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.
1 standard deviations is equal to the ______________ percentile.
68.3% of data
3 standard deviations is equal to the ______________ percentile.
99.7% of data
What is the IV and DV of deterministic causality?
A cause (IV) is often an exposure An effect (DV) is often a health outcome
What is the public health policy Health in All Policies?
A collaborative approach to improving the health of all people by incorporating health considerations into decision making across sectors and policy areas
What is an example of necessary and sufficient cause?
A gene mutation associated with Tay-Sachs disease, a genetic disorder that results in the destruction of nerve cells in the brain and spinal cord
What is the goal of inference?
A goal of inference is to draw conclusions about a population from sample-based data
What is an interest group?
A group of persons working on behalf of, or strongly supporting, a particular cause, such as an item of legislation, an industry, or a special segment of society
According to Hill's criteria of causality, what is the plausibility association?
A known or postulated biologic mechanism by which the exposure might reasonably alter the risk of developing the disease is important
What is a case series?
A larger collection of cases of disease, often grouped consecutively and listing common features, i.e., characteristics of affected patients- a collection of individual case reports occurring within a fairly short period of time
What is a limiting factor of exposure assessment?
A limiting factor in risk assessment process especially when exposures occur at low levels
What is a policy?
A plan or course of action, as of a government, political party, or business, intended to influence and determine decisions, actions, and other matters
What is a health policy?
A policy that pertains to the health arena, for example, in provision of healthcare services, dentistry, medicine, or public health
What are the possible applications of clinical trials?
A prophylactic trial is designed to test preventive measures A therapeutic trial evaluates new treatment methods
What is a confounding variable?
A third variable that distorts the observed relationship between the exposure and outcome, and is associated with disease risk (exposure factor) that produces a different distribution of outcomes in the exposure group than in the comparison group
What is sampling error?
A type of error that arises when values (statistics) obtained for a sample differ from the values (parameters) of the parent population
__________________________ rates usually show greater variation than rates defined by almost any other personal attribute
Age-specific disease
____________________ is the number of cases per specific age group of population during a specified time period.
Age-specific rates
What does representativeness mean?
Also known as external validity and refers to the generalizability of the findings to the population from which the data have been taken
What is a disease?
An abnormal condition of an organism, especially as a consequence of infection, inherent weakness or environment stress, that impairs physiological or psychological functioning; broad array of health conditions that we seek to understand and ultimately modify, including physiologic states, mental health, and the entire spectrum of human diseases
What is an ecologic correlation?
An association between two variables (exposure and outcome) measured at the group level, Measure of interest is a correlation
According to Hill's criteria of causality, what is consistency?
An association that has been observed repeatedly
What is a pandemic?
An epidemic occurring worldwide, or over a very wide area, crossing international boundaries, and usually affecting a large number of people (Spanish Flu and Covid-19)
What is an example of statements of objectives?
An example of a statement of objectives can be found on the Healthy People website (healthypeople.gov)
What Hill criteria allow epidemiologists to hypothesis that associations that have already been demonstrated, also applies to similar evidence with a different drug or different viral disease in pregnancy.
Analogy
______________ studies are concerned with the etiology (causes) of disease and other health outcomes.
Analytic
___________ _________________ examines causal (etiologic) hypotheses regarding the association between exposures and health conditions.
Analytic epidemiology
________________________ examines associations among exposure variables and health outcome variables.
Analytic epidemiology
______________ in epidemiology, a specific exposure related to a disease.
Cause
____________________ are measures that refers to mortality (or frequency of a given disease) divided by the population size at the midpoint of a time period times a multiplier.
Cause-specific rate
According to Hill's criteria of causality, what is specificity?
Association is constrained to a particular disease-exposure relationship
______________ is a type of incidence rate used when the occurrence of disease among a population at risk increases greatly over a short period of time for example foodborne illness.
Attack rate
_____________ is used by the United States to monitor at the state level behavioral risk factors that are associated with chronic diseases.
Behavioral Risk Factor Surveillance System (BRFSS)
What are different types of information bias?
Bias in abstracting records Bias in interviewing Surveillance bias Reporting and recall bias
What are some examples of case reports in the textbook?
Bison encounters - Yellowstone National Park Adverse reactions due to cosmetic surgery in the US Imported rabid dog from Egypt
What is necessary and sufficient cause?
Both X and Y are always present together; nothing but X is need to cause Y- very uncommon in epidemiology
What are the strengths of a retrospective cohort study?
Can study the effects of exposures that no longer occur (e.g. discontinued medical treatments.) Quicker and less costly than prospective cohort studies. Particularly efficient for study of rare exposures and diseases with long latency periods Can examine multiple effects of single exposure Can yield information on multiple exposures May allow direct measurement of incidence of disease in exposed and non-exposed groups
How is the midrange calculated?
Calculate by adding together the smallest and greatest value and dividing by 2
What does Risk assessment calculated?
Calculates either qualitative or quantitative estimates of probability of undesirable outcomes, given exposure to a hazard
How is the mean deviation calculated?
Can calculate the mean deviances (differences) by subtracting the mean value from each of the observed values (Minus numbers represent the fact that the mean overestimates the data point Positive numbers indicate the mean underestimates the data point)
What are the strengths of prospective cohort studies?
Can elucidate temporal relationship between exposure & disease. Minimizes bias in the ascertainment of exposure (e.g. recall bias). Particularly efficient for study of rare exposures (not necessarily rare diseases). Can examine multiple effects of single exposure. Allows direct measurement of incidence of disease in exposed and non-exposed groups. Calculation of relative risk
What are case reports?
Careful and detailed report by one or more clinicians of a single occurrence of a noteworthy health-related incident or of a small collection of such events
What are national factors?
Climate Latitude Environmental pollution
__________________________ is assessed using effect size.
Clinically significant (relevance)
What are three examples of public health surveillance system?
Communicable and infectious diseases, Noninfectious diseases (asthma), Risk factors for chronic disease
________________________ is an individual cause of disease present within one or more sufficient causes.
Component cause
____________________ is a range of values that with a certain degree of probability contain the population parameter.
Confidence interval (CI) or estimate
What study designs are commonly utilized in epidemiologic research?
Cross-sectional Ecological Case-control Cohort
__________________ is the number of live births during a specified period (usually a year) per the resident population during the midpoint of the year.
Crude birth rate
__________ is a type of rate that has not been modified to take into account any of the factors, e.g., the demographic makeup of the population, that may affect the observed rate and the numerator consists of the frequency of a disease or death over a specified period of time while the denominator is a unit size of reference population.
Crude rates
What are the limitations to crude rates?
Crude rates reduce the standard of comparison to a common denominator- does not take into account the demographic makeup of a population
__________________ is a type of incidence rate when ALL individuals in the population are at risk throughout the time period during which they were observed.
Cumulative Incidence (CI)
___________________- are shorter-term changes in the frequency of a disease or other phenomenon over a period of several years or within a year.
Cyclic trends
___________________ _____________________ refers to epidemiologic studies concerned with characterizing the amount and distribution of health and disease within a population.
Descriptive epidemiology
What is the underlying premise of epidemiology?
Disease does not occur at random, but rather in patterns that reflect the operation of underlying factors
What is the Importance of analytic epidemiology to society?
Disease prevention Quantitative evaluations of interventions Safety and efficacy of drugs and medical procedures
According to Hill's criteria of causality, what is the consistency association?
Due to the inexact nature of epidemiologic investigations, evidence of causality is more persuasive when several studies conducted by different investigators at different times yield similar results
______________ ______________ describes a shift in the patterns of morbidity and mortality caused primarily to infectious & communicable disease to chronic, degenerative diseases.
Epidemiologic transition
_______________ - all strata contribute the same number to the sample
Equal (disproportion) sampling
What are the types of stratified random sampling?
Equal sampling, proportional sampling, optimum sampling
What is misclassification?
Erroneous classification of the exposure or disease status of an individual into a category to which it should not be assigned
What are the ecologic (ecological) fallacies?
Erroneous conclusions based on grouped data- Patterns observed on the aggregate level are not observed on the individual level
What is incidence useful for?
Estimates the risk (probability) of developing illness Measures the change from "healthy" status to illness. Useful to evaluate prevention programs Useful to forecast need for services & programs Useful for studying causal factors.
What is prevalence useful for?
Estimates the risk (probability) that an individual will be ill at a point in time Useful to plan for health-related services and programs
______________ is the action of using sample-based data to infer conclusions about the population.
Estimation
The seventh characteristics of study designs are to determine the availability of the study subjects. What does this mean when dealing with an observational study or an experimental study?
Ethical reasons may limit subject availability
____________ are the norms for conduct that distinguish between acceptable and unacceptable behavior.
Ethics
________ is the shared culture, such as language, ancestry practices and beliefs that is something one learns.
Ethnicity
What does a dose-responce assessment examine?
Examines the quantitative relations between the experimentally administered dose level of a toxicant and the incidence or severity of a response in test animals
What is an example of method of concomitant variation?
Example: Dose-response relationship between number of cigarettes smoked and mortality from lung cancer. The greater the number of cigarettes smoked, the higher the mortality levels from lung cancer. - dose response
What are an examples of ecological fallacies?
Example: Worldwide, richer cities (higher average income) have higher rates of CHD than poorer cities It would be incorrect to infer that richer individuals have higher rates of CHD than poorer individuals In fact, in industrialized cities poorer people have higher CHD rates than richer ones (Might be due to other factors, e.g., diet, access to health care, other factors, that confound the relationship on an individual level)
What is a direct causal association? Diabetes example?
Excessive sugar consumption is directly related to diabetes without the involvement of an intermediate step
What is the diabetes example for neither necessary nor sufficient model?
Excessive sugar consumption may or may not be present for individuals who develop Type II DM
What is an indirect causal association? Diabetes example?
Excessive sugar consumption might be related to obesity, which in turn is related to diabetes Obesity would be an intermediate step between sugar consumption and diabetes
___________________ indicates subsets of individuals who meet the eligibility criteria, but are likely to interfere with the quality of the data or interpretation of the findings.
Exclusion criteria
The fourth characteristics of study designs are to determine the methods of data collection. What does this mean when dealing with an observational study or an experimental study?
Existing, previously collected data Ecological studies Collection of new data - most other types
What are the disadvantages of cohort studies?
Expensive and time consuming Complicated and difficult to carry out Subjects may be lost to follow-up during the course of the study Exposures can be misclassified
______________ is the contact with factors (the IV) linked to adverse health outcomes (the DV), e.g., morbidity, mortality.
Exposure
The odds ratio is greater than 1 (>1). What does this mean?
Exposure is positively related to disease, and might be a causal factor. this statistic alone does not show a cause-effect relationship
What are the actions of risk management?
Exposure standards, pre-market testing requirements, recalls of toxic products, banning of hazardous materials
__________________ pertain either to contact with a disease-causing factor or to the amount of the factor that impacts a group or individuals
Exposures
Applying the conclusions of a study outside the context of that study is ______________________ or _____________________.
External Validity (Generalizability)
_________________ (generalizability) of sample - degree to which intended sample represents target & accessible (source) population.
External validity
What is an example of a population based cohort study?
Framingham, MA study of CHD
What is data mining?
Gathering and exploring large amounts of data in order to find formerly unrecognized patterns and associations in the data- Example: Political organizations contract for data mining to find out voters who favor a particular issue
Many differences in race/ethnicity are not due to race or ethnicity but instead may be due to:
Genetics Socioeconomic status Environmental exposures Access to health care Lifestyle factors How respondents self-classify
What is a Retrospective Cohort Study?
Go back in time to identify a cohort of individuals at a point before they developed the disease or outcome of interest
What is an example of cost-effectiveness (CE) ratio?
HIV prevention programs
What does epidemiology aids with?
Health promotion (both mental and physical health), Alleviation of adverse health outcomes, Prevention of disease
What are three examples of public health polices?
Healthy People, National Prevention Strategy, Health in All Policies
A ______________ is similar to a bar chart but used for shows the frequency of cases for categories of continuous variables.
Histogram
Today universities and many health-related facilities maintain _____________________________________________ to ensure all research proposals that involve humans or animals meet requirements for informed consent and other ethical standards.
Human Subjects Review Boards/IRBs
_______________ ______________ refer to those that become more lethal due to things like antibiotic resistance and mutations (in part due to man-made issues)
Hybristic infections
A _______________ is any conjecture cast in a form that will allow it to be tested and supported or refuted.
Hypothesis
What is an example of an association study?
Hypothetical Example: Sugar and Non-Insulin-Dependent Diabetes- Sugar consumption (exposure variable) and type 2 diabetes (health outcome) Possible associations between exposure and outcome: No association (statistically independent) between dietary sugar consumption and occurrence of diabetes Positive association between dietary sugar and diabetes Negative association between dietary sugar consumption and diabetes
What is the quote from Medewar?
I cannot give any scientist of any age better advice than this: The intensity of the conviction that a hypothesis is true has no bearing on whether or not it is true (Medewar, 1979)
What is probabilistic causality?
If X, then likely Y. The reason why X may not lead to Y is due to random chance- stochastic causes
What is surveillance bias?
If a population is monitored over a period of time, finding out about an outcome may be better in the monitored population than in the general population- May lead to biased estimate of exposure/disease relationship
How do you interpret odds ratio?
If the OR = 1, the odds of exposure are the same for cases and controls,Indicates no association between exposure and outcome If the OR is >1, there is increased frequency of exposure among cases Exposure is positively related to disease, and might be a causal factor. An OR of 2.1 (about 2) suggests that the odds of disease are about two times higher among the exposed than among the non-exposed. If the OR is <1, exposure is negatively related to disease The exposure might be a protective factor.
Why where the worldwide smoke-free bar laws implemented?
Implemented due to information about the health hazards that secondhand cigarette exposure presented in the work setting
What is an example of international variation?
In 2020, the wild (endemic) poliovirus remained in Afghanistan & Pakistan Health authorities from the African Regional Certification Commission for Polio Eradication declared Africa free of the wild poliovirus, though cases of vaccine-derived polio are still sparking outbreaks in more than a dozen countries Possible that scattered cases of the wild poliovirus still remain undetected due to patchy surveillance across the African continent
What is attributable risk?
In a cohort study, refers to the difference between the incidence rate (IR) of a disease in the exposed group and the incidence rate in the non-exposed group An alternative to relative risk
What is an example of operationalization?
In a study of the association between tobacco use and lung disease, the variables might be the number of cigarettes smoked (or the duration of smoking) and the occurrence of asthma. Variables are often operationalized by questionnaires and review of medical records
What are experimental studies?
In epidemiology, experimental studies are implemented as intervention studies. Experimental research is able to examine whether a cause-and-effect relationship exists between two variables
What are some examples of secular trends?
In the U.S., mortality from heart disease has been gradually declining, whereas cancer mortality has been gradually increasing Yearly suicide rates (See slide 68) Higher among males than females U.S. females—suicides by suffocation increased Age-adjusted prevalence of hypertension (See slide 69) No secular trend shown for hypertension, but a upward trend in high blood pressure control
What is an example of observed association may simply be a coincidence?
In the last 10 years incidence rates for prostate cancer have increased, as have sales of SUVs and plasma TV screens. - positive association is not always causal
_________________ refers to the occurrence of NEW cases of a disease or mortality within a defined period of observation (e.g., a week, month, year, or another time period) in a specified population that was previously disease-free or condition-free (at risk) and it qualifies the development of disease frequency.
Incidence
____________________ is Formed by dividing the number of new cases that occur during a time period by the total person-time of observation and is a measure of time of observation, not people aka force of morbidity
Incidence density
___________ is the rate at which new events occur in a population calculated by dividing the number of new cases that occur during a time period (numerator) by the number of individuals in the population at risk during the time period (denominator).
Incidence rate
What does birth statistics include?
Include live births and fetal deaths Presumed to be nearly complete Used to calculate birth rates Helpful in understanding birth defects, length of gestation, birth weight, and demographic background of the mother
______________ also called eligibility criteria, defines main characteristics of target & source (accessible) populations that will provide a basis for generalizing conclusions.
Inclusion criteria
What measures are composited to determine socioeconomic status (SES)?
Income level Education level Type of occupation Area of residence Lifestyle
What are factors that cause prevalence to increase?
Increase in incidence Longer duration of the case In-migration of cases Prolongation of life of patients without a cure
What is increased risk?
Increased risk is calculated as (Relative Risk - 1) × 100.; Increased risk: Men with diabetes increase their risk of coronary heart disease by 200% compared to men without diabetes
In a case-control study what does the investigator investigate?
Investigator queries both groups about previous exposures that may have led to the outcome under study -Determines and compares the proportion of cases who have experienced the exposure of interest with the proportion of controls who experienced the exposure
What population is used in a prospective cohort study?
Investigator starts with disease free subjects who have been exposed to a factor of interest Subjects are observed over time for development of new cases (incidence) of a disease or other health event
What is decision analysis?
Involves developing a set of possible choices and stating the likely outcomes linked with those choices- Each of the possible choices may have associated risks and benefits
What are Computes cost-effectiveness (CE) ratios?
Involves dividing the costs of an intervention by its outcomes expressed as units (often deaths averted)
What is an odds ratio?
It is an indirect measure of risk because incidence rates have not been used
The _____________________________ is associated with specific environmental conditions that may exist in a particular geographic area.
Localized patterns of disease
What are some examples of racial/ethnic differences in health characteristics.
Lower frequency of asthma reported among Asians and Hispanics compared to other groups (See next slide) Hispanics more frequently report that they have no usual source of medical care compared to Non-Hispanic whites and non-Hispanic blacks (See slide 46) Difficulties in physical functioning are highest among adults classified as Native Hawaiians and Pacific Islanders (See slide 47) Incidence of gonorrhea is higher among non-Hispanic blacks than other groups (See slide 48)
When ranking epidemiologic studies what types of studies are ranked lowest to highest?
Lower rankings for case studies, case reports, cross-sectional studies, ecologic studies Higher rankings for analytic studies including case-control studies and cohort studies Highest rankings for intervention studies, especially clinical trials
What is an example of localized patterns of disease?
Lung cancer and radon gas An issue in Pennsylvania among other places Naturally occurring arsenic in water supply Presence of disease vectors (intermediates, e.g., insects or animals, involved in the transmission of disease agents) Dengue fever along the Texas-Mexico border A viral disease transmitted by mosquitos
What are two examples of relative risk caulations?
MI (heart attacks) in those who smoke cigarettes compared with those who do not, negative exposure Covid-19 incidence in those who got vaccinated vs those who did not, positive exposure
According to the sufficient component cause model more than ______________________________.
More than one sufficient cause complex can be implicated in the etiology of a disease However, the necessary cause must be present in every causal complex
What are the advantages of ecologic studies?
May provide information about the context of health. Can be performed when individual-level measurements are not available. Cheap, quick, and simple (generally make use of secondary data). Can be conducted rapidly and with minimal resources.
What are place variables?
Morbidity and mortality vary greatly with respect to place (geographic regions) International National (within-country) Urban-rural differences Localized patterns of disease
Analytic studies explore associations between exposures and outcomes: What are the two categories of analytic studies?
Observational design, investigator: Does not have control over the exposure factor Usually is unable to assign subjects randomly to study conditions Experimental design, investigator: Controls who is exposed to a factor of interest Assigns subjects randomly to study groups Helps prevent confounding and other issues
What are two examples of cohort effects?
Occupational exposures during a specific time period Coal mine workers that developed black lung disease from coal dust exposure in NEPA and West Virginia among other places Birth year or other commonality WWII vets who were given free cigarettes during the war and eventually developed lung cancer Vietnam vets who were exposed to agent orange and developed a number of neurological diseases
What happens when there is selection bias?
Occurs when selection of study subjects (whether selection by exposure or disease status) is based on different criteria Results in the study groups being non-comparable, unless some type of statistical adjustment can be made
The ____________is a measure of the association between the frequency of exposure & outcome used in case-control studies.
Odds Ratio (OR)
The second characteristics of study designs are to determine how many observations are made. What does this mean when dealing with an observational study or an experimental study?
One Cross-sectional study, many ecologic studies, most case-control studies Multiple times- Cohort and experimental studies
________________ - sample allocation is proportional to both the strata population size and variability
Optimum sampling
________________ is a measurable attribute (characteristic) of a population.
Parameter
How are cohort studies observed?
Participants are observed over time (going forward or backward) to gather information about exposures such as Dietary habits, BMI, exercise status, vaccine
_____________ refers to late fetal deaths and deaths among newborns defined as the number of late fetal deaths after 28 weeks or more gestation plus infant deaths within 7 days of birth divided by the number of live births plus the number of late fetal deaths during a year
Perinatal mortality
___________________ is all cases of a disease within a period of time which could be a week, month, year, or any other interval
Period prevalence
What are the advantages of cohort studies?
Permit direct observation of risk Exposure factor is well defined Can study exposures that are uncommon in the population The temporal relationship between factor and outcome is known
What are the aims of descriptive epidemiology?
Permit evaluation of trends in health and disease Provide a basis for planning, provision, and evaluation of health services Identify problems to be studied by analytic methods and suggest areas that may be fruitful for investigation
What is the poverty guideline for 48 contiguous states and DC? 2021
Persons in family/household Poverty Guideline 1 $12.880 2 $17,420 3 $21,960 4 $26,500 5 $31,040 6 $35.580 7 $40,120 8 $44,660
What are the stages/phases of clinical trials?
Phase I: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects Phase II: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety Phase III: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow it to be used safely (Covid-19 trials) Phase IV: Studies are done after the drug or treatment has been approved and marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
___________________ is a single value chosen to represent the parameter.
Point estimate
________________ is all cases of a disease, health condition, or deaths that exist at a specific point in time relative to a specific population (group) from which the cases are derived.
Point prevalence
What is an example of spurious association that was found to be noncausal?
Polio and spongy tar- kids playing on hot cement= polio? but no
A collection of people who share common observable characteristics is a _______________.
Population
________________ is all the inhabitants of a given country or area considered together.
Population
________________ refers to all inhabitants of a given area considered together.
Population
What are the six key characteristics of epidemiology?
Population focus Distribution Determinants Outcomes Quantification Control of health problems
What is a positive correlation?
Positive (+) values: as the values of one variable increase, the values of the other variable also increase
Variables that are associated with one another can be positively or negatively related, explain positive associations and negative associations?
Positive association means that as the value of one variable increases, the value of the other variable increases Negative (inverse) association means that as the value of one variable increases, the value of the other variable decreases (Tested with Stats correlation tequniques)
________ is the ability of a study to find an association if one exists.
Power, set to 0.80 or 80%
_______________ is the number of of existing cases (presence) of a disease, health condition, or deaths in a population at some designated time and is expressed as a proportion.
Prevalence
What are the limitations of cross-sectional studies of the health status of a study group (hopefully a randomly selected from the population) at a certain point in time studies?
Prevalent (existing) rather than incident (new) cases are used The exposure ("snap-shot" info) could be associated with survival after disease occurrence, rather than development of the disease They are just a "snap-shot" so temporal (time) sequence between exposure and disease cannot be established
Descriptive epidemiological studies provide valuable information for?
Prevention of disease Design of interventions Conduct of additional research
______________________ is the systematic and and continuous gathering of information about the occurrence of diseases and other health phenomena using syndromic surveillance.
Public health surveillance
_______________ is word data that can be given numerical value.
Qualitative data
_______________ refers to counting cases of illness or other health outcomes.
Quantification
__________________ is data reported as a numerical quantity.
Quantitative data
How do you intemperate relative risk?
RR of 1.0 means there is no difference in risk between the groups. greater than > 1 suggests an increased risk of that outcome (such as developing hypertension) in the exposed group less than <1 suggests the exposure protects participants from the outcome
________ is the physical differences that groups and cultures consider socially significant.
Race
What is a noncausal positive association? Diabetes example?
Random event - If there is a positive association is observed it could be due to chance This is tested statistically to rule out chance. Ex. A third factor (genetic predisposition) may be related to both preference for dietary sugar and occurrence of diabetes.
___________________ is a selecting sampling method in which all individuals in the accessible population have an equal chance of being selected.
Random probability sampling
How are epidemiologic studies ranked?
Ranked for validity of etiologic inference
What does availability of the data mean?
Refers to the investigator's access to data- Use of patient records and databases in which personally identifying information have been removed may be permitted to a researcher
According to Hill's criteria of causality, what is an analogy? example?
Relates to the similarity between known associations and one that is being evaluated for causality; ex. thalidomide given to mothers to prevent nausea and birth defects; contracting rubella (German measles) during pregnancy and birth defects, still births, and miscarriages
What is an example of case series?
Reported cases of primary meningoencephalitis, a highly fatal disease 121 cases reported between 1937 and 2007 Most cases were male, median age = 12 years Primary exposure source: fresh water in lakes and rivers
The third characteristics of study designs are to determine the directionality of exposure. What does this mean when dealing with an observational study or an experimental study?
Retrospective approach - information about exposures that occurred in the past Case-control study, retrospective cohort study Single point in time - taking a snap-shot Cross-sectional study Prospective approach - information about outcomes is collected in the future Experimental and prospective cohort studies
What German physician created the postulates that demonstrated the association between a microorganism and disease?
Robert Koch
A _____________ is a subgroup that has been selected, by using one of several methods, from the population.
Sample
______________ refers to a subset of the population.
Sample
______________ and _____________ both impact on power.
Sample size, effect size
What are some examples of Cyclic trends?
Severe weather events in the Atlantic basin (See slide 71) Increase in the number and severity of hurricanes Mortality from pneumonia and influenza (flu) Peaks during February Occurrence of enteroviruses (See slide 72) Example - "stomach or intestinal" virus Seasonal variation of infections including Covid-19
In case-control studies, the control does not have the disease state. How do you find the control group?
Similar to sources for cases (not registries) but individuals with different health problems, friends/ relatives of cases, or people in the community
What is the method of difference similar to?
Similar to the random clinical trials (RCTs) used to evaluate new medications/clinical procedures
What do small and large standard deviation scores mean?
Small sd (relative to the mean) indicate that data points are close to the mean Large sd (relative to the mean), indicates the data points are distant from the mean
What is an example of the causality criteria?
Smoking and Health, 1964 Surgeon General's report Explored the relationship between smoking tobacco and lung cancer Presented several criteria for evaluation of a causal association Concluded there was a positive causal relationship between the exposure and outcome
____________________ is defined as a descriptive term for a person's position in society and it summarizes the variable that is an unreliable measure.
Socioeconomic status (SES)
_____________ are the numbers that describe a sample.
Statistics
___________ selects participants through randomly selecting samples from each of several strata (subgroups).
Stratified Sampling
What are the strengths of cross-sectional studies of the health status of a study group (hopefully a randomly selected from the population) at a certain point in time studies?
Strengths Provide prevalence estimates of exposure and disease for a well-defined population Easier to perform than studies that require follow-up (hence relatively inexpensive) Can evaluate multiple risk (and protective) factors and health outcomes at the same point in time May identify groups of persons at high or low risk of disease Can be used to generate hypotheses about associations between predictive factors and disease outcomes
What are the strengths and weaknesses of case reports?
Strengths- Provide very early warning of a possible problem; Limitations - No appropriate comparison group Cannot be used to test for presence of a valid statistical association Since they are based on the experience of one person Presence of any risk factor maybe purely coincidental
What are the strengths and weaknesses of case series?
Strengths- Used as an early means to identify the beginning or presence of an epidemic Can suggest the emergence of a new disease, e.g., AIDS; Limitations- Lack of an appropriate comparison group Cannot be used to test for presence of a valid statistical association
_________________ is a procedure to identify illness clusters early, before diagnoses are confirmed and reported to public health agencies.
Syndromic Surveillance
What is interviewer bias?
Systematic difference in the soliciting, recording, or interpretation of information from study participants Can affect every type of epidemiologic study May occur when interviewers are not "blinded" to exposure or outcome status of participants Interviewer's knowledge of subjects' disease status may result in differential probing of exposure history and/or recording of the outcome under examination
What is information bias?
Systematic differences in the way in which data on exposure and outcome are obtained from the various study groups.
_______________ selects participants through randomly choosing every n^th person after a random start.
Systematic sampling
What are two examples of registers?
The National Program of Cancer Registries (NPCR), The Surveillance, Epidemiology, and End Results (SEER) Program, National Health Interview Survey (NHIS)
What is an example of necessary but not sufficient?
The SARS-CoV-2 virus is a necessary requirement for the Covid infection, but not everyone who is exposed to the virus will develop the disease- The development of the disease is influenced by other factors that affect immunity.
What is confounding?
The distortion of a measure of the effect of an exposure on an outcome due to the association of the exposure with an extraneous factor that influences the outcome
What example was used to represent the web of causation?
The etiology of CHD involves a complex interplay of exposures and risk factors
What is the goal of cohort studies?
The goal of cohort studies is to compare the incidence of disease among the exposed to the incidence in the unexposed Expressed as a relative risk (RR)
What is the goal of the National Health Interview Survey (NHIS)?
The goal of the survey is to collect data about people's health status and access to health care from a representative sample of the U.S. population
What are different kinds of data?
The kind of data including the source and content- Vital statistics, surveillance data, disease statistics, data from case registries, records from health care and insurance programs
How does a study pass Hills nine criteria?
The more criteria that are satisfied, the more convincing is evidence in support of a causal association
In a case-control study, For each control group, how many controls per case?
The optimal case-control ratio is 1:1 When the number of cases is small, the sample size for the study can be increased by using more than one control (e.g., 1:2, 1:3, 1:4) The benefit of increased sample size (e.g., increase in statistical power) is not as relevant past the 1:4 ratio
What is exposure assessment?
The procedure that identifies populations exposed to the toxicant, describes their composition and size, and examines the roots, magnitudes, frequencies, and durations of such exposures
What are epidemiological inferences from descriptive data?
The process of inference refers to drawing conclusions about the nature of exposure and health outcomes; Allows for the generation of hypotheses
What is legitimization?
The process of making policies fair, to be acceptable to the norms of society
T/F A sampling frame is often much larger than the sample size required for a study.
True
What is relative risk?
The ratio of the incidence rate of a disease or health outcome in an exposed group to the incidence rate of the disease or condition in a non-exposed group
One of the component causes in the model is a necessary cause.
The remaining component causes are not necessary causes
According to Hill's criteria of causality, what is the strength association?
The stronger the association, the less likely the relationship is due merely to some unsuspected or uncontrolled confounding variable
____________ are general accounts of causal relationships between exposures and outcomes.
Theories
Should there be two-way arrows between hypothesis and theory and between hypothesis and explanatory model?
Theories guide hypotheses but after they are tested and accepted or rejected they may guide theory and explanatory models. The hypothesis also guides theory and explanatory models.
What is the risk assessment use of epidemiology?
To estimate from the group experience what are the individual risks on average of disease, accident and defect, and the chances of avoiding them
What is the disease causality use of epidemiology?
To search for causes of health and disease by examining the experience of groups defined by their composition, experience, behavior and environments
T/F According to method of difference, frequency of a disease that varies across two settings (or two situations) that is hypothesized to result from variation in a single causative factor (the "cause" of the disease).
True
T/F Any one of the Hill Criteria taken alone is not sufficient to demonstrate a causal relationship.
True
T/F Case reports are a very basic type of descriptive study.
True
T/F Census 2000 was the first to allow respondents to check a multiracial category.
True
T/F Correlation does not equal causation.
True
T/F Correlations do not describe or even imply causation.
True
T/F Descriptive studies often help to generate research hypotheses.
True
T/F Ecologic studies (studies that that represent characteristics of a group, i.e., the entire population not an individual) is a type of descriptive study.
True
T/F Generally there has been a decline in infectious disease mortality over time.
True
T/F Health effects range from reductions in lower level conditions (immune status) to catastrophic (mortality).
True
T/F Incidence is the number of new cases of disease in a population during a specific period of time per unit of population.
True
T/F Infectious and chronic diseases also show considerable variation in incidence and prevalence within a country.
True
T/F Involvement of epidemiologists in the policy arena is growing.
True
T/F Most epidmeiological studies do not use random samples.
True
T/F Outcomes don't always have to be cast in negativity.
True
T/F Race & ethnicity are somewhat ambiguous characteristics that overlap with nativity and religion.
True
T/F Risk characterization integrates hazard identification, dose-response assessment, and exposure assessment.
True
T/F Some consider clustering the same as cohort effects.
True
T/F Some scientists have proposed that race is a social and cultural construct, not a biological construct.
True
T/F Strong, inverse association of SES with levels of morbidity and mortality. Those in the lowest SES positions are confronted with excesses of morbidity and mortality from numerous causes, including lack of access to health care
True
T/F The confidence intervals are the plausible range of values around a sample mean for generalizing back to the population.
True
T/F The epidemiologist must rule out chance, which may account for observed associations.
True
T/F The period prevalence is always greater than the point prevalence.
True
T/F The set of causal criteria offered by Hill are useful but are also saddled with reservations and exceptions.
True
T/F The stochastic process incorporates an element of randomness.
True
T/F This is the reason why CI are used to give an approximate range for where the population parameter is likely to be found.
True
How is TB an example of the sufficient component cause model?
Tubercle bacillus is the necessary cause in complex I and II - to develop tuberculosis (TB) one must be infected with the bacterium However exposure to the bacterium is not sufficient cause for contracting TB A number of component causes (personal & environmental factors) operate in addition to exposure to the bacillus to cause TB The additional component causes are not necessary causes
What is an example of a US ethical research violation?
U.S. Public Health Service Syphilis Study at Tuskegee Syphilis investigation from 1932 to 1972 Purpose was to "record the natural history of syphilis in hopes of justifying treatment programs for blacks" A total of 600 African American men participated 399 syphilis cases and 201 syphilis-free controls. Never gave informed consent. Despite discovery of penicillin, men were never offered treatment. Class-action suit filed in 1973 resulted in a $10 million settlement plus medical and health benefits
The _____________________________________ provides data that can be used to define the denominator in rates. SUch as official esitmates of total population size and subdividions of the population by geographic area.
US Bureau of the Census
What government agency is responsible to ban the use of BPA in plastics but has not done it yet because "human data is not conclusive"?
USDA
___________ is the total set of elements from which a sample is selected.
Universe
Proved an example of the differences between urban and rural living.
Urban example: Elevated occurrence of lead poisoning among children who live in older buildings (many cities) or among those living in a city with contaminated water (Flint, MI); Rural example: Pesticide exposure and farming injuries among agricultural workers Migrant workers are especially at risk
______________ is any quantity that can have different values across individuals or study units and the opposite of a constant.
Variable
What is an example of sufficient but not necessary cause?
Vietnam vets exposed to a Agent Orange (herbicide and defoliant chemical) had children with an increased rate of birth defects- However, exposure to a number of drugs also causes an increased rate of birth defects
_______________ include include deaths, births, marriages, divorces, and fetal deaths.
Vital events
What are the three defining features that characterize big data? (three Vs)
Volume, Variety, Velocity
How do you determine internal validity in an experimental design?
Were subjects randomly assigned? Were appropriate and reliable measures taken? Were the measures valid? Was the analysis correct?
What is an example of confounding?
What factor might confound the association between birth order and Down's syndrome?- is the Mean Age of Mothers
What questions should always be considered when using big data or any data?
What is the nature of the data, including sources and content? How available are the data to the investigator? How complete is the population coverage? What are the appropriate & inappropriate uses of the data?
Since disease not does occur at random, epidemiologists are concerned with: what about people?
What kinds of people tend to develop a particular disease Who tends to be spared? What's unusual about both groups of those people?
What are the 6 major race/ethnicity categories?
White Black or African American American Indian and Alaska Native Asian Multiple subcategories Native Hawaiian and other Pacific Islander Multiple subcategories Some Other Race (fill-in)
History of causality of disease moved through the following:
Witchcraft, demons, gods - wrath of gods or demons Environmental influences - climate, geographic location, water quality (Hippocrates) Theory of contagion - infections are caused by transferable seed-like beings or germs (Fracastoro) Miasmas - airborne toxic vapor composed of malodorous particles from decomposing fetid materials or water-borne organisms (the latter from Snow) Spontaneous generation - microorganisms, insects could arise spontaneously from nonliving material Germ theory - linked microorganisms to disease (Koch, Pasteur)
What is a source of international epidemologic data?
World Health Organization (WHO) studies: Both infectious and chronic diseases show great variation from one country to another. Climate, cultural factors, national dietary habits, and access to health care affect disease occurrence
What is sufficient but not necessary cause?
X may or may not be present when Y is present, because Y has other causes, and can occur without X- X is one one the causes of the disease, but there are others
What is neither necessary nor sufficient?
X may or may not be present when Y is present- If X is present with Y, some additional factor must also be present, X is a contributory cause of Y
What is necessary but not sufficient?
X must be present when Y is present, but Y is not always present when X is- X is necessary for causation of Y, but X by itself does not cause Y
Cause is ____ and Effect is ____.
X, Y
What is risk ratio or risk rate in a Retrospective Cohort Study?
a comparison between exposed and non-exposed
What is an epidemiological triangle?
a model used to depict a multivariate causality in which there are three major factors: Agent (mosquitoes,giardia, bacteria, viruses) , Host (age, immunity, personal hygiene), Environment (general sanitation, climate, presence of reservoirs of disease agents); and they operate jointly in the causation of infectious disease
Prevalence shows and measures _________________________.
a snapshot of disease or health event
What is an illness?
a subjective state of the person who feels aware of not being well
What is the Hawthorne effect?
a type of bias in which Participants' behavior changes as a result of their knowledge of being in a study; causing the avis effect- when the control group knows they are in the control group and try harder to beat the other group
What is the healthy worker effect?
a type of selection bias that shows employed populations tend to have a lower mortality experience than the general population
Why were laws implemented against the use of Bisphenol A (BPA) as an ingredient used in the manufacture of plastics.
because more than 90% of US populations have detectable levels in their urine and there is cause for concern that BPA exposures in fetuses, infant and children causes developmental changes
The scope or amount of disease is called the ___________________ in the population.
burden of disease
Descriptive studies include _____________________________________.
case reports, case studies, and cross-sectional studies.
What is exposure?
catch-all term for agents, interventions, conditions, policies, and anything that might affect health
The determination of ________________________ between exposure and outcome is a difficult issue for epidemiology as it relies primarily on observational studies, not RCTs
causal relationships
The odds ratio statistic alone does not show a ___________ relationship.
cause-effect
What is the Avis effect?
caused by the Hawthorne effect, it is when the control group knows they are in the control group and try harder to beat the other group
The field of inferential statistics explores the degree to which ___________________________________________________________.
chance affects the conclusion that can be inferred from data
What information does case series provide?
clues for the identification of a new disease or adverse effects of exposures
What is an excellent website for trusted information about many health issues?
cochrane.org named after Archie Cochrane, a physician, Browse the Cochrane library
A_________ is defined as a population group, or subset, distinguished by a common characteristic, that is followed over a period of time.
cohort
What is the method of difference?
compares and contrasts cases with the same attributes but different outcomes, and determines causality by finding an attribute that is present when an outcome occurs but that is absent in similar cases when the outcome does not occur; All of the factors in two or more settings are the same except for a single factor
The smaller the standard error and ____________ the more confidence inferences can be drawn about the population based on sample data.
confidence interval
Due to the random sampling error __________________ are used to estimate the population parameter from the specific sample.
confidence intervals
Why were the trans-fats laws implemented?
consumption of manufactured hydrogenated vegetable oils is associated with adverse cardiovascular effects
What does epidemiologic reasearch address?
contemporary health-related problems such as Risks associated with smoking, obesity, cancer, and heart disease, Prevention of youth violence, Factors associated with substance abuse, Spread and risks of Covid-19
A _____________ is a type of table that tabulates data according to two dimensions through columns and rows known as marginal totals. Example: " A = exposure is present and disease is present. B = exposure is present and disease is absent. C = exposure is absent and disease is present. D = exposure is absent and disease is absent."
contingency table
How do you work with confounding variables?
control confounders by Using study groups that are similar with respect to confounders and Use random assignment, match subjects, use statistical procedures (multivariate analysis) or hold those variables constant
What is an adjusted odds ratio?
controls for confounding variables
______________ studies classify a disease or other health outcome according to person, place, & time.
descriptive
The field of ________________ classifies the occurrence of disease according to the following variables: Person - who is affected Place - where the condition occurs Time - when and over what time period the condition has occurred
descriptive epidemiology
A __________________ is a collective or individual risk factor (or set of factors) that is causally related to a health condition, outcome, or other defined characteristic.
determinant
Descriptive studies generally precede analytic studies that are designed to investigate _______________ of disease
determinants
The Sufficient Component Cause Model is a type of ______________________ also known as the causal pie model (Rothman).
deterministic model
What is the outcome variable in epidemiologic research?
disease
What is the most important use of epidemiology?
disease causality use
What is the historical use of epidemiology?
documents the patterns, types, and causes of morbidity and mortality over time
A _______________________ is a type of chart that looks at the correlative association between exposure and effect.
dose- response curve
What are examples of observational analytic studies?
ecologic, case-control, cohort
Stronger the association, larger the ______________, and the easier it is to have a significant finding.
effect size
When using Hills nine criteria of causal association the ________ criteria is evaluated.
entire
Environmental policies may incorporate ____________________.
environmental objectives
The participants of a Retrospective Cohort Study are separated into what two groups?
exposed and not exposed
What is the explanatory variable in epidmiologic research?
exposure
Deterministic causality has _____________ and ________________ causes.
necessary and sufficient
A major concern of epidemiology is to assert that a causal association exists between an ________________________________________
exposure factor and a disease or other adverse health outcome.
One of the central concerns of epidemiology is to be able to assert that a causal association exists between an ____________________________________.
exposure factor and disease in the host.
What are the challenges to the validity of study designs?
external validity, sampling error, internal validity, bias
What are the two fetal mortality measures?
fetal death rate and late fetal death rate
What is an example of a Quasi-experimental design?
fluoridation in 2 cities in NYS
What is an example of a prospective cohort study?
following people who smoke cigarets to see if they develop a disease
A prospective cohort study is also called a longitudinal or follow-up study and it goes _____________ in time.
forward
A ____________________ table is used to tabulate cases and clean data so that the data is ready for coding and analysis.
frequency distribution table
Descriptive epidemiology and descriptive studies provide a basis for _________________________.
generating hypotheses
The researchers in a Retrospective Cohort Study identify and enroll participants after the outcomes have occurred and then ___________________ to check on exposure status.
go back in time
What does relative risk express?
how much more (or less) likely it is for the exposed person/group to develop an outcome compared to an unexposed person/group; more- RR greater than 1, less- RR is less than 1
How are quasi-experimental study different from a randomized control trail?
in a quasi-experimental study it does not assign individual subjects randomly to the exposed and non-exposed groups
What is the major deficiency of reportable and notifiable disease statistics?
incomplete population coverage due to limited information about persons who develop a disease and do not seek medical attention, asymptomatic individuals, physicians failure to fill out proper forms
What are ethics in research?
informed consent, freedom from coercion, protection from harm, risk-benefit analysis, deception, debriefing, confidentiality
A variable measured on an ____________ consists of items in mutually exclusive categories with equal distances between values, but the zero point is arbitrary (no absolute zero)
interval scale
An ________________ is an investigation involving intentional change in some aspect of the status of the subjects
intervention study
Experimental design is an analytic study. How does it work?
investigator: Controls who is exposed to a factor of interest Assigns subjects randomly to study groups Helps prevent confounding and other issues
Observational design is an analytic study. How does it work?
investigator: Does not have control over the exposure factor Usually is unable to assign subjects randomly to study conditions
Even if the chance, bias, and confounding have been sufficiently ruled out (or taken into account)___________________________________________________________________.
it does not necessarily mean that the valid association observed is causal.
The 99% CI is ________ than the 95% CI because it is larger range of the population mean.
less useful
What are the limitations of randomized control trails?
limited to a narrow range of applications because it is not useful for studying the etiology of disease and by ethical issues in participant assignment.
How is the count measurement lacking?
limited usefulness for epidemiologic purposes without knowing size of the source population
At what levels does public health surveillance operate?
local, national, & international levels
A _________________ is one in which the cases and controls have been matched according to one or more criteria such as sex, age, race, or other variables.
matched case-control study
The ___________ is the number that is midway between the smallest and greatest values of the data set.
midrange
A _______ is the category in a frequency distribution that has the highest frequency of cases.
mode
A _________________ is one that has several peaks in the frequency of a condition.
multimodal curve
Internal validity _______ always be the primary objective since an invalid result __________ be generalized.
must, cannot
The Sufficient Component Cause Model is similar to the ______________________________________.
necessary but not sufficient cause model, but, the necessary cause in conjunction with the component causes forms a sufficient cause complex
_________________ is the number of number of infant deaths under 28 days of age divided by number of live births during a year.
neonatal mortality rate
Does a convenience sample (grab bag sample) demonstrate external validity?
no, Random samples are more likely to demonstrate external validity than are convenience samples
Local and state health departments report ___________________________________to CDC and WHO.
notifiable and reportable diseases
Incidence shows and measures ________________________.
number of new cases of a disease
What is the numerator and denominator of relative risk (RR)?
numberator= Incidence rate in the exposed denominator= Incidence rate in the non-exposed
Epidemiologic inference is initiated with ________________.
observations
What is an epidemic?
occurrence in a community or region of cases of an illness, specific health-related behavior, or other health-related events clearly in excess of normal expectancy (Covid-19)
What is family recall bias?
occurs when cases are more likely to remember the details of their family history than are controls. Can lead to an overestimation of an association between an exposure and a health outcome. (cleft pallet kids and illness during pregnancy)
What is the odds ratio equation?
odds of having the exposure among those with the disease (cases)/(divided by) odds of having the exposure among those without disease (controls)
The odds of having the exposure among those with the disease (case) compared to the odds of having the exposure among those without the disease (controls). Is the _____________.
odds ratio
What is the crude death rate used to project?
population changes
Epidemiology is sometimes called ___________________ because it does not focus on the individual like clinical medicine.
population medicine
According to Hill's criteria of causality, what are the contradictions to specificity?
one-to-one causation is unusual, since many diseases have more than one causal factor
quasi-experimental studies (community interventions) are often the ___________________________.
only types of intervention studies that can be conducted
A variable measured on an _________________ consists of items that are ordered (ranked) into mutually exclusive categories, however the differences between categories cannot be considered to be equal
ordinal scale
Proportions can also be expressed as ____________.
percentage
Descriptive epidemiology classifies the occurrence of disease according to the variables of _______________________________.
person, place, and time.
Epidemiologists have many forms of expertise germane to ____________________.
policy development
__________________________ is the number of of infant deaths form 28 days to 365 days after birth divided by number of live births minus neonatal deaths during a year.
postneonatal mortality rate
What single demention can be used to define socioeconomic status (SES)?
poverty level
What is an example of an odds ratio?
presence-to-absence ratio of cigarette smoking in those who had an MI compared with the same ratio in those who did not have an MI
What kind of study is the cross-sectional study?
prevalence study/survey in which exposures and outcomes measured at the same time and compares prevalence of disease in persons with and without the exposure of interest
Diseases are not as predictable as deterministic causality makes it seem, therefore ________________ is preferred.
probabilistic causality
What is the main component of community intervention quasi-experimental designs?
program evaluation- Used to determine whether the program meets stated goals and is justified economically
A ___________ is a type of ratio in which the numerator is part of the denominator and informs us the fraction of the population this is affected.
proportion (P= A/A+B)
A positive correlation scatter plot is r=?
r= 0.7
What factors are directly related to maternal mortality?
race, insufficient healthcare access, social disadvantage/health issues
What is an example of probabilistic causality?
radon exposure and probability of lung cancer- the greater the amounts of exposure the greater the probability of cancer induction
The difference between the sample statistic and the population parameter is known as ________________.
random sampling error
The sample should always be drawn ______________.
randomly
A _________ is also a type of ratio but it differs from a proportion because the denominator involves a measure of time.
rate
A __________ is defined as the value obtained by dividing one quantity by another so it is a fraction but does not necessarily have a specified relationship between the numerator and denominator.
ratio
A variable measured on an interval scale consists of items in mutually exclusive categories with equal distances between values and a meaningful zero point is a _______________.
ratio measurement
The ________________ is the population from which cases of a disease have been taken.
reference population
A _________ is the document used to collect the information.
register
A ___________ is a centralized database for collection of information about a disease that is used to track patients and to select cases for case-controlled studies.
registry
The line of best fit is also called the __________________.
regression line
The more narrow the confidence interval the more precise the ____________________.
relative risk
A proportion or percentage indicates how important a health outcome is ___________________________.
relative to the size of a group
Theories guide ____________ and ______________ tests and modified theories.
research, research
Quality of exposure assessment determines the accuracy of ________ assessments
risk
A _______________ is an exposure that is associated with a disease, morbidity, mortality, or adverse health outcome.
risk factor
What are rates used to measure?
risks associated with exposures providing information about the speed of development of a disease
Statistics can only estimate population parameters and the error of estimation is known as ____________________.
sampling error
A ______________ consists of a list of people from the accessible/source population from whom the sample can be drawn.
sampling frame
SPSS treats interval and ratio data as one category ________.
scale
How is the quality of epidemiological data determined?
the efficacy of the source used to obtain the data and how completely the data covers the reference population
What is wish bias?
similar to reporting bias, it may occur among subjects who have developed a disease and seek to show that the disease "is not their fault."
What are some public health related laws and regulations?
smoke-free bar laws, trans-fat rules, Bisphenol A (BPA) rules
According to Hill's criteria of causality, what are the contradictions to biological gradient?
some associations show a single jump (threshold) rather than a "best-fit line" trend
A _____________ is a statistic referring to a particular subgroup of the population defined in terms of race, age, or sex.
specific rates
A noncausal relationship is __________________ if there is a positive association but it is not what it purterm-62ports (false or fake).
spurious
A normal distribution in which all values are given as z-scores is called a ____________________________.
standard normal distribution
Epidemiologists employ ___________________________ to assess the degree to which chance may have accounted for observed associations.
statistical procedures
Probabilistic causality has ____________ causes.
stochastic
Probabilistic causality involved a probabilistic model and is also called a _________________________.
stochastic model
What is Hills nine criteria that need to be considered in the assessment of a causal association between exposure and outcome?
strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment, analogy
What does evidence-based public health refer to?
the adoption of policies, laws, and programs that are supported by empirical data
When conducting a decision analysis policy makes select what ideal alternatives?
the alternatives that minimize health risk and maximize desirable health outcomes and other benefits (unlike TX right now )
What are the possible appropriate uses of data?
the data may be used only for cross-sectional analyses but is primarily used for Case-control studies, Information about the incidence of disease, and Assessing risk status
What is risk characterization?
the development of estimates of the number of excess unwarranted health events expected at different time intervals at each level of exposure
What is hazard identification or hazard assessment?
the examination of evidence that relates exposure to an agent with its toxicity and produces a qualitative judgment about the strength of that evidence that is derived rom human epidemiology or extrapolated from laboratory animal data
According to Hill's criteria of causality, what are the contradictions to temporality?
the existence of an appropriate time sequence can be difficult to establish
According to the probabilistic model a cause is associated with _________________________________ that an effect will happen.
the increased probability
What are hazards?
the inherent capability of an agent or a situation to have an adverse effect on health
What is operationalization?
the process of assigning a precise method for measuring a term being examined for use in a particular study, Refers to the process of defining measurement procedures (terms) for the variables used in a study Oftentimes variables are defined conceptually (common journal article definition) and operationally (what the mean in the specific study)
What do cross-sectional studies examine?
the relationship between diseases (or other health-related characteristics) and other variables of interest as they exist in a defined population at one particular time- Snapshot of the health status of a study group (hopefully a randomly selected from the population) at a certain point in time
In an epidemiologic study what is bias?
the systematic deviation of the results or inferences from the truth. bias impacts the study procedures and can be particularly meaningful in epidemiology
What is external validity?
the target population that the sample is supposed to represent does represent them. Do the results of the study apply ("generalize") to people who were not in it?
What is the purpose of an epidemiological study?
to generalize the findings beyond the particular test group
What is the primary goal of epidemiology?
to measure relationships between "exposures" and health outcomes to provide a basis for public health initiatives and policies
What is the health services use of epidemiology?
to study the working of health services and improve to provide the optimum utilization of such services by helping to provide quantitative information regarding the availability and cost of healthcare services
Exposure is usually a risk factor for a disease, but it could also be a ___________.
treatment.
T/F One of the most reliable forms of evidence comes from randomized controlled trials.
true
T/F If the CI straddles 1.0, there is no significant increased or decreased risk.
true; there is no real difference in outcome, there is no relative risk its not meaningful or significant
Researchers conducting a retrospective cohort study are trying to establish...?
try to establish whether the people were exposed or unexposed based on prior records or the participants themselves. The researchers identify and enroll participants after the outcomes have occurred and then go back in time to check on exposure status.
What is multivariate or multiple causalities?
types of causal relationships that are involved with the etiology of diseases involve more than one causal factor
For most biologic effects, the components of a sufficient cause complex are _________________.
unknown
A "______" statistical association implies internal validity.
valid
What is big data? Where is it collected from?
vast electronic storehouses of information- cover very large numbers of people or even entire populations; internet search transactions, social media actives, data from health insurance programs, EMR from receipt of healthcare services
Why is non-probability convenience sampling problematic?
volunteers are more likely to be nonsmokers, more concerned about their health, more educated, employed in professional and skilled jobs, Protestant or Jewish, living in households with children, active in community affairs which fails to represent the larger population
In a crossover design the participants may be switched between treatment groups but must go through a _______________________.
washout period
What aspects of health do public health policies apply?
water quality, food safety, health promotion, environmental protection
What does a 95% confidence interval mean?
we are 95% sure that between the lower and upper bounds of the interval we have the population parameter of whatever it is we are checking out
When working with Pearson correlation coefficients (r) ranging from -1 to +1, the closer to zero, the _____________________.
weaker the relationship