CHS 712.7001 Epidemiology in Public Health Final

Magnitude of confounding can be estimated by which equation?

(Crude RR - Adjusted RR)/Adjusted RR

Which study designs begin with people who have a disease?

- Case-control - Therapeutic trial

Which of the following study designs are considered observational studies? (Choose all that apply.) - Cohort study - Cross-sectional study - Clinical trial - Case-control study - Experimental study - Ecologic study

- Cohort study - Cross-sectional study - Case-control study - Ecologic study

Which measures of disease frequency focus on measuring the transition from health to disease?

- Cumulative incidence - Incidence rate

What are the major goals of randomization?

- Ensure treatment assignment occurs in an unbiased way. - Distribute potential confounders evenly across the groups.

Arrange the eras of epidemiology into the correct chronological order. - Era of sanitary reform - Era of infectious disease epidemiology - Era of chronic disease epidemiology - Emergent Era

- Era of sanitary reform (Late 1800s) - Era of infectious disease epidemiology (Early 1900s) - Era of chronic disease epidemiology (Late 1900s) - Emergent Era (21st Century)

Components of Epidemiology:

- Frequency and Distribution - Population - Disease Control - Disease Determinants

"Determinants" of disease include:

- Genetic make up - Causes of disease - Preventive factors

What is true about intent-to-treat analysis?

- Individuals allocated to a treatment are analyzed as representing that treatment, even if they did not actually complete the treatment. - It preserves the baseline comparability of groups. - It provides information on the effectiveness of a treatment under real-life conditions.

Match each era with its causal paradigm. - Era of sanitary reform - Era of infectious disease epidemiology - Era of chronic disease epidemiology - Emergent Era

- Miasmatic causes of disease - Causes, consequences, prevention - Web of causation - Eco-epidemiology, globalism

Describing disease by person, place, and time is done for what kind of purposes?

- Scientific - Administrative

Epidemiologic surveillance includes which of the following?

- Systematic collection of data - Analysis of data - Dissemination of data

Experimental studies can be classified by:

- The unit to which the treatment is assignment - Method of treatment administration - Purpose - Number of treatments being tested

Self-selection bias in a case-control study may occur if refusal or nonresponse is related to: A. case status B. exposure status C. case status and exposure status

...

If you wanted to read about the life expectancy of males and females in the U.S. population, which would be a likely source of this information? (Multiple choice) A. Health, United States B. National Health and Nutrition Examination Survey (NHANES) C. National Health Interview System (NHIS)

1. Health, United States

Important reasons to conduct surveillance on a regular basis include: (Select all that apply)

1. to establish a baseline in the community. 2. to identify an outbreak in the community. 3. to monitor disease trends. 4. to collect data for a case-control study.

In a population of 5,000 people, 100 ate spinach contaminated with E. coli (O157:H7) and became ill. Of the ill, 15 died. What was the case fatality rate?

150 per 1,000

In a study, the mixing of effects among the exposure, outcome, and a third factor related to the exposure and outcome is called: A. Confounding B. Random Error C. Bias D. None of the above

A. Confounding

If the diagnostic criteria of a disease were to change and become stricter than the previous criteria, what would you likely see in the data on this disease? (Multiple choice) A. Incidence would decrease B. Incidence would remain the same

A. Incidence would decrease

In the United States, a graph of the relationship between age and mortality rate is: (Multiple choice) A. J-shaped. B. normally distributed.

A. J-shaped.

If the True RR is 2.0 and the Adjusted RR is 3.0, confounding is said to be: A. Positive B. Negative C. Equal

A. Positive

One way to reduce the possibility of self-selection bias in a case-control study is to: A. obtain high participation rates among cases and controls B. ask about case status before enrolling a participant C. all of the answers D. ask about exposure status before enrolling a participant

A. obtain high participation rates among cases and controls

Unless resources are unlimited, the optimum ratio of cases to controls is: A. 1:8 B. 1:4 C. 1:2 D. 1:3

B. 1:4

What is one way to reduce the possibility of selection bias in a case-control study? A. Ask about exposure status before enrolling a participant. B. Use the same criteria to select cases and controls C. Ask about case status before enrolling a participant. D. Enroll the same numbers of controls as cases.

B. Use the same criteria to select cases and controls

Recall bias can occur in any study design, but it is most common in: A. ecologic studies. B. case-control studies. C. cross-sectional studies. D. cohort studies

B. case-control studies

An important work that helped mark the transition from the Social Reform Era to the Infectious Disease Era was the:

Bradford-Hill Criteria

Which of the following is one of the types of evaluation research discussed in the text? A. Stratified random efficiencies B. Needs case-controls C. Basic research D. None of the other answers

C. Basic Research

What is the term for a systematic error that is introduced in the study design or the way it is conducted? A. Confounding B. Random Error C. Bias D. None of the above

C. Bias

The crude death rate can be expressed as: A. the number of deaths divided by the population-at-risk. B. a weighted sum of the age-specific death rates and the proportions of the population by age. C. Both of these answers are correct.

C. Both of these answers are correct.

What are the two major forms of bias in a study? A. Confounding and prejudice B. Selection bias and prejudice C. Selection bias and information bias D. Information bias and prejudice

C. Selection bias and information bias

If you want to find data on global cancer incidence, which would be a likely source of this information?

Cancer Incidence on Five Continents

When the International Classification of Disease (ICD) is revised, deaths from a specific cause tend to:

Cannot tell without knowing more

Which study design would be most useful for studying the risk of a myocardial infarction immediately after exposure to heavy exertion?

Case-crossover study

Recall bias in a case-control study is introduced when:

Cases recall exposure differently from controls

Which study type is the typical design for measuring incidence?

Cohort

One way to minimize confounding by indication is:

Comparing treatments for the same condition

Repeated observations of a relationship between an exposure and outcome is an example of which of Hill's criteria?

Consistency

Which study design is most often used for public health planning?

Cross-sectional

Homogeneity of effect means: A. effect measure modification is absent. B. the stratum-specific measures of association between an exposure and outcome are nearly the same for each stratum of a third variable. C. statistical interaction is absent. D. All of the above

D. All of the above

Some ways to minimize misclassification bias include: A. validating collected data B. defining exposure and disease using sensitive and specific criteria C. using multiple measures of exposure and disease D. All of the above

D. All of the above

Which of the following should be considered as an alternative explanations for the results of a study? A. Random Error B. Confounding C. Bias D. All of the above

D. All of the above

Which of the following should be considered as an alternative explanations for the results of a study? A. Bias B. Confounding C. Random Error D. All of the above answers

D. All of the above answers

The criteria of a confounder includes: A. an association with the exposure in the population that produced the cases. B. an independent risk factor for the outcome of interest. C. that it cannot be an intermediate step in the pathway between the exposure and disease. D. All of the answers

D. All of the answers

Vital statistics refers to the collection of information about: (multiple choice) A. Divorces and marriages B. Births and deaths C. Fetal deaths D. All of these

D. All of these

The main purpose of adjusting death rates for age is to: A. compare mortality across different populations. B. control for differences in the age distributions of populations. C. eliminate the effects of age when comparing populations. D. All of these answers are correct.

D. All of these answers are correct.

What is a common problem of ecologic studies?

Ecologic fallacy

If there is no relationship between exposure and disease, then the relative measure would be:

Equal to 1.0

Some uses of a case-control study include which of the following activities?

Evaluating preventive measures. Investigating disease outbreaks. Evaluating the effectiveness of vaccines.

What was the signal event of the transition from the era of infectious disease epidemiology to the era of chronic disease epidemiology?

Evidence that smoking caused lung cancer

When comparing members of a population on the presence or absence of a characteristic, the group with the characteristic is called the:

Exposed or index group

A risk factor is always the same thing as a cause.

False

Cross-sectional studies evaluate associations using the population rather than the individual as the unit of study.

False

Differential misclassification always leads to bias toward the null.

False

Epidemiologist agree on the specific steps in the method of causal inference.

False

Epidemiologists can tell if confounding is present by examining the strength of the crude measure of association.

False

Generalization of study results to other populations is more important than establishing the internal validity of a study.

False

Hill's causal criteria should be used systematically as rigid criteria for establishing causal inference.

False

In a case-control study, it is better to include people who may not have the disease than to exclude people who do have the disease.

False

It is always impossible to infer temporality from a cross-sectional study.

False

Pancreatic disease is suitable for screening because it is a serious condition.

False

Prevalence is most useful for determining the rate and cause of disease.

False

Secondary prevention efforts include activities that prevent onset of disease.

False

The best way to evaluate effect measure modification is to compare the crude measure of association and the adjusted measure of association.

False

The criteria for case definitions are different in case-control studies than in other types of epidemiologic studies.

False

The direct method of standardization is used when the numbers of deaths in each age group in the study population are too small to calculated stable age-specific rates.

False

Therapeutic and preventive trials take approximately the same amount of time to complete.

False

When examining surveillance data by place, it is better to characterize cases by the place where they were reported rather than by the place of exposure.

False

Major advantages of a case-cross-over study are which of the following?

Fewer subjects are needed Cases and controls have similar characteristics It is easier to get controls

People who volunteer for clinical trials tend to be different from people who do not volunteer. What effect would this have on a study?

Generalizability of the results

An important work that helped mark the transition from the Social Reform Era to the Infectious Disease Era was the:

Henle-Koch Postulates

The population rate difference describes the excess number of cases:

In the population, caused by the exposure

Which measure of incidence has person-time in the denominator?

Incidence rate

The classic analysis for an experimental study is:

Intent to treat

One of the earliest experimental studies on scurvy was conducted by:

James Lind

Who conducted a thorough analysis of the water drinking habits to investigate the source of a cholera epidemic in London?

John Snow

What over-estimates benefits of screening and should be taken into account when evaluating a screening program?

Lead-time bias

If the exposure prevents the disease, then the relative measure would be:

Less than 1.0

If there is a negative relationship between the exposure and disease, then the relative measure would be:

Less than 1.0

What is the most common source of selection bias in a prospective cohort study?

Loss to follow-up

Which mortality rate is considered a sensitive indicator of the overall health of a population?

Mortality rate of infants

Which of the following is the principal source of data on the health of the civilian, non-institutionalized population of the United States?

National Health Interview Survey

A worldwide epidemic is referred to as:

Pandemic

Primary prevention efforts are targeted at the...

Pathological onset stage

Which of the following measures would tend to be larger in the same population?

Period prevalence

Spot maps are useful for presenting surveillance data by:

Place

In the natural history of disease, the period from the pathological onset of disease to the first appearance of signs and symptoms is referred to as the...

Preclinical stage

The main way to measure the feasibility of a screening program is with...

Predictive value

What do chronic diseases usually have?

Proximate and distant causes

One exposure causing one effect is an example of which of Hill's criteria?

Specificity

Evaluating an odds ratio describing the relationship between an exposure and outcome is an example of which of Hill's criteria?

Strength of association

If you wanted to find data on cancer incidence in the United States, which would be a likely source of this information?

Surveillance, Epidemiology and End Results System (SEERS)

Relative measures of comparison usually give information about:

The association between an exposure and outcome

What causes the "ecologic fallacy"?

The lack of information at the individual level

Line graphs are useful for presenting surveillance data by:

Time

"Statistical power" refers to the ability of a study to demonstrate an association if one exists.

True

A "sufficient cause" could also be described as one pathway for getting a specific disease.

True

All high-quality epidemiologic studies include techniques for controlling confounding.

True

An absolute measure of comparison is based on the subtraction of two frequency measures.

True

An age-adjusted death rate is a hypothetical index.

True

An alternative to intent-to-treat analysis is an efficacy analysis.

True

An important difference between an observational study and an experimental study is that exposures are assigned to participants in experiments.

True

Attack rate is a type of cumulative incidence.

True

Before a causal relationship between exposure and outcome can be considered, the internal validity of the study must be established.

True

Case fatality rate is a type of cumulative incidence.

True

Cohort studies compare exposed and unexposed, while case-control studies compare diseased and non-diseased.

True

Confounding may be accounted for in either the design of the study or analysis of the data.

True

Cut-points of screening tests should take into account the seriousness of false positives and false negatives.

True

Data from death certificates should be evaluated carefully because inconsistencies may occur when the International Classification of Disease (ICD) codes are changed.

True

Eligibility criteria affect the generalizability of an experimental study.

True

Epidemiologists may use either a visual inspection or a statistical test to evaluate effect measure modification.

True

Examination of a 2x2 table is important because formulas and interpretation may change based on whether exposure status is placed along the side (rows) or along the top (columns).

True

In confounding, we are interested in whether the measure of association is distorted by a third variable, whereas in effect measure modification, we are interested in whether the measure of association differs across levels of a third variable.

True

In the sufficient-component causal model, blocking one component in a "causal pie" could prevent the disease from occurring through that pathway.

True

It is not enough to determine the presence of confounding; an investigator must also determine the magnitude and direction of confounding.

True

John Snow's epidemiologic study of the cause of the London Cholera epidemic could be considered a "natural experiment."

True

John Snow's theories about the transmission of cholera were disputed for several years after conducting his famous study in London.

True

More than one phase of a new drug trial may be conducted at the same time.

True

Most epidemiologist consider Hill's criterion of "specificity" useless.

True

Non-differential misclassification of dichotomous variables biases results toward the null.

True

Nondifferential loss to follow-up of diseased participants in a cohort affects the absolute risk but not the relative risk.

True

Nondifferential loss to follow-up of diseased participants in a cohort study results in lower observed incidence of disease.

True

One indication that effect measure modification is present is that the size of a measure of association changes according to the level of a third variable.

True

Prevention trials may be classified as primary prevention trials or secondary prevention trials.

True

Sensitivity and Specificity are percentages.

True

Spot maps are helpful in showing the geographic distribution of cases but should not be used to assess the risk of disease.

True

Standardizing to a younger population results in a lower age-adjusted death rate.

True

Tertiary prevention efforts include activities that target people with existing disease.

True

The National Health Care Surveys are a group of surveys that provide information on the use and quality of health care in a number of different settings.

True

The best way to minimize bias from misclassification is to improve the accuracy of the collected data.

True

The denominator of prevalence includes people who are sick, healthy, at risk, and not at risk.

True

The odds ratio can be conceptualized as either a disease odds ratio or an exposure odds ratio.

True

The prevalence of a disease is related to the incidence rate and duration of the disease.

True

The rationale behind using dead controls in a case-control study is for comparability of data collection procedures between cases and controls.

True

When comparing death rates in the same population for different years, it is essential to adjust the rates to the same standard population before making a comparison.

True

When effect measure modification is present on a relative scale, it is absent on an absolute scale.

True

When researchers evaluate whether study results are true, they are really evaluating the internal validity of the study.

True

The primary disadvantage of passive surveillance is:

Under-reporting

For a case-control study, why is it not important that all cases in a population be identified?

Validity should not be sacrificed for generalizability Partial case ascertainment is legitimate as long as the source population can be identified

Of the early key figures in the history of epidemiology and demography, which one is credited for developing the British system for vital statistics?

William Farr

The lifetime risk of cancer. This measure of disease frequency is:

cumulative incidence.

The percentage of freshman girls who become pregnant over the course of their high school years. This measure of disease frequency is:

cumulative incidence.

The number of live-born babies who die of sudden infant death syndrome during the first year of life per 100,000 baby-years of follow-up. This measure of disease frequency is:

incidence rate

The detectable preclinical phase (DPCP) of a disease is a function of:

natural history of disease and capabilities of the screening test

The percentage of senior boys who are fathers at the time of graduation. This measure of disease frequency is:

prevalence proportion.

The best statistical test for effect measure modification is:

the chi-square test for homogeneity

Data from the U.S. Census are used:

to assign members of the House of Representatives to the states and to identify denominators for incidence and prevalence measures.