Combo with "651 Final"
% of women with BRCA 1 or 2 mutations who go on to develop breast cancer (prev, cum inc, inc den)
Cumulative incidence
In a case-control study, mothers of babies with birth defects are asked to recall exposures during pregnancy, such as taking nonprescription drugs. Given the stimulus of an adverse pregnancy outcome, these mothers recall vividly what they wondered might have caused the birth defect. Mothers of normal babies, however, have no stimulus for recall and thus forget such exposures. This particular version of recall bias is known as maternal recall bias. The maternal recall bias is an example of:
Differential misclassification of exposure
2 ways prevalence is different from cumulative incidence
Existing cases vs. new cases developed over time, Prevalence is always a proportion, incidence isn't always
Positive predictive values can be ONLY influenced by sensitivity and specificity of a screening (T or F)
False
the controls in a case-control study are selected to represent the entire non-diseased population? (t or f)
False (% of pop that the cases come from)
_________ cause is a component case that is a member of every sufficient cause
Necessary
% of babies who test positive for PKU at birth (prev, CI or ID)
Prevalence
The difference between primary and secondary prevention of disease is______?
Primary prevention means control of causal factors, while secondary prevention means early detection of disease.
Cumulative Incidence (rate, proportion, or neither)
Proportion
Prevalence (rate, proportion, or neither)
Proportion
Predictive values
Proportion of those tested who are correctly classified (as either cases or non cases)
Incidence density (rate, proportion, or neither)
Rate
A program using screening mammography for breast cancer is best regarded as
Secondary
A program using screening mammography for breast cancer is best regarded as (primary, secondary, or tertiary)?
Secondary
In a case-control study to examine risk factors for lung cancer, cases are admitted to hospital with lung cancer, and controls are people admitted to the same hospital with emphysema (a chronic lung disease for which smoking is a risk factor). The study finds no association between smoking and lung cancer. Identify which type of bias might be introduced
Selection bias
A cohort study examined the association between smoking and lung cancer after following 400 smokers and 600 non-smokers for 15 years. At the conclusion of the study the investigators found a risk ratio = 17. What is the interpretation of this risk ratio?
Smokers had 17 times the risk of lung cancer compared to non-smokers in this study
what is true about a ratio measure that is less than 1.0?
There is a possible protective (negative) association between the exposure and the health outcome
a study is done to examine whether there is an association between use of multivitamins and risk of coronary artery disease. COmared to people who do not take vitamins, individuals who do have a relative risk of 0.7. What is the interpretation of this finding?
Those who take daily multivitamins have 0.7 times the risk of heart attack compared to those who do not take vitamins
when prevalence of disease is much greater than the incidence, the duration of the disease may be long and case fatality may be low (t r F)
True
Specificity
True negatives (non cases identified)/all cases -how often non cases will be identified with this test d/b+d
Negative predictive value
True negatives (non-cases)/All negatives d/c+d
Sensitivity
True positives (cases found)/All cases -how often cases will be identified with this test a/a+c
Positive predictive value
True positives (cases)/all positives a/a+b
study of 2477 subjects for cataracts found that 310 had them. What is the prevalence of cataracts?
.125
In a study, you observed an incidence rate ratio of 0.90 (95% CI: 0.85-1.10) between an exposure and a disease, what would the P value for the association be:
>.05
Several studies found that approx. 85% of lung cancer cases in smokers are due to cigarette smoking. this measure is an example of?
an attributable risk percent
Recommend that close contacts of a child recently reported with meningococcal meningitis receive Rifampin determinants, distribution, or application?
application
The public health impact of a successful preventative program is best measured by:
attributable risk or attributable risk percent
hallmark of cohort study design
begins with group of exposed people and compares to non-exposed group
hallmark of case-study design
begins with people who have the disease (case) and compares to those without (control)
a study of multiple occurrences of unusual cases that have similar characteristics. Investigators can calculate the frequency of symptoms or characteristics of people with the disease. What kind of study?
case report
name the 3 descriptive epidemiological studies
case reports correlational studies cross-sectional studies
id type of study: authors describe characteristics and the outcome of a patient with a rare disease
case study
the authors describe the characteristics and the outcome of a patient with a very rare disease. what kind of study design?
case-report
Epidemiology by outcome
chronic disease (cancer, cardiovascular) infectious disease (outbreaks) psychiatric
Explain how you would assess whether a potential confounder alters an effect estimate after adjusting for it in a multivariate model.
compare crude RR to adjusted RR
Explain how you would evaluate whether confounding affects an effect estimate
compare the crude OR to the adjusted OR
_____ cause is any one of a set of conditions which are necessary for the completion of a sufficient cause
component
any one set of conditions which are necessary for the completion of a sufficient cause= ______cause
component cause
A case-control study was undertaken to evaluate the relationship between maternal smoking during pregnancy and low birth-weight. It was observed that mothers of low-birth weight babies tended to be older than the mothers of the normal-weight babies. Moreover, smoking rates are known to be higher in younger women in this population. This would be an example of
confounding
In a cohort study, investigators observed that postal clerks who worked in the office had higher rates of coronary heart disease than postal carriers who delivered mail on foot (RR=2.0; p<0.05). They concluded that physical activity was inversely related to risk of developing coronary heart disease. Skeptics disagreed, pointing out that the postal clerks were heavier than the postal carriers, and that obesity is independently related to risk of heart disease. This argument is an example of
confounding
In the same study, it was also observed that mothers of low-birth weight babies tended to be younger than the mothers of the normal-weight babies. Moreover, smoking rates are known to be higher in younger women in this population. This would be an example of the effects of
confounding
id type of study: study looked a prevalence of obesity among IU students during fall 2015
cross sectional
a study looked at the prevalence of obesity among IU students in the fall of 2015. what kind of study design?
cross-sectional
What is a study design called when studying one or more variables within a given population at one point in time?
cross-sectional study
what study design is sometimes referred to as a "snapshot in time"?
cross-sectional study
The average lifetime risk of developing pancreatic cancer is 1 in 67 (1.5%). This is what measure of disease frequency?
cumulative incidence
In a case-control study, what effect (if any) would you expect if the interviewers were aware of the disease status of the study subjects?
damage validity by introducing interviewer bias
If the sample size (in a case-control) study is doubled, the width of the 95% CI of OR estimate is expected to: increase or decrease
decrease
A placebo would be used in a randomized controlled trial to
decrease information bias
as the sample size increases CI does what?
decreases
and sample size increases p value does what?
decreases, becomes more precise
Compare food histories between persons with Staphylococcus food poisoning and those without, and investigate whether a specific food is linked with the disease. determinants, distribution, or application?
determinants
Compare frequency of brain cancer among anatomists with frequency in general population, and investigate whether the anatomy practice is associated with brain cancer determinants, distribution, or application?
determinants
Mark on a map the residences of all children born with birth defects within 2 miles of a hazardous waste site determinants, distribution, or application?
distribution
Tabulate the frequency of clinical signs, symptoms, and laboratory findings among children with chickenpox in Cincinnati, Ohio determinants, distribution, or application?
distribution
describing the demographic characteristics of persons with diabetes in Bloomington, IN. What best describes the activity that an epidemiologist might perform based on the definition of epidemiology? determinants, distribution, or application
distribution
crude mortality rate does/does not use mid-year pop. as denominator
does not
a study was to evaluate the association between motorcycle licensing and operation regulations and motorcycle mortality rates at state level in the US, what kind of study was this?
ecologic or correlational
the authors compare mortality due to cardiovascular disease between countries with different gross national products using a graph What kind of study design is this?
ecologic or correlational
Id type of stdy: compare mortality due to cvd between counties with different gnp sing a graph
ecologic/longitudinal
ascribing the characteristics of a group to every individual in that group
ecological fallacy
international comparison of prostate cancer mortality rates with dietary practices and sunlight levels. What kind of study?
ecological or correlational
infectious disease spreads rapidly through a population
epidemic
Recall bias always results in an underestimate of the magnitude of association. The statement is true or false.
false
descriptive epidemiology tests the hypothesis regarding determinants of disease t or f
false
a ratio measure of association expresses the prevalence, risk or rate among exposed in EXCESS of that among the unexposed or less-exposed? t or f
false (bc ratio does not measure excess, only difference does)
both prevalence and incidence rate are proportion
false (incidence is not proportion,it's a rate, time component)
We calculate the relative risk directly in case-control study? t or f
false (odds ratio for case-control bc you don't have the direct rates, only estimating)
validity
get the correct result
The overall rate of death from cardiovascular disease was 236.1 per 100,000 person-years in 2009 in the U.S. This is an example of what measure of disease frequency?
incidence rate
# of rollerblading injuries per 100 person-months of observation (Prev, Ci or id)
incidence rate (density)
In designing a case-control study, selection of controls should be: dependent or independent of exposure of interest?
independent
In a case-control study, what potential problem could have been introduced if you found out that interviews with cases took 30 minutes longer than interviews with controls
information bias
What potential bias could have been introduced if you found out that those who interviewed cases took 30 minutes longer on average than those who interviewed controls?
information bias
A placebo would be used in a randomized intervention study to decrease what bias?
information/observation
In a case-control study, what would have happened if interviewers were aware of the disease status of the study subjects
interviewer bias, it would cause damage
if incidence goes up and duration goes down, what happens to prevalence?
it goes down
if incidence goes down and duration goes up, what happens to prevalence?
it goes up (change in duration = increase in prevalence bc lower deaths but people are not cured, so they stay prevalent longer) tx but no cure, ppl living longer w/disease
If the average length of survival from childhood leukemia continues to remain the same, but the prevalence of childhood leukemia increases. what has happened to incidence?
it has increased
What are the approaches to handle confounding?
matching multivariate analysis stratification
epi by populations
maternal and child health clinical occupational veterinary
Two pediatricians want to investigate a new laboratory test that identifies streptococcal infections. Dr. Kidd uses the standard culture test, which has a sensitivity of 90% and a specificity of 96%. Dr. Childs uses the new test, which is 96% sensitive and 96% specific. If 200 patients undergo culture with both tests, which of the following is correct? Dr Childs will correctly identify (more, fewer, or same number) of people with streptococcal infection as Dr. Kidd?
more
a component cause that is a member of every sufficient cause____ cause
necessary cause
A cohort study of the risk of liver cirrhosis among female alcoholics. Incidence rates of cirrhosis among alcoholic women are compared to those among nonalcoholic women. Nonalcoholics are individually matched to alcoholics on month and year of birth. Is age a confounder in this study?
no
A study of the relationship between exercise and heart attacks that is conducted among men who do not smoke. Is gender a confounder in this study?
no
Does one need to specify the time units for risk ratio?
no
2. A case-control study was conducted to determine if using antihistamines around the time of conception increased the risk of birth defects in the offspring. No personal interviews were conducted regarding the subjects' antihistamine use. Instead, women were considered exposed if computerized pharmacy records from their health maintenance organization indicated that they had filled at least one prescription for antihistamines within 500 days before the birth of the child. Which type of information bias is this data collection method most susceptible to?
nondifferential misclassification of the exposure
epidemiology by exposure
nutrition environmental behavioral
in a case-control study, what measurement can you calculate to estimate the relative risk for the association between disease and exposure?
odds ratio
global epidemic, when a disease spreads across the globe
pandemic
descriptive epidemiology describes the general characteristics of disease distribution with respect to
person, place, and time
the width of the CI reflects the _________ of the estimate
precision
Successful treatment programs that would shorten the duration of a disease primarily affect:
prevalence
in 2012, 9.3% of the US population had diabetes. This is what measure of disease frequency?
prevalence
proportion of children who have asthma in the beginning of 2015 (prev, cum inc, or inc density/rate)
prevalence
successful treatment programs that would shorten the duration of a disease primarily affect
prevalence
what measure of disease frequency is used for cross-sectional studies?
prevalence
Counseling about reducing risk for sexually transmitted infection is an example of _(primary/secondary/tertiary)__ prevention.
primary
recommending regular physical activity to an individual with no known medical problem (primary, secondary or tertiary prevention)
primary
vaccinating a health care worker against hepatitis B (primary secondary or tertiary prevention
primary
absolute measurement provides information about _____ of an exposure
public health impact
In evaluation of this study, it was suggested that smoking mothers of low-birth weight babies would tend to deny such an activity due to feelings of guilt more than mothers of normal-weight babies. This would be an example of the effects of
recall bias
The following statement is an example of what measure of association? The excess risk of breast cancer among statin users is "x" over the study period, compared to non-statin users.
risk difference
When public health officials are interested in determinng the number of cases which could possibly be prevented by eliminating a risk factor, which measure of association would they be interested in?
risk difference
reliability
same result every time (repeatability)
A program using screening mammography for breast cancer (primary, secondary, tertiary)?
secondary
A case-control study was undertaken to evaluate the relationship between maternal smoking during pregnancy and low birth-weight. Of 300 mothers of low birth-weight babies, 100 reported smoking during the pregnancy. Of the 400 mothers of normal weight babies, 100 also reported smoking. When this case-control study was conducted, participation among cases was 80% and participation among controls was 50%. Thus the investigators were concerned about the possibility of
selection bias
An investigator would like to assess the association of melanoma (skin cancer) and exposure to infrared skin tanning services by using a hospital-based case-control study. Hospitalized individuals with melanoma will be compared with hospitalized patients without melanoma (controls). This hospital, located in a low-income area of the city, is famous nationwide for its expertise in melanoma. Individuals with melanoma (cases) from all over the country go to that hospital to get the highest quality care that can be provided. However, this hospital is not as well known for any other medical conditions as it is for melanoma. Therefore, cases would come from all over the country, and controls will be mostly local low-income individuals. Based on the information provided, what type of bias is this study most susceptible to?
selection bias
In a prospective cohort study, when drop-out rate is very high over the study period, what type of bias you may be concerned of ?
selection bias
other fields of epi
social pharmaco genetic molecular
Suppose that investigators wanted to determine if confounding was present during the analysis phase of the study. What can be done at the analysis phase of the study to look at confounding?
stratified analysis
______ cause is a set of minimal conditions of events that inevitably produce disease
sufficient
minimal conditions or events that inevitably produce disease= ______ cause
sufficient cause
It has been suggested that nurse practitioners may examine women who use oral contraceptives more often or more thoroughly than women who do not. If this is true, and if an association is observed between phlebitis and oral contraceptive use, the association may be due to what type of basis?
surveillance bias
It has been suggested that physicians may examine women who use oral contraceptives more often or more thoroughly than women who do not. If so, and if an association is observed between phlebitis and oral contraceptive use, the association maybe due to:
surveillance bias
Performing carotid endarterectomy in a patient with transient ischemic attack ( primary, secondary or tertiary prevention?)
tertiary
what does CI represent?
the range within which the true value lies with stated probability (if includes 1, then likely due to chance)
Relative measures of association (ex. IRR) provide information about:
the strength of exposure-disease association in the study population
In a study of a disease in which all cases that developed were ascertained, if the relative risk for the association between a factor and the disease is equal or larger than 1.0 then...
there is either no association (1.0) or a positive association between the factor and the disease ( > 1.0)
Interpret the meaning of an odds ratio of 1.00 for the association between consumption of fish oil and prostate cancer
there is no association between fish oil intake and prostate cancer
Assuming there is no association between an exposure and a disease, the observed relative risk between the exposure and disease may not be exactly equal to 1 because of chance. The statement is true of false.
true
Case-control studies are vulnerable to bias because both the exposure and disease have already occurred, and knowledge of disease status may influence reporting or recording of exposure status. The statement is true or false.
true
In a cohort study of the association between physical inactivity and diabetes, the stratum-specific rate ratio for their association is 1.8 for men and 1.8 for women. The overall crude rate ratio is 2.5. This example suggests that gender may be a confounder. t or f?
true
when the prevalence of a disease is similar to the incidence, the duration of the disease may be short and the case fatality may be high (t or f)
true
ecological fallacy is when incorrect inferences about the individual are made from group level data (t or F)
true (observations made at the group level may not represent the exposure-disease relationship at the individual level)
molecular epi
use of biological markers to examine parts of a continuum between an initiating event and the development of disease
in which circumstances can cross-sectional surveys be used to test hypotheses?
when exposure variable is unaltered over time
A case-control study of the relationship between cigarette smoking and pancreatic cancer. In this study, coffee drinking is associated with smoking and is a risk factor for pancreatic cancer among both smokers and nonsmokers. Is coffee drinking a confounder in this study?
yes
A study of the relationship between contact lens use and the risk of eye ulcers. The crude relative risk is 3.0 and the age-adjusted relative risk if 1.5. Is age a confounder in this study?
yes
is it possible to compute the attributable risk in the exposed from incidence rates?
yes
