The death rate per 100,000 for lung cancer is 7 among non-smokers and 71 among smokers. The death rate per 100,000 for coronary thrombosis is 422 among non- smokers and 599 among smokers. The prevalence of smoking in the population is 55%. The relative risk of dying for a smoker compared to a non-smoker is: [Refer to the chapter titled “Study Designs: Cohort Studies”]
If it is accepted that an observed association is a causal one, an estimate of the impact that a successful preventive program might have can be derived from:
True or False? The term attributable risk is also known as the rate difference or risk difference.
A causal association between factor and outcome can refer to
When assessing a positive relationship between alcohol consumption and oral cancer using a case-control study, increasing the sample size of the study will result in which of the following?
Assuming that the sample table is for a cohort study, define the risk difference or attributable risk:
The population etiologic fraction is a measure of the proportion of the disease rate in a population attributable to the exposure of interest. This measure of effect is influenced by:
True or False? The term attributable risk is defined as the ratio of the incidence of a disease among exposed individuals to the incidence among non-exposed individuals.
The death rate per 100,000 for lung cancer is 7 among non-smokers and 71 among smokers. The death rate per 100,000 for coronary thrombosis is 422 among non-smokers and 599 among smokers. The prevalence of smoking in the population is 55%.
On the basis of the relative risk and etiologic fractions associated with smoking for lung cancer and coronary thrombosis, which of the following statements is most likely to be correct?
The death rate per 100,000 for lung cancer is 7 among non-smokers and 71 among smokers. The death rate per 100,000 for coronary thrombosis is 422 among non- smokers and 599 among smokers. The prevalence of smoking in the population is 55%.
The population etiologic fraction for a particular disease from Factor X alone is five times greater than that from Factor Y alone. If the relative risk associated with Factor X is 2, and with Factor Y is 20, which of the following statements is true?
In a study to determine the incidence of a chronic disease, 150 people were examined at the end of a three-year period. Twelve cases were found, giving a cumulative risk of 8%. Fifty other members of the initial cohort could not be examined; 20 of these 50 could not be examined because they died. Which source of bias may have affected the study?
A double-blind study of a vaccine is one in which:
The purpose of a double-blind study is to:
An epidemiologic experiment is performed in which one group is exposed to a suspected factor and the other is not. All individuals with an odd hospital admission number are assigned to the second group. The main purpose of this procedure is to:
In a survey which uses lay interviewers to interview one person about his or her health and the health of household members, the sources of error include:
The strategy which is not aimed at reducing selection bias is:
True or False? The purpose of matching in a case-control study is to select the controls in such a way that the control group has the same distribution as the cases with respect to certain confounding variables.
You are investigating the role of physical activity in heart disease and suggest that physical activity protects against having a heart attack. While presenting these data to your colleagues, someone asks if you have thought about confounders such as factor X. This factor X could have confounded your interpretation of the data if it:
Which of the following is not a method for controlling the effects of confounding in epidemiologic studies?