Exam 5: Study Design

If increasing levels of exposure cause increasing levels of the outcome, we would say that there is evidence of biological plausibility when assessing causal inference.

What is the relative risk for throat cancer among smokers compared to non-smokers based on the numbers below?

We are using cross-sectional data to investigate whether heavy drinking increases the risk of unemployment. Which of the following aspects of causal inference concerns you based on this information?

The correct measure of excess risk to be used in case-control studies is the relative risk.

A cross-sectional study is one in which both exposure and outcome are assessed at the same point in time, providing a snapshot of experience rather than information over time.

Which of the following epidemiological study designs makes use of group-level rather than individual level) data?

An observational epidemiological study is one in which the researcher randomly assigns participants to an exposure group.

In order to investigate whether nutritional information combined with telephone counseling is better at increasing weight loss among women who are obese than telephone counseling alone, researchers randomly assign one group of obese women to the counseling only group and assign another group of obsess women to the counseling plus nutritional information group. What type of epidemiological study is this?

Bias is the ability to correctly identify cases people with the outcome) as cases in a case- control study.

The Framingham Heart Study, which has followed 3 generations of Framingham, Massachusetts since 1948 to assess the risk factors for heart disease and other health outcomes, is an example of what type of epidemiological study?

The following data are based on a study of 375 people sampled in the following way: 125 people who have been diagnosed with throat cancer and 250 people who have not been diagnosed with throat cancer were selected from hospital records. Among other exposures, these individuals with and without throat cancer were asked about their smoking history. What is this study design?

Making individual-level inferences about the relationship between exposure and outcome based on group-level data is called confounding.

If the results of your study are the opposite of most previous studies published, which aspect of causal inference should you be concerned about?

Observational studies are considered to be better than experimental studies because they are not plagued by confounding.

Data from the Behavioral Risk Factor Surveillance System - a telephone survey that asks adults about a variety of health behavior and health conditions at a single point in time - could be used for what type of epidemiological study?

If you calculate a relative risk of 1.0 RR=1.0) in a cohort study, what is the correct interpretation?

In both cohort studies and case-control studies, the crude) measure of excess risk can be calculated by setting up a 2x2 table.

A prospective cohort study is one that uses historical exposure information - for example, employment or medical records - to construct the exposed and unexposed groups.

One reason that observational studies are common in public health research is that many exposures in which we are interested are not ethical to assign people to experience like radiation, smoking during pregnancy, or being in a car crash).

A research team is interested in whether warfarin a medication to prevent clotting) reduces the risk of stroke. They ask warfarin's manufacturer for the number of annual warfarin prescriptions in the US from 1990-2000 and use data from death certificates to assess the numbers of deaths due to stroke in the US during the same time period. The resulting graph showed that the number of annual warfarin prescriptions increased in the US from 1990-2000 while stroke mortality in the US declined from 1990-2000. What type of study is this?