What is the main difference between cohort studies and case-control studies? A.
ID: 3365051 • Letter: W
Question
What is the main difference between cohort studies and case-control studies? A. Cohort studies define subjects according to exposure level and follow them for disease occurrence; in case-control studies, investigators assign participants to their exposure groups B. Case-control studies define cases and controls and compare their exposure histories; in cohort studies, we collect exposure and outcome data at the same time C. In case-control studies, cases and controls are followed up over time to examine exposure history; in cohort studies, rates of disease by aggregate characteristics of a population are examined D. Cohort studies define subjects according to exposure level and follow them for disease occurrence; case-control studies define cases and controls and compare their exposure histories
Explanation / Answer
D. Cohort studies define subjects according to exposure level and follow them for disease occurrence; case-control studies define cases and controls and compare their exposure histories
The cohort study design identifies people exposed to a particular factor and a comparison group that was not exposed to that factor and measures and compares the incidence of disease in the two groups.
The case control design identifies a group of individuals who had developed the disease (the cases) and a comparison of individuals who did not have the disease of interest. The cases and controls are then compared with respect to the frequency of one or more past exposures.