What is a cohort study primarily used for in epidemiology?

• A. To test the effectiveness of a new drug
• B. To determine the incidence of disease among exposed and non-exposed individuals
• C. To diagnose specific health conditions
• D. To analyze the genetic composition of a population

Answer: (B)

A cohort study is a type of observational study design that is primarily employed to understand the relationship between exposures and outcomes over a specified period. In epidemiology, cohort studies are particularly valuable for determining the incidence of disease, which refers to the number of new cases that arise in a population during a specified time frame.

By comparing individuals who have been exposed to a certain risk factor or intervention with those who have not been exposed, researchers can assess how the presence or absence of that exposure affects the likelihood of developing a disease. This approach allows epidemiologists to establish temporal relationships and potential causal links, as well as to quantify the risk associated with particular exposures.

The other options focus on different aspects of medical research that do not align with the primary purpose of a cohort study. Testing the effectiveness of a new drug typically involves randomized controlled trials, which can establish causality more effectively than observational studies. Diagnosing specific health conditions is more aligned with clinical assessments rather than a study's design focus. Analyzing the genetic composition of a population is usually conducted through genetic studies and does not specifically pertain to the cohort study's primary function in epidemiology.