Which study design is typically used to examine exposure and disease by following exposed and unexposed groups over time?

Which study design is typically used to examine exposure and disease by following exposed and unexposed groups over time?

• A. Case-control study
• B. Cross-sectional study
• C. Ecological study
• D. Cohort study

Answer: (D)

Following exposed and unexposed groups over time to observe who develops the disease is the defining feature of a cohort study. This design starts with people categorized by exposure status and then tracks them forward (or uses existing records) to measure incidence of the outcome, which also lets us estimate risk and assess temporality between exposure and disease. Case-control studies begin with disease status and look back to determine prior exposure, rather than following exposure groups over time. Cross-sectional studies capture exposure and disease at a single point and don’t establish which came first. Ecological studies use group-level data and don’t follow individuals over time. So the approach that best fits the described scenario is the cohort design.

Following exposed and unexposed groups over time to observe who develops the disease is the defining feature of a cohort study. This design starts with people categorized by exposure status and then tracks them forward (or uses existing records) to measure incidence of the outcome, which also lets us estimate risk and assess temporality between exposure and disease. Case-control studies begin with disease status and look back to determine prior exposure, rather than following exposure groups over time. Cross-sectional studies capture exposure and disease at a single point and don’t establish which came first. Ecological studies use group-level data and don’t follow individuals over time. So the approach that best fits the described scenario is the cohort design.