Examining historical height and weight records of a university freshman cohort to see if related to coronary heart disease developed by 1986 is an example of which study design?

• A. Cross-sectional
• B. Case-control
• C. Concurrent cohort
• D. Retrospective cohort

Answer: (D)

This question hinges on recognizing a retrospective cohort design. Here, a defined group—the university freshman cohort—is identified, and exposure data (height and weight) are pulled from historical records. The outcome (coronary heart disease) is then determined for those individuals by a fixed date (1986). The key is that both the exposure information and the disease outcome are gathered after the fact from existing records, with the cohort looked at as a whole rather than starting with people based on disease status.

This differs from:

• Cross-sectional approaches, which assess exposure and disease at a single point in time without establishing a temporal sequence.

• Case-control approaches, which begin with individuals who have the disease and compare past exposures to those without disease.

• Concurrent (prospective) cohort approaches, which follow a cohort forward in time from baseline to observe outcomes as they occur going forward.