Which of the following study designs would provide the STRONGEST evidence regarding a rare adverse drug effect that occurs 1 in 10,000 exposures, when following up large cohorts is logistically impossible?

• A Prospective cohort study
• B Case-control study nested within a cohort ✓
• C Randomized controlled trial
• D Ecological study

Explanation

A nested case-control study within a defined cohort combines the efficiency of the case-control design (suitable for rare outcomes, smaller sample requirements) with the temporal clarity of a cohort, as exposure was measured before disease onset. Full cohort follow-up and RCTs would require prohibitively large numbers for a 1-in-10,000 event. Ecological studies cannot attribute exposure at the individual level, making them prone to ecological fallacy.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.