A large prospective cohort of 20,000 adults has stored baseline serum samples and detailed exposure records. Over 15 years, 300 participants develop pancreatic cancer. Researchers select all 300 cases and 600 cancer-free participants matched on age and sex from the same cohort, and assay their stored sera for a biomarker. This design is:

• A Nested case-control study ✓
• B Case-cohort study
• C Historical prospective cohort study
• D Case-crossover study

Explanation

B nested case-control study is conducted entirely within an identified cohort: cases are incident cases arising during follow-up and controls are sampled from those still under observation at the time each case occurs. Its key strength is that exposure data predate disease onset, eliminating recall bias, while costing far less than assaying the entire cohort. B case-cohort study samples controls from the whole baseline cohort irrespective of later outcome, without incidence-density matching.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.