In a cohort study of 500 exposed and 500 unexposed individuals followed for 5 years, 50 exposed and 20 unexposed developed the outcome. What is the Attributable Risk Percent (AR%) in the exposed?
- A 40%
- B 60% ✓
- C 150%
- D 50%
Correct answer: B. 60%
Explanation
Incidence in exposed = 50/500 = 0.10; incidence in unexposed = 20/500 = 0.04. Attributable Risk = 0.10 – 0.04 = 0.06. AR% = (AR / Incidence in exposed) × 100 = (0.06/0.10) × 100 = 60%. This means 60% of disease in the exposed group is attributable to the exposure.
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.