A cohort study of smokers shows a relative risk of 5.0 for lung cancer. The baseline incidence in non-smokers is 0.004 per year. What is the attributable risk percent (etiological fraction) in the exposed group?
- A 50%
- B 80% ✓
- C 75%
- D 67%
Correct answer: B. 80%
Explanation
Attributable Risk Percent (ARP) in exposed = (RR − 1)/RR × 100 = (5 − 1)/5 × 100 = 80%. This means 80% of lung cancer in smokers is attributable to smoking itself. Option A uses (RR−1)/RR incorrectly, while C and D use different denominators.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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