In a prospective cohort study examining the relationship between occupational asbestos exposure and mesothelioma, 5,000 exposed workers were followed for 20 years. Of 200 who developed mesothelioma, 180 were exposed. Among 10,000 unexposed controls, 40 developed mesothelioma. The Attributable Risk Percent (Etiologic Fraction) in the exposed group is:
- A 80%
- B 88%
- C 90% ✓
- D 95%
Correct answer: C. 90%
Explanation
Attributable Risk Percent (ARP) in the exposed = (RR - 1)/RR × 100. Incidence in exposed = 180/5000 = 0.036; incidence in unexposed = 40/10000 = 0.004. RR = 0.036/0.004 = 9. ARP = (9-1)/9 × 100 = 8/9 × 100 = 88.9% ≈ 90%. This represents the proportion of mesothelioma cases in exposed workers attributable to asbestos exposure. Options A and D are incorrect as they don't match the RR calculation; 88% is close but the exact value rounds to 90%.
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.