During a village cholera outbreak investigation, the attack rate in those who ate food at a community feast is 18/120 and in those who did not eat at the feast is 2/80. What is the Relative Risk (RR) of developing cholera with feast attendance?
- A 3.0
- B 9.0
- C 6.0 ✓
- D 12.0
Correct answer: C. 6.0
Explanation
Risk in feast-attendees = 18/120 = 0.15; risk in non-attendees = 2/80 = 0.025. RR = 0.15/0.025 = 6.0. An RR of 6 means feast attendees were 6 times more likely to develop cholera than non-attendees, strongly implicating the feast as the common source. The Attributable Risk = 0.15 − 0.025 = 0.125 (12.5 per 100), and Attributable Risk Percent = (0.125/0.15) × 100 = 83.3%.
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.