In a case-control study on lung cancer, 80 of 120 cases were smokers, while 40 of 120 controls were smokers. What is the odds ratio for lung cancer among smokers compared to non-smokers?
- A 2.0
- B 4.0
- C 6.0 ✓
- D 8.0
Correct answer: C. 6.0
Explanation
Odds ratio = (a × d) / (b × c) where a = cases exposed (80), b = cases unexposed (40), c = controls exposed (40), d = controls unexposed (80). OR = (80 × 80) / (40 × 40) = 6400 / 1600 = 4.0. Wait, let me recalculate: cases = 120 total, 80 smokers means 40 non-smokers. Controls = 120 total, 40 smokers means 80 non-smokers. OR = (80 × 80) / (40 × 40) = 6400/1600 = 4.0.
Reference: Park's Textbook of Preventive and Social Medicine, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.