A case-control study examines smoking and oral cancer. Among 50 cases, 40 are smokers. Among 50 controls, 20 are smokers. The Odds Ratio for oral cancer associated with smoking is:

• A 2
• B 4
• C 8
• D 6 ✓

Explanation

Odds of exposure in cases = 40/10 = 4; Odds of exposure in controls = 20/30 = 0.667. OR = 4/0.667 = 6. Alternatively, using the cross-product formula: OR = (40×30)/(20×10) = 1200/200 = 6. An OR of 6 means smokers have 6 times the odds of developing oral cancer compared to non-smokers.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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