Among uranium mine workers, 150 lung cancer deaths are observed over 20 years, whereas 100 deaths were expected based on age-specific mortality rates of the national male population. The Standardized Mortality Ratio (SMR) is:

• A 0.67, indicating lower mortality than expected
• B 2.5, indicating mortality 2.5 times the national rate
• C 150%, indicating 150 additional deaths above expectation
• D 1.5, indicating a 50% excess of lung cancer deaths ✓

Explanation

SMR is calculated as observed deaths divided by expected deaths, here 150 divided by 100, giving 1.5 or 150%. An SMR of 1.5 means the cohort experienced 50% more lung cancer deaths than the standard population after adjustment for age structure. Option C confuses the ratio with absolute excess deaths, which is 50. Option B mistakenly divides expected by some other figure. Option A inverts the ratio by calculating expected over observed.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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