Among miners exposed to radon, 40 deaths from lung cancer are observed over a defined period. Using national age-specific lung cancer mortality rates applied to the same age distribution of these miners, 25 deaths would have been expected. What is the Standardized Mortality Ratio?
- A 0.63
- B 1.60 ✓
- C 65%
- D 160 deaths per 1000 population
Correct answer: B. 1.60
Explanation
SMR is calculated by indirect standardization as observed deaths divided by expected deaths, expressed as a ratio or percentage. Here 40 divided by 25 gives 1.60, or 160%. An SMR above 100% indicates excess mortality compared with the standard population. Option A results from inverting the ratio, and option C confuses the SMR with a proportionate measure. Indirect standardization requires only the total observed and expected counts.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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