In 1990 there were 4500 deaths due to lung diseases in miner

In 1990, there were 4,500 deaths due to lung diseases in miners aged 20 to 64 years. The expected number of deaths in this occupational group, based on age-specific deaths rates from lung diseases in all males aged 20 to 64 years, was 1,800 during 1990. What is the standardized mortality ratio (SMR) for lung disease in miners? Interpret this ratio.

Solution

Standardized Mortality Ratio (SMR) is a ratio between the observed number of deaths in an study population and the number of deaths would be expected

SMR = 4500 / 1800 = 2.5

intepretation

An SMR for bladder cancer of 1.70 in the exposed group would mean that there is 70% more cases of death due to bladder cancer in the cohort than in the reference population

so for our case

SMR = 2.5

the increase is more than double so it will actually be 2.5 %