In a cohort study of smoking and myocardial infarction in City A,the number of myocardial infarctions were 250 cases among 7,000 smokers and the number of myocardial infarctions were 150 cases among 20,000 nonsmokers.What is the attributable risk (risk difference) of smoking?

A) 2.8 per 1,000
B) 3.6 per 1,000
C) 7.5 per 1,000
D) 28.2 per 1,000
E) 35.7 per 1,000

Attributable Risk

The difference in the rate of a condition between an exposed population and an unexposed population, which can be attributed to the exposure.

Cohort Study

An observational study design that follows a group of people over time to investigate the causes of disease and establish links between risk factors and health outcomes.

Myocardial Infarction

A medical condition commonly known as a heart attack, which occurs when blood flow to the heart is blocked, causing heart muscle damage.