Question

It is known that smoking is also a risk factor for lung cancer and other diseases. Studies have shown that the death rate per 100,000 for lung cancer is 7 among non-smokers and 71 among smokers. The death rate per 100,000 for coronary thrombosis is 422 among non-smokers and 599 among smokers. The prevalence of smoking in the population is 55%.

What is the attributable risk of dying of lung cancer for smokers versus non-smokers?

What is the interpretation of the attributable risk?

Answer 1

Here incidence in exposed means who have smoking and died due to lung cancer = 71

Incidence in nonexposed means who never have smoking and died in lung cancer = 7

ATTRIBUTABLE RISK =[ (incidence in exposed- incidence in nonexposed )/ incidence among exposed] × 100 = [(71-7)/71] ×100 = (64/71)× 100 = 0.90 ×100 = 90%

Aattributable risk is expressed in percentage.

Easily it can be defined as dthe percentage or share attributed by a exposure or risk factor( here in this case smoking) causes the disease or death( here in this case dying due to lung cancer).

INTERPRETATION:- Attributable risk is 90% means the persons who have smoking are 90% more chance in developing lung cancer with respect to the non smoker. In other way it can be explained, that if the smoking is avoided the occurrence of lung cancer reduce by 90%.