Question

The incidence of heart attacks among smokers in a community is 30.0 per 100,000 per year. The incidence of heart attacks among nonsmokers in this community is 4.0 per 100,000 per year. The proportion of nonsmokers in this community is 75%.

What proportion of the risk of heart attacks among smokers can be attributed to smoking?

(Select one) a. 6.5% b. 26.0% c. 76.0% d. 86.7%

What proportion of the risk of heart attacks in the total population can be attributed to smoking?

(Select one) a. 21.3% b. 61.9% c. 82.2% d. Cannot be calculated given the information provided.

Answer 1

The proportion of the risk of heart attacks among smokers that can be attributed to smoking is 86.7%. The proportion of the risk of heart attacks in the total population that can be attributed to smoking is 19.12%.

Step-by-step explanation:

To find the proportion of the risk of heart attacks among smokers that can be attributed to smoking, we need to calculate the risk difference between smokers and nonsmokers. The risk difference is calculated by subtracting the incidence rate of heart attacks among nonsmokers from the incidence rate among smokers. In this case, the risk difference is 30.0 - 4.0 = 26.0 per 100,000 per year.

To determine the proportion, we divide the risk difference by the incidence rate among smokers. Proportion = (Risk Difference / Incidence Rate among Smokers) * 100%. Proportion = (26.0 / 30.0) * 100% = 86.7%.

To find the proportion of the risk of heart attacks in the total population that can be attributed to smoking, we need to calculate the weighted risk difference. The weighted risk difference takes into account the proportion of smokers and nonsmokers in the community. In this case, the proportion of smokers is 1 - 0.75 = 0.25 and the proportion of nonsmokers is 0.75.

Weighted Risk Difference = (Proportion of Smokers * Risk Difference) + (Proportion of Nonsmokers * Risk Difference) = (0.25 * 26.0) + (0.75 * 0) = 6.5 per 100,000 per year.