A cohort study was conducted to assess the relationship between high saturated fat consumption and the occurrence of colorectal carcinoma among women. A group of women aged 40-65 was selected. The baseline saturated fat consumption was calculated using a food questionnaire, and the cohort was followed for seven years for the development of colon cancer. The study showed that women with high baseline saturated fat consumption have four times the risk of colorectal cancer in a 7-year period, compared to women with low fat consumption (RR = 4.0, 95% CI = 1.5 - 6.5). According to the study results, what percent of colorectal carcinoma in women with high fat consumption could be attributed to their diet?

Question

A cohort study was conducted to assess the relationship between high saturated fat consumption and the occurrence of colorectal carcinoma among women.  A group of women aged 40-65 was selected.  The baseline saturated fat consumption was calculated using a food questionnaire, and the cohort was followed for seven years for the development of colon cancer.  The study showed that women with high baseline saturated fat consumption have four times the risk of colorectal cancer in a 7-year period, compared to women with low fat consumption (RR = 4.0, 95% CI = 1.5 - 6.5).  According to the study results, what percent of colorectal carcinoma in women with high fat consumption could be attributed to their diet?

Quizplus · Accepted Answer

Attributable risk percent (ARP) or etiologic fraction is an important measure of the impact of a risk factor being studied. ARP represents the excess risk in a population that can be explained by exposure to a particular risk factor. It is calculated by subtracting the risk in the unexposed population (baseline risk) from the risk in the exposed population, and dividing the result by the risk in the exposed population: ARP = (risk in exposed - risk in unexposed)/risk in exposed. An easier way to calculate the ARP is to derive it from the relative risk (RR): ARP = (RR - 1)/RR. In this case, ARP = (4.0 - 1)/4.0 = 0.75 (75%). According to the study results, 75% of colorectal carcinoma in the high consumption group was attributable to high saturated fat intake. Educational Objective: ARP represents the excess risk in the exposed population that can be attributed to the risk factor. It can be easily derived from the relative risk using the following formula: ARP = (RR - 1)/RR.

A Cohort Study Was Conducted to Assess the Relationship Between