A cohort study of farming and risk of prostate cancer in Iowa

Although farming has been linked to prostate cancer mortality, few investig ations have addressed its association with prostate cancer incidence. We fo llowed a population-based cohort of 1,177 cancer free men for up to 9 years and identified 81 incident prostate cancers. Men whose usual occupation wa s farmer were at an increased risk of prostate cancer after adjust ment for age, smoking, alcohol, and dietary factors (RR = 1.7; 95% CI 1.0-2.7). Exc lusion of well differentiated, localized tumors slightly strengthened the a ssociation (RR = 2.0; 95% CI = 1.1-3.6). Risk was confined to older (age 70 + years) farmers (RR = 2.2; 95% CI = 1.1-4.3); we found no evidence of an e ffect among younger farmers (RR = 1.0; 95% CI = 0.4-2.1).