Lifestyle and anthropometric risk factors for prostate cancer in a cohort of Iowa men

PURPOSE: Several lines of evidence suggest that prostate cancer has a hormo nal etiology. We evaluated factors known to modulate the endocrine system, including alcohol and tobacco use, physical activity, and obesity as risk f actors for prostate cancer. METHODS: Cancer-free controls (n = 1572) who participated in a population-b ased case control study from 1986-1989 (81% response rate) were followed th rough 1995 for cancer incidence by linkage to the Iowa Cancer Registry; 101 incident prostate cancers were identified. RESULTS: Compared with non-users of alcohol, men who consumed <22 grams alc ohol per week (relative risk [RR] = 1.1; 95% Confidence Interval [CI] 0.6-2 .1), 22-96 grams alcohol per week (RR = 2.6; 95% CI 1.4-4.6) and >96 grams alcohol per week (RR = 3.1; 95% CI 1.5-6.3) were at increased risk of prost ate cancer after adjustment: for age, family history of prostate cancer, bo dy mass index, total energy, and intake of carbohydrate, linoleic acid, lyc opene, retinol, and red meat (p for trend < 0.0001). The respective RRs wer e similar when assessing type of alcohol consumed (beer, wine or liquor) or when well-differentiated, localized tumors were excluded. Body mass index was only weakly and positively associated with prostate cancer after adjust ment for age (p for trend = 0.3), but this association strengthened after m ultivariate adjustment (p for trend = 0.08) and exclusion of well-different iated, localized tumors (p for trend = 0.03). For the latter tumors, men wi th a BMI of 24.1-26.6 kg/m(2) (RR = 1.5; 95% CI 0.7 - 3.0) and >26.6 kg/m(2 ) (RR = 2.1; 95% CI 1.1-4.3) were at elevated risk compared to men with a B MI <24.1 kg/m(2). Tobacco use (cigarettes, cigar/pipe, chewing tobacco and snuff use), height, weight, and both leisure and occupational physical acti vity were not associated with risk of prostate cancer in this cohort. CONCLUSIONS: These data suggest that in white men obesity is a risk factor for more clinically significant prostate cancer and confirm limited previou s reports showing that alcohol consumption is positively associated with pr ostate cancer and that this risk is not limited to any specific type of alc ohol. Ann Epidemiol 2000;10:361-369. Published by Elsevier Science Inc.