Family history and the risk of prostate cancer

Objectives. Several studies have identified prostate cancer family history as a risk factor for prostate cancer incidence, typically associated with a twofold to fourfold increase in risk. A family history of breast cancer ha s also been implicated. We investigated the associations between prostate c ancer incidence and family histories of prostate and breast cancer, control ling for possible confounding due to environmental factors. Methods. Data from the random sample-based Massachusetts Male Aging Study c ohort (1987 to 1997) were used. Incidence rates were calculated as the numb er of cases per person-year of follow-up. Covariates were adjusted for usin g Poisson regression. Results. Among 1149 men with an average of 8.7 person-years of follow-up, 5 7 were diagnosed with prostate cancer, 110 men reported a prostate cancer f amily history, and 157 reported a breast cancer family history. The age-adj usted relative risk (RR) of prostate cancer incidence associated with prost ate cancer family history was 3.29 (95% confidence interval [CI] 1.82 to 5. 94]. No evidence of heterogeneity was found across age levels (P = 0.83). A dditional adjusting for environmental factors such as smoking, alcohol use, body mass index, physical activity, education, sexually transmitted diseas e history, diet, and hormone levels yielded a slightly higher RR (3.78, 95% CI 1.96 to 7.28). No association with a family history of breast cancer wa s evident (RR = 1.18, 95% CI 0.51 to 2.43). Conclusions. We found an association between prostate cancer incidence and a family history of prostate cancer, independent of environmental factors. No association with a family history of breast cancer was evident. UROLOGY 56: 803-806, 2000. (C) 2000, Elsevier Science Inc.