Alcohol consumption, smoking, and other risk factors and prostate cancer in a large health plan cohort in California (United States).

Alcohol consumption and cigarette smoking have been suggested as possible causes of prostate cancer. We therefore examined this relation in a cohort of 43,432 men who were members of a prepaid health plan in northern California (United States) and who had received a health examination in the period from 1979 through 1985. Detailed information on demographic variables, alcohol consumption, smoking habits, medical complaints and conditions, occupation, and surgery (including vasectomy) was assessed. Symptoms of prostatism and a history of sexually transmitted diseases were abstracted from the medical records of all prostate cancer patients and of a matched subsample of randomly selected control-subjects. Alcohol consumption was associated with no elevated prostate cancer risk for the 238 men in our study in whom prostate cancer developed, but smoking one or more packs of cigarettes per day was associated with an adjusted relative risk (RR) of 1.9 (95 percent confidence interval [CI] = 1.2-3.1). Prostate cancer risk for Black men was 2.2 (CI = 1.6-3.1) when compared with that for White men, and education level was associated positively in an increasing trend (P < 0.020) up to an RR of 1.4 (CI = 0.9-2.1) among men with postgraduate education. Symptoms of prostate hypertrophy were not associated with elevated risk of prostate cancer if they occurred two or more years before the diagnosis. The finding that smoking increased the risk of prostate cancer confirms the observations of others but needs cautious interpretation because we were unable to adjust for the potential confounding effect of dietary and hormonal factors.