Risk factors for colorectal cancer in a prospective study among U.S. white men.

The association of diet, smoking/drinking and occupation with subsequent risk of fatal colorectal cancer was investigated in a cohort of 17,633 white males aged 35 and older, who completed a mail questionnaire in 1966. During the subsequent 20 years of follow-up, 120 colon cancer and 25 rectal cancer deaths were identified. Due to small numbers, no significant dose-response trends were observed in the study, but risk of colon cancer was elevated among heavy cigarette smokers (> or = 30/day; RR = 2.3, 95% CI 0.9-5.7), heavy beer drinkers (> or = 14 times/month; RR = 1.9, 95% CI 1.0-3.8) and white-collar workers (RR = 1.7, 95% CI 1.0-3.0) or crafts workers within service and trade industries (RR = 2.6, 95% CI 1.1-5.8). In addition, an increased risk was seen for those who consumed red meat more than twice a day (RR = 1.8, 95% CI 0.8-4.4). Risk patterns for cancers of the colon and rectum combined were similar to those reported for cancer of the colon, but the estimates were somewhat dampened. Our findings support previous reports that a high intake of red meat and a sedentary life-style may increase the risk of colon cancer.