Coffee and tea intake and risk of cancers of the colon and rectum: a study of 3,530 cases and 7,057 controls.

The relationship between coffee, decaffeinated coffee and tea intake and risk of cancers of the colon and rectum was considered combining data from 2 case-control studies, one conducted between 1985 and 1991 in Northern Italy and the other between 1991 and 1996 in 6 Italian centers. Cases were patients below age 80, with histologically confirmed cancer of the colon (n = 2,166) or rectum (n = 1,364), and controls were 7,057 patients admitted to hospital for a wide spectrum of acute, non-neoplastic, non-digestive tract diseases. Compared with coffee non-drinkers, the risk of colon cancer was reduced in drinkers of 4 or more cups/day [multivariate odds ratios (ORs) 0.73; 95% confidence intervals 0.60-0.89), with a significant trend in risk with dose; no significant association emerged between coffee drinking and risk of rectal cancer (OR 1.00 for drinkers of 4 or more cups/day). Decaffeinated coffee was consumed in small amounts by about 4% of cases and controls and the OR was 0.92 for colon and 0.88 for rectal cancers. Tea consumption was generally limited to 1 cup/day or to occasional intake and did not substantially modify the risk of colon and rectal cancers. No significant heterogeneity was found for the inverse relationship between coffee intake and colon cancer risk across strata of age at diagnosis, sex, smoking status, total alcohol and meat and vegetable intake, while the protection of coffee was stronger in people eating 3 or more meals/day. Thus, our results confirm that coffee intake has a quantifiable protective effect on colon cancer risk.