Coffee, tea, tobacco, and cancer of the large bowel.

The impact of tobacco use and coffee and tea intake on the risk of colorectal cancer is unclear. Previous research has suggested that coffee may be protective against these cancers, and investigation regarding tea or cigarette smoking has yielded inconsistent results. To clarify these issues, we evaluated coffee and tea intake and tobacco smoking as risk factors for cancer of the colon and rectum in a population-based case-control study from Stockholm, Sweden. Cases were ascertained from the regional cancer registry, and controls identified through population registers. Subjects completed a questionnaire requesting information regarding foods and beverages consumed, exercise, tobacco use, and personal characteristics. Logistic regression modelling was used to compute odds ratios. A total of 352 cases of colon cancer, 217 cases of rectal cancer, and 512 controls took part. High coffee intake was negatively associated with the risk of colon cancer: the odds ratio for those drinking 6 or more cups per day was 0.55 (95% confidence interval, 0.31-0.96) compared to those drinking one or fewer. There was no association with rectal cancer. For tea, the associations were the opposite: there was no association with colon cancer risk, but the odds ratio for rectal cancer was 0.56 (95% confidence interval, 0.34-0.90) for those drinking 2 or more cups per day compared with those drinking none. Smokers of 11 or more cigarettes per day had a 20 to 30% reduction in the risk of colon and rectal cancer, but these findings were consistent with chance. There was no association of long-term cigarette smoking with risk.