Tea consumption and the risk of colorectal cancer in Sweden

The association between tea drinking and colorectal cancer risk remains unc lear. The evidence for black tea is sparse but may indicate an increased ri sk with regular use. Because black tea is a common beverage in many populat ions, the significant twofold increased risk of colon cancer recently repor ted from a large prospective cohort of male Finnish smokers is disconcertin g. Using Cox proportional hazards models to estimate relative risks, we exa mined this association in a large, population-based prospective cohort stud y in Sweden. During an average 9.6 years of follow-up of our cohort of 61,4 63 women (588,270 person yr), we observed 460 incident cases of colorectal cancer (291 colon, 159 rectal, and 10 with both colon and rectal cancer). W e observed no association between tea consumption and combined colorectal c ancers in age- or multivariate-adjusted models. With the use of collapsed e xposure categories, the multivariate-adjusted relative risk for the highest exposure (greater than or equal to2 cups/day) compared with the lowest (ne ver or seldom) was 0.97 (95% confidence interval = 0.63-1.48, p for trend = 0.34). Examining the association by cancer subsite, we observed no associa tion between tea consumption and proximal, distal, or combined colon cancer s. We did, however, observe a nonsignificant positive association with rect al cancers, which became stronger and statistically significant among women greater than or equal to 65 years of age at baseline. Our data do not supp ort the strong, dose-dependent positive association with colon cancer found in the Finnish study.