Tea consumption and cancer risk.

The relationship between tea consumption and cancer risk has been analyzed using data from an integrated series of case-control studies conducted in northern Italy between 1983 and 1990. The dataset included 119 histologically confirmed cancers of the oral cavity and pharynx, 294 of the esophagus, 564 of the stomach, 673 of the colon, 406 of the rectum, 258 of the liver, 41 of the gallbladder, 303 of the pancreas, 149 of the larynx, 2,860 of the breast, 567 of the endometrium, 742 of the ovary, 107 of the prostate, 365 of the bladder, 147 of the kidney, 120 of the thyroid, and a total of 6,147 controls admitted to hospital for acute nonneoplastic conditions unrelated to long-term dietary modifications. Multivariate relative risks (RR) for tea consumption were derived after allowance for age, sex, area of residence, education, smoking, and coffee consumption. All the estimates for tea consumption were close to unity, the highest values being 1.4 for rectum, gallbladder, and endometrium. There was no association with cancers of the oral cavity (RR = 0.6), esophagus (RR = 1.0), stomach (RR = 1.0), bladder (RR = 0.8), kidney (RR = 1.1), prostate (RR = 0.9), or any other site considered. Although in northern Italy tea was consumed daily by only a limited proportion of the population, this integrated series of studies offers further reassuring evidence on the relationship between tea and cancer risk.