Coffee intake and the risk of colorectal adenoma: The colorectal adenoma study in Tokyo.

Coffee is a commonly consumed beverage which contains several potential anticarcinogenic and chemopreventive compounds, and has been hypothesized to have protective effects in colorectal neoplasia. However, the limited available data on coffee consumption in relation to colorectal adenoma (CRA), a precursor lesion to most colorectal cancers, remain largely inconsistent. In this study, we evaluated the association of coffee intake with the risk of CRA in a middle-aged Japanese population. Study subjects were selected from examinees who underwent total colonoscopy as part of a cancer screening program and responded to self-administered dietary and lifestyle questionnaires. A total of 738 patients with adenoma and 697 controls were included in the study. Coffee intake was assessed with a food frequency questionnaire, and divided into quartiles based on the distribution among controls. Unconditional logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI) of CRA, with adjustment for potential confounding factors. High coffee consumption was associated with a reduced risk of CRA, with a multivariate-adjusted OR for the highest versus lowest quartile of coffee intake of 0.67 (95% CI = 0.48-0.93; ptrend  = 0.02). The inverse association of coffee intake was limited to proximal (OR = 0.64; 95%CI = 0.44-0.95; ptrend  = 0.04) and distal colon adenoma (OR = 0.62; 95%CI = 0.39-0.99; ptrend  = 0.06), and appeared to be more evident with small (OR = 0.68; 95%CI = 0.49-0.96; ptrend  = 0.04) and single adenomas (OR = 0.65; 95%CI = 0.44-0.95; ptrend  = 0.02). Green tea intake was not found to be associated with CRA risk. This study provides support for the protective effect of coffee drinking on colon adenomas, a precursor of colon cancer.