Coffee consumption and risk of colorectal cancer: a dose-response analysis of observational studies.

Coffee consumption has been linked to risk of colorectal cancer theoretically, but the findings were conflicting from observational studies. Results from the recent meta-analysis suggested a moderate favorable effect of coffee consumption on colorectal cancer risk, especially for colon cancer. However, the relationship, if exists, between coffee consumption and colorectal cancer risk is unclear. Thus, the dose-response relationship was assessed by restricted cubic spline model and multivariate random-effect meta-regression. The results suggested that a significant association was found between coffee consumption and decreased risk of colorectal and colon cancer among subjects consuming ≥4 cups of coffee per day. A potential nonlinear relationship should be assessed before assuming a linear relationship.