Coffee contains many bioactive substances that can play a role on colorectal cancer. Epidemiological evidence of coffee intake and colorectal cancer is, however, inconsistent.
To provide further information on the risk of colorectal cancer in relation to coffee consumption.
Data derive from two companion case-control studies conducted in Italy and Spain within the European Union Project on Health Impacts of long-term exposure to disinfection by-products in Drinking Water and the Spanish Multi-Case Control study on Cancer. These included a total of 2289 incident cases with colorectal cancer and 3995 controls with information on coffee intake. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were derived from unconditional logistic regression models, adjusted for study centre, sex, age, education, smoking, and other covariates.
Compared with never coffee drinkers, the OR was 0.99 (95% CI 0.95–1.02) for total coffee consumption. There was no significant trend in risk with dose or duration, the ORs being 0.95 (95% CI 0.72–1.25) for an amount of five or more cups per day of coffee and 0.95 (95% CI 0.75–1.19) for a duration of consumption of 50 years or longer. The OR was 1.04 (95% CI 0.87–1.25) for two or more cups per day of decaffeinated coffee. There were no heterogeneity across strata of various covariates, as well as no apparent differences between various anatomical subsites.
This large pooled analysis of two studies shows no association of coffee and decaffeinated coffee with colorectal cancer risk.