A meta-analysis of alcoholic beverage consumption in relation to risk of colorectal cancer.

Quantitative methods were used to review epidemiologic data relating consumption of alcoholic beverages to risk of colorectal cancer. The data (27 studies) supported the presence of a weak association. For consumption of two alcoholic beverages daily, on average the relative risk of colorectal cancer was 1.10 (95% confidence interval 1.05-1.14). Other findings were: (1) the association did not vary according to gender or site within the large bowel; (2) results from follow-up studies (relative risk 1.32, 95% confidence interval 1.16-1.51) suggested a stronger relationship than those from case-control studies (relative risk 1.07, 95% confidence interval 1.02-1.12); and (3) the evidence supporting beverage specificity was not conclusive, although the results were consistent with a stronger association with consumption of beer (relative risk 1.26, 95% confidence interval 1.13-1.41) than with consumption of wine (relative risk 1.11, 95% confidence interval 0.91-1.36) or liquor (relative risk 1.13, 95% confidence interval 0.99-1.29). Because the magnitude of the association between alcohol consumption and risk of colorectal cancer was small, the findings regarding a causal role of alcohol were inconclusive.