Does “Light” Drinking Increase the Risk of Cancer?

There are a number of types of cancer for which risk is clearly increased among people with heavy drinking. Researchers conducted a meta-analysis of data from 60 high-quality cohort studies to identify an association between lower-risk alcohol consumption and the risk of cancer incidence and mortality.

• “Very light” consumption (≤0.5 standard drink/day) was associated with an increased incidence of female breast cancer (relative ratio [RR], 1.04), but also with a decreased risk of mortality from female breast cancer (RR, 0.79). It was also associated with a decreased incidence of lung cancer (RR, 0.89).
• “Light” consumption (≤1 drink/day) was associated with an increased incidence of female breast cancer (RR, 1.09), female and male colorectal cancer (RR, 1.04), and female and male malignant melanoma (RR, 1.44). It was also associated with a decreased incidence of lung cancer (RR, 0.91).
• “Moderate” consumption (1–2 drinks/day) was associated with an increased incidence of male colorectal cancer and female breast cancer, whereas it was also associated with a decreased incidence of both female and male hematologic malignancy. It was associated with an increased risk of mortality from female colorectal cancer (RR, 2.51, based on 1 study) and female breast cancer (RR, 1.04, based on 2 studies), but with a reduced risk of mortality from male kidney cancer (RR, 0.46). It was not associated with mortality for other cancers.

Comments: This well-done analysis supports most previous epidemiologic evidence on the association between “light” to “moderate” alcohol consumption and cancer. The main weaknesses of the study related to the lack of evaluation of a number of known confounders. Further, the authors did not describe the effects of alcohol consumption on total mortality. Thus, it remains difficult for scientists to use this study to provide scientifically sound guidelines regarding the health consequences of alcohol consumption.

R. Curtis Ellison, MD

Reference: Choi YJ, Myung SK, Lee JH. Light alcohol drinking and risk of cancer: a meta-analysis of cohort studies. Cancer Res Treat. 2017 [Epub ahead of print]. doi: 10.4143/crt.2017.094.