Association of Alcohol Consumption and the Risk of Cancer

With questionnaire data from 124,193 Kaiser Permanente patients (comprising 17.8 years of follow-up and 18,637 cases of cancer), investigators related reported baseline alcohol intake to the risk of 15 types of cancer. They used persistent abstainers as the referent group, with average alcohol consumption categories of < 1 drink in a day defined as “light,” 1–2 drinks in a day as “moderate,” and ≥ 3 or drinks in day as “heavy.” Under-reporting of alcohol consumption was assessed as “likely” if data from the study indicated use might be higher (e.g., heavy intake on other occasions, evidence of unhealthy alcohol use, alcohol-related liver disease). It was assessed as “unlikely” if no such information was present in the overall study data.

• People with heavy consumption had significant increases in risk of cancers at many sites, especially upper aero-digestive tract (hazard ratio [HR], 2.5), melanoma (HR, 2.2), colo-rectal (HR, 1.4), lung (HR, 1.3), breast (HR, 1.3), and prostate (HR, 1.1). 
• Even people with “light” consumption had slightly increased risk of cancers of the breast (HR, 1.1) and colo-rectum (HR, 1.1), and especially melanoma (HR, 1.6), with the last possibly confounded by sun exposure.
• Among participants reporting “moderate” intake, those considered to be “likely under-reporters” had higher overall risk of all cancer (HR, 1.4) than those considered unlikely to be under-reporting their intake (HR 1.1). No significant differences were found according to type of alcoholic beverage.  

Comments:

This well-done large prospective cohort study confirms increased risk for a number of types of cancer from alcohol consumption, with slight increases for melanoma and breast and colo-rectal cancer, even among people with “light” consumption. It points out the importance of under-reporting of alcohol consumption among people with “moderate” use on the risk of cancer. When considering alcohol use, an increase in risk of some cancers even for people with “light” to “moderate” use should enter into the risk-benefit equation, especially for young persons. After the age of 50, the reduced risk of cardiovascular disease and in total mortality in observational studies associated with “light” to “moderate” drinking may outweigh the possible cancer risks.

R. Curtis Ellison, MD

Reference:

Klatsky AL, Li Y, Nicole Tran H, et al. Alcohol intake, beverage choice, and cancer: a cohort study in a large Kaiser Permanente population. Perm J. 2015; 19(2):28–34.