Light Drinking May Relate to an Increased Risk for Certain Cancers

The majority of observational studies have shown that alcohol intake, especially heavy drinking, increases a number of upper aerodigestive tract and other cancers, and even lower risk drinking is associated with an increase in the risk of breast cancer. This meta-analysis of 222 articles compared the effects of “light” drinking (an average reported intake of ≤1 drinks per typical drinking day) versus “nondrinking” in terms of relative risks for a number of cancers. The analysis included roughly 92,000 light drinkers and 60,000 nondrinkers.

• The authors found small but significant increases in risk from light drinking for cancers of the oral cavity and pharynx (relative risk [RR], 1.17), esophageal squamous cell carcinoma (RR, 1.30), and breast cancer in women (RR, 1.05).

• No increased risk from light drinking was found for cancers of the colorectum, liver, or larynx.

Comments:

Although the increases in cancer risk found in this study were small, they could lead to large numbers of cancer cases, since most drinkers are “light” consumers. The statistical methodology was correct and done appropriately; however, there are methodological limitations.  For example, both ex-drinkers and never-drinkers were included in the reference group, and estimates of effect were not adjusted based on other lifestyle habits, including smoking. The authors also did not address the net health effects of light drinking. Since alcohol is a known carcinogen, the results remain plausible, but additional studies with fewer limitations are needed to better delineate the potential risks of “light” drinking.

R. Curtis Ellison, MD

Reference:

Bagnardi V, Rota M, Botteri E, et al. Light alcohol drinking and cancer: a meta-analysis. Ann Oncol. August 21, 2012 [Epub ahead of print]. doi:10.1093/annonc/mds337