Does Alcohol Increase Your Risk of Cancer?

Recent news reports have raised concerns that drinking alcohol increases the risk for melanoma, a deadly form of skin cancer. Alcohol is a significant risk factor for cancer, but the headlines are a bit misleading.

What the research really says about alcohol and cancer risk

The study in question reports that people who drink alcohol regularly had a 20 percent higher risk of developing malignant (spreading) melanoma than people who drink occasionally or not at all. The research is based on a review of multiple studies.

According to Cancer Research, UK, however, these results are only significant when you include lower quality studies. In other words if you exclude the lower quality studies, the results are no longer statistically significant. Furthermore, a link between the two does not necessarily imply cause, as the headlines purport. There may be other factors contributing to the association that are not part of the study.

These sensationalized headlines gloss over the seriousness of alcohol as a significant risk factor for many types of cancers, including oral cancers and cancers of the esophagus, liver, breast, colon, and rectum. According to the National Cancer Institute, the more alcohol a person drinks, particularly over time, the higher the person's risk of developing an alcohol-associated cancer.

A study in the April 2013 issue of the American Journal of Public Health reported that cancer risks are greatest, and alcohol-attributable cancer deaths are more common, among individuals who drink three or more alcoholic drinks per day (40 grams). However, approximately 30 percent of alcohol-attributable cancer deaths are in people who consumed 20 grams per day or less. In fact, about 15 percent of breast cancer deaths among women in the U.S. are attributable to alcohol consumption.

Approximately 19,500 Americans died from alcohol-attributable cancers in 2009, 3.5 percent of all cancer deaths.

But what about alcohol's heart-healthy reputation? The researchers write, "When viewed in the broad context, alcohol results in 10 times as many deaths worldwide even after one considers possible beneficial effects of low-level use for cardiovascular disease and diabetes."

How alcohol contributes to cancer risk

While the full picture of how alcohol influences the development of cancer is still uncertain, the National Cancer Institute (NCI) suggests several possible mechanisms. Our body breaks down alcohol into acetaldehyde, a toxic chemical and probable human carcinogen, and generates chemically reactive molecules containing oxygen (oxidation). These actions can damage DNA and proteins. Alcohol also impairs the body's ability to break down and absorb nutrients and increases blood levels of estrogen, raising the risk for breast cancer.

Limiting your alcohol drinking to one drink per day for women and two for men is an important cancer risk-reduction strategy.

Rajiv Datta, MD, reviewed this article.



Sources:


Amy E. Millen, Margaret A. Tucker, Patricia Hartge, Allan Halpern, David E. Elder, DuPont Guerry IV, Elizabeth A. Holly, Richard W. Sagebiel, and Nancy Potischman, "Diet and Melanoma in a Case-Control Study, Cancer Epidemiology Biomarkers & Prevention 13 (2004): 1042. http://cebp.aacrjournals.org/content/13/6/1042.long

Sarah Williams, "Why today's reports about skin cancer and alcohol are misleading," Cancer Research UK, January 29, 2014, accessed February 13, 2014. http://scienceblog.cancerresearchuk.org/2014/01/29/why-todays-reports-about-skin-cancer-and-alcohol-are-misleading/

Carolyn Newbergh, "Drinking Causes 3.5% of Cancer Deaths - More Than from Melanoma, New Study Finds," Public Health Institute, February 14, 2013. http://www.phi.org/news-events/411/drinking-causes-35-of-cancer-deaths-more-than-from-melanoma-new-study-finds

David E. Nelson, MD, MPH, Dwayne W. Jarman, DVM, MPH, Jürgen Rehm, PhD, Thomas K. Greenfield, PhD, Grégoire Rey, PhD, William C. Kerr, PhD, Paige Miller, PhD, MPH, Kevin D. Shield, MHSc, Yu Ye, MA, and Timothy S. Naimi, MD, MPH, "Alcohol-Attributable Cancer Deaths and Years of Potential Life Lost in the United States," American Journal of Public Health 103(4) 2013, doi/full/10.2105/AJPH.2012.301199. http://ajph.aphapublications.org/doi/pdf/10.2105/AJPH.2012.301199

Alcohol and Cancer Risk," National Cancer Institute, June 24, 2013, accessed February 11, 2014. http://www.cancer.gov/cancertopics/factsheet/Risk/alcohol