Light To Moderate Drinking Increases Cancer Risk in Women

Dr. Yin Cao MPH, ScD Postdoctoral Fellow, Department of Nutrition Harvard T. H. Chan School of Public Interview with:
Dr. Yin Cao MPH, ScD
Postdoctoral Fellow, Department of Nutrition
Harvard T. H. Chan School of Public Health

Medical Research: What is the background for this study? What are the main findings?

Dr. Cao: Light-to-moderate drinking, defined as up to 1 drink (roughly corresponds to a 355ml bottle of beer, or a small [118-148 ml] glass of wine or 44ml of liquor) for women and up to 2 drinks for men, is prevalent in many western countries. It is believed that light-to-moderate drinking may be healthy for the heart. However, the influence of light-to-moderate drinking on risk of overall cancer is less clear, although it is well known that heavy alcohol intake increases risk of several cancers, including cancers of colorectum, female breast, oral cavity, pharynx, larynx, liver, and esophagus.

Also because drinkers are more likely to be smokers, and smoking is the major risk factor for all of the alcohol-related cancers (mentioned above) except breast cancer, it is thus difficult to tease out the influence of alcohol on cancer in studies among a mixed population of ever and never smokers. In particular, it is important to know how light and moderate drinking would affect cancer risk particularly among never smokers, who now make up the majority of the population in many western countries.

Our main findings are that, light-to-moderate drinking minimally increases risk of overall cancerFor men, the association with alcohol related cancers was primarily observed among smokers, and light to moderate drinking did not appreciably increase risk in never smokers. Among women, even consumption of up to one drink per day was associated with increased risk of alcohol-related cancers (mainly breast cancer) for both never and ever smokers.

Medical Research: What should clinicians and patients take away from your report?

Dr. Cao: Overall, our study reinforces the dietary guidelines that it is important not to go beyond 1 drink per day for women and 2 drinks per day for men. For women, the potential modest elevated risk of alcohol-related cancers, primary breast cancer, should also weigh against potential benefits on cardiovascular diseases. Men who ever smoked should limit alcohol intake to below recommended limit. Decisions on levels of alcohol consumption should also take into account history of smoking, family history of alcohol-related cancers, and risk profile for cardiovascular diseases. Smoking and heavy alcohol consumption should both be avoided to prevent cancer.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Cao: It remains important to define the optimal drinking level for people who drink, taking into account personal risk profile (e.g. smoking history and family history), and risks and benefits associated with major chronic diseases (e.g. overall cancer, alcohol-related cancers, cardiovascular diseases, etc.). It is also important to identify the timing to get risks/benefits if any (e.g. how many years of drinking are needed). More research is also needed to explore the mechanisms by which light-to-moderate drinking influences breast cancer risk, and identify subgroup of women who are more susceptible to breast cancer risk associated with light and moderate alcohol intake.


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Dr. Yin Cao MD PhD (2015). Light To Moderate Drinking Increases Cancer Risk in Women 

Last Updated on August 19, 2015 by Marie Benz MD FAAD