The newest report from the World Cancer Research Fund and the American Institute for Cancer Research concludes that one glass of alcohol per day can increase the risk of breast cancer1. Let’s bring insights and perspective.
Alcohol consumption can increase the risk of both premenopausal and postmenopausal breast cancer, although the association with postmenopausal breast cancer is stronger. The report states that consumption of alcohol is a probable cause of premenopausal breast cancer, which was downgraded from convincing since the last report in 2010. Among premenopausal women, breast cancer risk increases by 5% for every 10 g of alcohol consumed per day (9% risk in 2010 report). For postmenopausal women, consumption of alcohol is a convincing cause of breast cancer and the risk increases by 9% for every 10 g of alcohol consumed (8% risk in 2010 report).
When looking at specific beverages, for premenopausal women especially beer increases the risk. Among postmenopausal women the risk is highest with wine consumption.
The researchers indicate that the mechanism behind the association between alcohol and breast cancer still remain uncertain and are likely complex. Different mechanisms are likely involved in different types of breast cancer. These mechanisms are probably also influenced by other lifestyle and biological factors.
Breast cancer is the most common cancer in women worldwide. It accounts for 25% of all new cancer cases in women. This report is an update of a previous report published in 2010. This report provides analysis of currently available scientific evidence regarding breast cancer and the association with different lifestyle factor, including alcohol.
Following this report, Prof Sir David Spiegelhalter (Winton Professor for the Public Understanding of Risk, University of Cambrigde) says: “…older women who drink moderately have lower death rates than similar women who don’t drink at all. But this study focuses only on the risks of breast cancer and so gives a very different impression.” Prof. Kevin McConway (Emeritus Professor of Applied Statistics, The Open University) indicates that “Like many cancers, breast cancer isn’t generally caused by something simple like getting an infection or having an injury – different factors have to act together.” He adds “taking their data at face value, the effect on breast cancer, while it looks real to me, isn’t huge. … Any increase is a bad thing, but it’s only one more [cancer case caused by alcohol consumption] out of the 100 women, and that has to be set against whatever pleasure the women might obtain from their drinking.”2
1. World Cancer Research Fund/American Institute for Cancer Research. Continuous Update Project Report: Diet, Nutrition, Physical Activity and Breast Cancer 2017.