Study confirms breast cancer link to low alcohol use

November 2014

A newly published study from the National Drug Research Institute (NDRI) and the Centre for Addictions Research of BC (CARBC) at the University of Victoria in Canada confirms that moderate drinkers have an increased risk of breast cancer. The study shows that consuming an average of up to two drinks a day is associated with an 8.5 percent increase in the risk, compared to abstaining from alcohol.

Previous research investigating the relationship between low-dose alcohol use and breast cancer has sometimes produced conflicting results. Some studies found no increased risk from low-dose or "moderate" drinking. This new study, co-authored by NDRI’s Tanya Chikritzhs, CARBC director Tim Stockwell, and former CARBC researcher Cornelia Zeisser, and published in Alcoholism: Clinical and Experimental Research, analysed 60 studies done before 2013.

Of those 60, only six were free of potentially serious biases; many because former drinkers were misclassified as abstainers, while other studies misclassified occasional drinkers as abstainers. This last bias in particular resulted in an underestimation of the risk of disease, the study shows. When corrected for these biases, the findings confirmed a significantly increased risk for breast cancer from low-dose consumption.

According to international studies, 5 to 10 percent of breast cancer deaths are attributable to alcohol.

“These results should encourage caution with alcohol consumption,” Professor Chikritzhs said. 

“Drinking within low-risk drinking guidelines is associated with a very small increase in risk of breast cancer as well as of some other cancers. In general, less drinking means less risk to health.”

The study can be downloaded from http://onlinelibrary.wiley.com/doi/10.1111/acer.12479/pdf