Five year change in alcohol intake and risk of breast cancer and coronary heart disease among postmenopausal women: prospective cohort study

Authors: Dam MK et. al.

Source: BMJ 2016;353:i2314 (doi:10.1136/bmj.i2314)

www.bmj.com/content/353/bmj.i2314

Alcohol consumption has known links to breast cancer and coronary artery disease.  Breast cancer risk increases with alcohol intake, while coronary artery disease risk declines with light to moderate alcohol intake. Although these facts are widely known and used by care providers, the studies that support this information have structural flaws.

This study evaluated 21,523 postmenopausal women in Denmark. From 1993-1997 and from 1999-2003, the women were asked to report their average alcohol consumption for each year. Modeling was performed to ensure little to no variability regarding body mass index, education level, smoking history, diet, childbirth history and use of menopausal hormone replacement therapy. The subjects were observed for development of breast cancer and coronary artery disease. Follow up was about 11 years.

Investigators found that women with increased alcohol intake over the two time periods (from fewer than 7 drinks per week to 7-13 drinks per week) had a higher breast cancer risk compared to women whose alcohol consumption did not change between the two periods. Regarding coronary artery disease, women who increased their alcohol consumption (again, from fewer than 7 to 7-13 per week) had a lower risk than women whose consumption was unchanged between the time periods.

Interestingly, when women decreased their alcohol consumption, the risks of both diseases were not significantly affected.

This information supports the conventional understanding of the relationships between alcohol and breast cancer and alcohol and heart disease. The study can inform health care providers as they counsel their patients about the effects of alcohol consumption on specific diseases.