What is the effect of alcohol consumption on a women's risk for breast cancer?

Updated: Dec 26, 2019
  • Author: Graham A Colditz, MD, DrPH; Chief Editor: Chandandeep Nagi, MD  more...
  • Print
Answer

Answer

Substantial evidence now supports a positive association between alcohol consumption and breast cancer risk. In a pooled analysis of case-control and cohort studies (58,515 cases of breast cancer), women consuming 35-44 g/day of alcohol (about 3 drinks per day) had a RR of 1.32 (1.19-1.45) compared to nondrinkers. The risk increased by 7.1% (95% CI, 5.5%-8.7%) for each 10 g/day. [59]

Similar results were observed in a pooled analysis of the 6 largest cohort studies that allowed for additional control for other dietary factors. The risk of breast cancer increased monotonically with increasing intake of alcohol, with no statistical evidence of heterogeneity among studies. For a 10-g/day increase in alcohol, breast cancer risk increased by 9% (4%-13%). Adjustment for known breast cancer risk factors and dietary variables hypothesized to be related to breast cancer had little impact on the association with alcohol. In the collective literature, beer, wine, and liquor all contribute to the positive association, strongly suggesting that alcohol per se is responsible for the increased risk.

In intervention studies, consumption of approximately two alcoholic drinks per day increased total and bioavailable estrogen levels in premenopausal women, and single doses of alcohol acutely increased plasma estradiol levels in postmenopausal women, suggesting a mechanism by which alcohol may increase breast cancer risk.

In several large prospective studies, high intake of folic acid appeared to completely mitigate the excess risk of breast cancer due to alcohol, although folic acid intake was not associated with breast cancer risk among nondrinkers. This relationship was confirmed using plasma folic acid levels. [60] Because alcohol inactivates folic acid metabolites and low folate levels are associated with increased misincorporation of uracil into DNA, this finding suggests another possible mechanism for the adverse effects of alcohol.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!