Does Folate Intake Modify the Association between Alcohol and Breast Cancer Risk?

Research has shown an association between alcohol consumption and breast cancer risk. Some studies suggest folate may modify this risk. Investigators examined data from 88,530 postmenopausal women participating in the US Women’s Health Initiative Observational Study to assess the relationship between breast cancer, alcohol consumption, and folate. Between 1993 and 1998, participants aged 50–79 years completed baseline questionnaires assessing alcohol and folate intake as well as breast cancer risk factors. Cox proportional hazards analysis was used to examine the relationship between alcohol, folate intake, and incident breast cancer over a mean follow-up period of 5.5 years. During that time,

• 1783 breast cancer cases occurred.

• breast cancer risk increased with greater consumption (≤5 g alcohol per day, adjusted hazard ratio [HR], 1.10; >5–15 g per day, HR, 1.14; >15 g per day, HR, 1.13).

• no significant interaction between alcohol and folate was seen in adjusted models.

Comments:

This well-done analysis found no evidence that folate intake reduces breast cancer risk in postmenopausal women who consume alcohol. Most of the potential confounding variables (e.g., positive family history, use of hormone supplements, early menarche) showed the expected positive association with breast cancer risk, and the association with alcohol intake was similar to that shown in other studies (roughly a 6% increase in risk per typical 12 g drink per day). However, recruitment for this study occurred after the fortification of cereals and grains with folate in the US, which could have resulted in fewer women with inadequate intake. Further, the relatively brief follow-up period may not have been adequate to demonstrate a protective effect.

R. Curtis Ellison, MD

Reference:

Duffy CM, Assaf A, Cyr M, et al. Alcohol and folate intake and breast cancer risk in the WHI Observational Study. Breast Cancer Res Treat. 2009;116(3):551– 562.