Background: Little is known about the relationship between alcohol intake and breast cancer risk among Mexican women. This association may be modified by folate and Vitamin B12.
Methods: A population-based case-control study conducted in Mexico recruited 1,000 incident breast cancer cases aged 35-69 and 1,074 controls matched on age, region, and health care system. In-person interviews were conducted to assess breast cancer risk factors and recent diet using a food frequency questionnaire. Conditional logistic regression models estimated adjusted odds ratios and 95% confidence intervals.
Results: Over one-half (57%) of cases and less than one-half of controls (45%) reported any lifetime alcohol consumption. Compared with never drinkers, women reporting ever drinking (Adjusted OR = 1.25, 95% CI = 0.99-1.58) had a greater odds of breast cancer. There was evidence for interaction in the association between ever consuming any alcohol and breast cancer by folate (p for interaction = 0.04) suggesting women with lower folate intake had a higher odds of breast cancer (Adjusted OR = 1.99, 95% CI = 1.26-3.16) compared to women with higher folate intake (OR = 1.12, 95% CI = 0.69-1.83).
Conclusions: Our findings support evidence that any alcohol intake increases risk of breast cancer. Insufficient intake of folate may further elevate risk for developing breast cancer among women who consume alcohol.