Variation in the association of alcohol intake with uterine fibroids by race and tumor size

Purpose Uterine fibroids are prevalent benign tumors and are the leading indication for hysterectomy in the United States. Hormonal dependence for development and growth of these tumors suggests the role of estrogen-promoting factors. Alcohol intake has been associated with higher concentrations of estrogen among premenopausal women and has been implicated in other hormonally related conditions, including breast cancer. We hypothesized that alcohol intake is associated with an increased risk of uterine fibroids. Methods The study population consisted of 1146 premenopausal black or white women from the NIEHS Uterine Fibroid Study. Participants were randomly selected 35- to 49-year-old members of an urban health plan. Assessment of uterine fibroids was performed primarily through transvaginal ultrasounds. Race-stratified unconditional logistic regression was used to calculate prevalence odds ratios (OR) and 95% confidence intervals (CI) for the association of uterine fibroids with self-reported current alcohol intake and intake at age 30. Race-stratified polytomous logistic regression was used to assess these relationships with small (0.5 to <2 cm), medium (2–3.99 cm), and large (≥4 cm) tumors. Estimates were adjusted for age, vigorous exercise, age at menarche, parity, and body mass index. Results For white women, the odds of uterine fibroids were 90% greater (95% CI = 1.0, 3.5) among those currently consuming at least 0.5 alcoholic drinks weekly compared with nondrinkers. The odds ratio with current drinking was strongest for small fibroids (OR = 4.3; 95% CI = 1.4, 12.9), and alcohol intake at age 30 was most strongly related to large tumors (OR = 1.5; 95% CI = 0.6, 3.7). There was no association of alcohol intake with uterine fibroids for black women (OR = 1.0; 95% CI = 0.7, 1.6), but the patterns for current and past drinking with fibroid size were generally similar to those for white women. Conclusion This study suggests the involvement of alcohol intake in the initiation or early growth of uterine fibroids.