Abstract
Later menopause is a risk factor for breast and endometrial cancer, yet few studies have investigated dietary predictors of this potentially modifiable event. In particular, dairy contains hormones and growth factors that could potentially affect menopausal timing. We therefore assessed the association between regular consumption of dairy foods and related nutrients and age at natural menopause. We conducted a prospective analysis with up to 20 y of follow-up in 46,059 participants in the Nurses' Health Study who were premenopausal in 1980. We observed 30,816 events of natural menopause over 401,754 person-years. In the total population, the estimated mean age at natural menopause was 51.5 y for women who consumed no low-fat dairy and 51.5, 51.6, 51.7, and 51.8 y for women who consumed 0.1-1.0, 1.1-2.0, 2.1-3.0, and >3 servings of low-fat dairy daily, respectively. Premenopausal women <51 y of age consuming >3 servings of low-fat dairy per day were 14% less likely (HR: 0.86; 95% CI: 0.77, 0.96; P-trend < 0.0001) to report natural menopause in the next month relative to those consuming 0.1-1 servings/d. Similar results were obtained for skim milk (for >6 servings/wk vs. 0-1 servings/mo: HR: 0.93; 95% CI: 0.89, 0.97; P-trend < 0.0001) but not for total high-fat dairy or whole milk. Dairy foods were not associated with age at menopause among women ≥51 y of age. These findings support the growing body of literature on the hormonally active nature of milk and dairy foods.