Dairy Intake is Not Associated with Improvements in Bone Mineral Density or Risk of Fractures Across the Menopause Transition: Data from the Study of Women's Health Across the Nation

Objective: Menopause represents a period in which bone deterioration is accelerated; thus, primary prevention strategies to address age-related bone loss are crucial. Dairy products contain more than a dozen essential nutrients, including calcium, phosphorus, vitamin D, and high-quality protein, as well as bioactive compounds that may promote bone mineralization. However, the relationship between dairy consumption and bone health across the menopause transition remains largely unknown. The purpose of this analysis was to estimate the change in lumbar spine and femoral neck bone mineral density and the risk of bone fracture by the frequency of dairy intakes among women across the menopausal transition using the publicly available data from the Study of Women's Health Across the Nation.

Methods: We analyzed total dairy foods in four categories of <0.5, 0.5 to <1.5, 1.5 to <2.5, and ≥2.5 servings/d or <1.5 and ≥1.5 servings/d. A general linear model was used to estimate the association of dairy intake with the 10-year bone mineral density loss rate and a linear mixed model was used to estimate the annualized bone mineral density loss rate of the femoral neck and lumbar spine. A Cox proportional hazard model was applied to calculate hazard ratios and 95% confidence intervals of the nontraumatic fractures. Poisson regression was used to determine the relative risks and 95% confidence intervals of the nontraumatic fractures. The models were controlled for race/ethnicity, age, height, weight, smoking status, physical activity, alcohol consumption, calcium use, menopausal status, and total caloric intake.

Results: No significant differences in bone mineral density change were observed, regardless of baseline menopausal status. No significant differences in the risk of nontraumatic fracture were observed.

Conclusions: In this group of US women undergoing the menopausal transition, dairy food intake was neither associated with femoral and spine bone mineral density loss nor the risk of fractures.