There is no evidence that dairy intake affects the rate of bone mineral density (BMD) loss or fracture risk in women across the menopausal transition, according to the results of a study published in Menopause.
Longitudinal data from the Study of Women’s Health Across the Nation (SWAN) for women aged 42 to 53 years who had an intact uterus, at least 1 ovary, no hormone usage in the 3 months prior to screening, and no history of osteoporosis, diabetes, or cancer were used to examine the association of dairy intake levels with BMD changes during the menopausal transition. Women who had incomplete data or unknown menopausal status were excluded. Data from 1955 women were used in the annualized BMD loss rate analysis and data from 1109 and 1097 women were used in the 10-year femoral neck and lumbar spine BMD loss analyses, respectively.
Measurements of BMD at the femoral neck and lumbar spine were obtained annually for 10 years by dual-energy x-ray absorptiometry scans. Fractures that were reported up to year 6 were self-reported, whereas fractures that were reported in years 7 to 10 of follow-up were confirmed by radiology reports. Traumatic fractures, such as those resulting from an athletic event, and fractures that occurred in regions not typically associated with osteoporosis (toe, digit, and face fractures) were excluded from analysis.
Information regarding daily dairy intake and general eating habits in the year prior was collected through surveys at baseline, year 5, and year 9. The number of dairy servings consumed per day reported at each survey time point was carried forward for the subsequent years until the next survey was conducted or until the end of the study. The cumulative average of the number of daily dairy servings at all visits was used to categorize participating women into groups based on dairy intake (<0.5 serving, 0.5-<1.5 servings, 1.5-<2.5 servings, or ≥2.5 servings).
Menopausal status was based on annual questions regarding menstruation patterns, hormone therapy, pregnancy, breastfeeding, hysterectomy, and oophorectomy.
No significant differences in the mean rate of BMD loss at the femoral neck or lumbar spine over the 10-year period were observed between levels of dairy consumption, even after adjustment for potential confounding variables, and no significant difference in hazard ratios for nontraumatic fractures was observed among the varying levels of dairy consumption.
The results of this study support that average dairy consumption is not likely to influence the rate of BMD loss at the femoral neck or lumbar spine in women transitioning to postmenopause.
A limitation to this study was the relatively low dairy consumption among participants, especially among women who were not non-Hispanic white, as 65% of participating women reported consuming <1.5 servings per day.
Wallace TC, Jun S, Zou P, et al. 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 [published online May 11, 2020]. Menopause. doi:10.1097/GME.0000000000001555