Summary: The purpose of this study was to evaluate the rate of bone loss and incident fractures in women with diabetes mellitus (DM) across menopause. During menopause, DM women experienced bone mineral density (BMD) loss that was faster at hip and slower at spine and had a higher risk of fractures, perhaps because of their earlier menopause. The increasing DM epidemic will contribute to higher fracture burden.
Introduction: Women with DM have a higher risk of fractures independent of age, body mass index (BMI), and BMD. Our objective is to evaluate if women with DM experience greater bone loss and more fractures across menopause.
Methods: Two thousand one hundred seventy one women, aged 42 to 52 years at baseline (1996), enrolled in the Study of Women's Health Across the Nation (SWAN), a prospective study, with 8 years of annual follow up. One thousand three hundred forty six (62%) completed annual visit 7 (2004). Women with baseline fasting blood glucose level of ≥126 mg/dl and those being treated for diabetes were designated as DM. Annual assessment of menopausal stage, BMD, and urinary N-telopeptide (NTx) were carried out. Rate of change in BMD across menopause and annual self-report data for risk of incident fractures by DM status were determined.
Results: Despite higher baseline BMD at hip (p = <0.001), and lumbar spine (p = <0.001), rate of decline in BMD was faster at hip (β = -0.45 vs. -0.11 gm/cm(2)/year, p = <0.001) for DM women, compared to non-DM. However, lumbar spine bone loss was slower in women with DM as compared to non-DM women (β = 0.04 vs. -0.25 gm/cm(2)/year, p = 0.004). DM women experienced menopause 3 years earlier than non-DM women (p = 0.002), and age adjusted incident fractures were two fold higher in women with DM compared to non-DM (RR = 2.20, 95% CI: 1.26-3.85, p = <0.006).
Conclusions: BMD loss is greater in hip and slower at spine in DM women during menopausal transition. Women with DM have a higher risk of fractures, perhaps because of their earlier menopause.