Femoral bone mineral density at the time of hip fracture is higher in women with versus without type 2 diabetes mellitus: a cross-sectional study.

PURPOSE: To compare femoral bone mineral density (BMD) levels in hip-fracture women with versus without type 2 diabetes mellitus (T2DM). We hypothesized that BMD levels could be higher in the women with T2DM than in controls and we aimed to quantify the BMD discrepancy associated with the presence of T2DM. METHODS: At a median of 20 days after the occurrence of an original hip fracture due to fragility we measured BMD by dual-energy x-ray absorptiometry at the non-fractured femur. RESULTS: We studied 751 women with subacute hip fracture. Femoral BMD was significantly higher in the 111 women with T2DM than in the 640 without diabetes: mean T-score between-group difference was 0.50, (95% CI from 0.30 to 0.69, P < 0.001). The association between the presence of T2DM and femoral BMD persisted after adjustment for age, body mass index, hip-fracture type, neurologic diseases, parathyroid hormone, 25-hydroxyvitamin D and estimated glomerular filtration rate (P < 0.001). For a woman without versus with T2DM, the adjusted odds ratio to have a femoral BMD T-score below the threshold of - 2.5 was 2.13 (95% CI from 1.33 to 3.42, P = 0.002). CONCLUSIONS: Fragility fractures of the hip occurred in women with T2DM at a femoral BMD level higher than in control women. In the clinical assessment of fracture risk, we support the adjustment based on the 0.5 BMD T-score difference between women with and without T2DM, although further data from robust longitudinal studies is needed to validate the BMD-based adjustment of fracture risk estimation.