Axial BMD in Diabetic and Nondiabetic Southeast Asians with HIP Fractures: Do Race and Body Mass Index Matter?

Abstract

Obesity is less prevalent in Asian subjects with type 2 diabetes mellitus (T2DM) in contrast to Caucasians. Whether higher axial bone mineral density (BMD) often reported in T2DM is independent of body mass index (BMI) has not been clearly shown. BMD characterization in T2DM patients with hip fractures has also not been performed. We compared the BMD of Asian diabetic and nondiabetic patients with new hip fractures and explored how BMD was influenced by BMI. We included 255 diabetic and 148 nondiabetic patients. BMD adjusted for age; BMI; race; sex; renal function; and use of statins, proton pump inhibitors, steroids, anticonvulsants, and calcium and/or vitamin D supplements were compared between the groups. We were particularly interested in the BMD comparison between underweight diabetics and nondiabetics with hip fractures. The presence of T2DM was associated with higher BMD (g/cm(2)) at the femoral neck (0.527 ± 0.103 vs. 0.491 ± 0.102, P<.01) and lumbar spine [LS] (0.798 ± 0.147 vs. 0.723 ± 0.156, P<.01). This association persisted after adjustment for multiple confounding variables including BMI. The age-, BMI-, and sex-adjusted LS BMD was higher in underweight (BMI <18.5 kg/m(2)) diabetics compared to similar weight nondiabetics (0.733 ± 0.126 vs. 0.649 ± 0.131 g/cm(2), P = .014). T2DM is independently associated with higher axial BMD in patients with new hip fractures. The finding of higher BMD even in underweight diabetics with hip fractures compared to their nondiabetic counterparts suggests that higher BMD in subjects with T2DM is not due to higher BMI. BMD = bone mineral density BMI = body mass index CV = coefficient of variation DXA = dual-energy X-ray absorptiometry HbA1c = glycated hemoglobin IGF-1 = insulin growth factor-1 LS = lumbar spine 25(OH)D = 25-hydroxyvitamin D T2DM = type 2 diabetes mellitus.