Bone quality assessment in type 2 diabetes mellitus

Abstract

The increased risk for fractures in type 2 diabetes mellitus (T2DM) despite higher average bone density is unexplained. This study assessed trabecular bone quality in T2DM using the trabecular bone score (TBS). The salient findings are that TBS is decreased in T2DM and low TBS associates with worse glycemic control. Type 2 diabetes mellitus is a risk factor for osteoporotic fractures despite high average bone mineral density (BMD). The aim of this study was to compare BMD with a noninvasive assessment of trabecular microarchitecture, TBS, in women with T2DM. In a cross-sectional study, trabecular microarchitecture was examined in 57 women with T2DM and 43 women without diabetes, ages 30 to 90years. Lumbar spine BMD was measured by dual-emission x-ray absorptiometry (DXA), and TBS was calculated by examining pixel variations within the DXA images utilizing TBS iNsight software. Mean TBS was lower in T2DM (1.228 ± 0.140 vs. 1.298 ± 0.132, p = 0.013), irrespective of age. Mean BMD was higher in T2DM (1.150 ± 0.172 vs. 1.051 ± 0.125, p = 0.001). Within the T2DM group, TBS was higher (1.254 ± 0.148) in subjects with good glycemic control (A1c ≤ 7.5%) compared to those (1.166 ± 0.094; p = 0.01) with poor glycemic control (A1c > 7.5%). In T2DM, TBS is lower and associated with poor glycemic control. Abnormal trabecular microarchitecture may help explain the paradox of increased fractures at a higher BMD in T2DM. Further studies are needed to better understand the relationship between glycemic control and trabecular bone quality.