Peripheral Bone Mineral Density and Bone Turnover in Postmenopausal Women with Type 2 Diabetes

Objective: Several studies have suggested that diabetes affects Bone Mineral Density (BMD). In this study, we investigated the effect of type 2 diabetes mellitus (T2DM) on BMD and the rate of bone turnover in postmenopausal women. Methods: This is a cross-sectional study, in which we measured peripheral bone density and markers of bone turnover in 60 postmenopausal women with T2DM and 48 age, alcohol intake and physical activity - matched control postmenopausal women without diabetes. Results: BMD was significantly greater in subjects with T2DM than controls (0.51 gm/cm2 vs. 0.47 gm/cm2, p<0.01). Women with T2DM also had higher Body Mass Index (BMI) than the control group (mean: 33.7 kg/m2 vs. 26.7 kg/m2, p<0.0001). The difference in BMD between the two groups became non-significant after adjusting for the effect of BMI by multiple regression analysis (p=0.091). Osteocalcin, a marker of bone formation and three markers of bone resorption (cross-linked-N-telopeptides [NTX], C-telopeptides of type 1 collagen [CTX], and Helical peptide) were significantly reduced in T2DM compared with controls. However, the difference in the three bone resorption markers also became insignificant after adjusting for BMI. Conclusion: This study has shown that postmenopausal women with type 2 Diabetes Mellitus apparently have higher BMD and slow bone turnover when compared with matched controls. However, the difference in BMD between the two groups became non-significant after adjusting for the effect of BMI. This study therefore does not provide evidence that T2DM per se affects bone mineral density in postmenopausal women.