Glycemic control and bone metabolism in postmenopausal women with type 2 diabetes mellitus

Objective Diabetes mellitus type 2 (T2DM) has accumulated attention as a fracture risk in osteoporosis. In the present study, we investigated the effect of glycemic level, its control, and its treatment on bone mineral density (BMD) and bone metabolism focusing on Japanese postmenopausal women with T2DM. Methods BMD was determined by dual-energy X-ray absorptiometry to calculate T score and Z score at the lumbar spine at L2-4. Bone metabolic markers such as serum type 1 collagen cross-linked N-telopeptides (sNTX), a marker of bone resorption, and serum bone-specific alkaline phosphatase (BAP), a marker of bone formation, were measured. Results We enrolled 55 Japanese postmenopausal women with T2DM [initial age 63.5 +/- 7.7 years, BMI 22.8 +/- 3.5 kg/m(2), hemoglobin A(1c) (HbA(1c)) 7.53 +/- 1.94% (HbA(1c) Japanese Diabetes Society; JDS) 7.26 +/- 1.68%], L2-4BMD 0.927 +/- 0.169 g/cm(2), T score -0.738 +/- 1.527; Z score 0.945 +/- 1.272]. There were no significant differences on L2-4 BMD, T score, Z score, or bone metabolic markers among three treatment groups regarding diet, orally administered medication, and insulin. In the analysis of correlation coefficients, HbA1c significantly correlated with sNTX (r = 0.363, p = 0.008), and the significant, but weak, correlation was observed between HbA1c and Z score (r = 0.306, p = 0.026). In patients newly treated with intensive insulin therapy (n = 5), glycemic control significantly suppressed sNTX after 3 months (p < 0.05). Conclusions The control of glycemic level might be correlated with osteoclast function in terms of bone resorption marker, which might be linked with fracture risk in postmenopausal women with T2DM.