Impact of Glycaemic Control on Bone Metabolism in Adult Patients with Type 1 Diabetes Mellitus

Abstract

Introduction: Type 1 diabetes mellitus (T1DM) is associated with reduced bone mineral density (BMD), increased bone turnover and impaired bone microarchitecture. However, data regarding the influence of glycaemic control on bone metabolism are limited. The aim of this study was to evaluate BMD and bone remodeling markers in patients with T1DM in relation to changes in glycaemic control. Methods/Design: We studied 118 patients with T1DM and age 20-50 years (mean 34.6±7.9years, M/F:53/65), diabetes duration >5 years and no diabetic complications and 95 healthy controls matched for age, sex and body mass index (BMI). All T1DM participants were re-examined after one-year (FU). In both groups, measurements of glycated hemoglobin (HbA1c) and BMD at lumbar spine (LS) and femoral neck (FN) by dual energy X-ray absorptiometry (DXA) were performed. Bone resorption and formation was assessed by measurements of β-crosslaps and of type 1 procollagen total N-terminal propeptide (TP1NP) in serum. Currently, seventy T1DM patients completed the FU and had repeat biochemical and BMD measurements. Based on current literature, BMD changes of ≥3% at the LS and of ≥6% at the FN were considered significant. Results: In the T1DM group, mean duration of the disease was 15.9±7.6 years and mean HbA1c was 8.1±1.4%. Subject in the T1DM group had lower BMD and Z-score at LS and FN compared to those in the control group (LS:p=0.039,p=0.02) (FN:p=0.041,p=0.038). At baseline, no significant differences in β-crosslaps and TP1NP were observed between the two groups. Out of the 70 T1DM patient who have completed FU so far, 42/70 patients had ≥0.5% reduction in HbA1c, 12/70 had about the same HbA1c (±0.4%) and 16/70 had ≥0.5% increase in HbA1c. In the 42 patients with improved HbA1c, BMD increased by 3.4% at the LS and by 5.7% at the FN, and TP1NP was significantly higher compared to baseline (p=0.043). Conclusion: T1DM is associated with reduced BMD but improvement of glycaemic control appears to ameliorate BMD and bone turnover. Disclosure E. Barmpa: None. M. Vlychou: None. S. Tigas: None. G.N. Koukoulis: None. A. Bargiota: None.