Clinical and endocrine correlates of circulating sclerostin levels in patients with type 1 diabetes mellitus

Summary Aim Type 1 diabetes mellitus ( T 1 DM ) increases fragility fractures due to low bone mass, micro‐architectural alterations and decreased bone formation. Sclerostin is expressed by osteocytes and inhibits osteoblastic bone formation. We evaluated serum sclerostin levels in T 1 DM and their association with bone mineral density ( BMD ), bone turnover, glycaemic control and physical activity. Patients and Methods In a cross‐sectional study, 128 men and premenopausal women with long‐standing T 1 DM (mean age 43·4 ± 8·8 years, diabetes duration 22·4 ± 9·5 years) and 77 age‐, BMI (Body Mass Index) and gender‐matched healthy individuals were evaluated. Results Serum sclerostin levels were higher in T 1 DM compared with controls, irrespective of gender (male 0·55 ± 0·17 vs 0·49 ± 0·12 ng/ml, P  =   0·046; female 0·52 ± 0·19 ng/ml vs 0·43 ± 0·12 ng/ml, P  =   0·012). Partial correlation analysis adjusted for age and gender revealed a positive correlation between serum sclerostin levels and BMD at lumbar spine and femoral neck in T 1 DM and between BMD at lumbar spine, femoral neck and total hip in controls. Bone turnover markers, parathyroid hormone, calcium and vitamin D did not correlate with serum sclerostin levels in T 1 DM or controls. Physical activity was not associated with serum sclerostin levels. A multivariate analysis revealed that only the interaction of T 1 DM and age affects serum sclerostin levels but not T 1 DM alone. The influence of age on serum sclerostin levels was more pronounced in T 1 DM compared with controls. Conclusions Sclerostin serum levels were increased in patients with T 1 DM , and the positive correlation of age with serum sclerostin levels was stronger in T 1 DM . There was no effect of serum sclerostin levels on markers of bone metabolism and they do not explain the detrimental effects of T 1 DM on BMD .