High Sclerostin and Dickkopf-1 (DKK-1) serum levels in children and adolescents with type 1 diabetes mellitus

CONTEXT: Childhood type 1 diabetes (T1DM) is associated with decreased bone mass. Sclerostin and dickkopf-1 (DKK-1) are Wnt inhibitors which regulate bone formation. OBJECTIVE: To evaluate sclerostin and DKK-1 levels in TD1M children and to analyze the influence of the glycaemic control on bone health. DESIGN AND SETTING: Cross-sectional study conducted at a clinical research center. Partecipants: One hundred and six T1DM subjects (12.2 ± 4 years), 66 on multiple daily injections (MDI) and 40 on continuous subcutaneous infusion of insulin (CSII), and 80 controls. RESULTS: The average of bone transmission time (BTT) and amplitude-dependent speed of sound (Ad-Sos) Z-scores was lower in diabetics than controls. Significant increased DKK-1 (3593 ± 1172 vs 2652 ± 689 pg/ml, p<0.006) and sclerostin (29.45 ± 12.32 vs 22.53 ± 8.29, p<0.001) levels were found in diabetics respect to controls, particularly in patients on MDI than ones on CSII. Glycaemic control was improved in CSII patients compared to MDI ones (p<0.001) and was also associated to a significant higher BMI-SDS (p<0.002) and BTT-Z-score (p<0.02). With adjustment for age multiple linear regression analysis for DKK-1 and sclerostin as dependent variables showed that levels of HbA1c%, glucose, 25(OH)-Vitamin D, osteocalcin, PTH, years of diabetes, BMI-SDS and AD-SoS-Z-score are the most important predictors (p<0.0001). CONCLUSIONS: Our study highlighted: 1. the high serum levels of DKK-1 and sclerostin in T1DM children, and their relationship with the altered glycaemic control; 2. the effect of CSII on the improvement of glycaemic control and bone health in T1DM children.