Background: The disturbance of the GH-IGF-axis in type 1 diabetes (T1DM) with low circulating IGF-I, GH hypersecretion, and hyperinsulinemia, which may be associated with high tissue IGF-I, have implications on long-term vascular complications.
Objective and hypotheses: To establish disease, sex and age related serum IGF-I reference values for children with T1DM and test the hypothesis that IGF-I SDS is lower in T1DM than in healthy controls and negatively correlated to HbA1c, age, diabetes duration, and BMI.
Method: Annual IGF-I values were obtained from children and adolescents with T1DM. A total of 2,683 serum IGF-I values from 806 children were collected for up to 6 consecutive years.
Results: Diabetes, sex and age related IGF-I SDS values were negatively correlated to HbA1c, age, and diabetes duration, but positively correlated to BMI. Children and adolescents with T1DM had lower mean IGF-I levels as well as lower cut-offs (±2 SD) compared to healthy subjects. In boys with T1DM, mean IGF-I levels were −1.04 SD calculated from the healthy reference. IGF-I peaked at 15 years of age, similar to healthy controls, but with markedly lower levels in late puberty. Girls were more affected at later stages of puberty but with a slightly less depressed overall mean IGF-I of −0.69 SD. There was no correlation between IGF-I SDS and final height SDS or distance to TH SDS.
Conclusion: We have established an IGF-I reference for children with T1DM and demonstrated that poor metabolic control and diabetes duration impact negatively on serum IGF-I levels. Low serum IGF-I may further elevate GH and increase insulin in extra-hepatic tissues leading to high tissue IGF-I and progression of vascular complications. IGF-I SDS may become a complement to HbA1c in predicting long term outcomes in T1DM.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology