Sexual dimorphism in growth and insulin-like growth factor-I in children with type 1 diabetes mellitus.

Objective: Impaired linear growth and reduced IGF-I levels in children with type 1 diabetes (T1DM) have been related to poor metabolic control. The aim of this study was to identify additional factors which may negatively affect growth and IGF system in patients with T1DM.
Design: Ninety-one T1DM children (54 males, age=: 11.73±3years, disease duration=5.6±2.1years) were studied. All children were on intensive insulin therapy: 62 children were on multiple injection therapy (MI) and 29 children on continuous subcutaneous insulin infusion (CSII).
Results: Height velocity (HV) SDS and IGF-I levels were higher in females and in pubertal children [HV SDS: females=0.6±2.4 vs males=-0.45±2.3 (p=0.04); IGF-I SDS: females=-1.09±0.58 vs males=-1.4±0.6 (p=0.02); IGF-I/IGFBP-3 molar ratio: females=0.25±0.1 vs males=0.21±0.08 (p=0.04); IGF-I SDS: pre-pubertal=-1.58±0.46 vs pubertal=-1.15±0.65 (p<0.001); IGF-I/IGFBP-3 molar ratio: pre-pubertal=0.16±0.08 vs pubertal=0.26±0.09 (p<0.001)]. No differences between children on CSII or MI therapy were found. IGF-I SDS was positively related to C peptide level (p<0.001), puberty (p<0.001) and female gender (p=0.02) and negatively related to HbA1c (p=0.04). IGF-I/IGFBP-3 molar ratio was positively affected by C peptide level (p<0.001), puberty (p<0.001) and daily insulin dose (p<0.001).
Conclusions: Our results indicate that despite intensive insulin therapy, T1DM still negatively affects IGF-I secretion and linear growth. Growth impairment is more severe in males and primarily related to poor glycemic control and loss of the residual beta cell mass.
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