Evaluation of Growth Status Using Serum IGF-I and IGFBP-3 in Children with Subclinical Hypothyroidism

Purpose : The aim of this study was to evaluate growth status using the insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3) concentrations in children with subclinical hypothyroidism (SCH). Methods : The study included 93 SCH patients (33 males and 60 females, age 8.1±1.9 years) and 94 healthy control subjects (31 males and 63 females, age 8.0±0.7 years). Patients’ height and weight were measured, and their body mass index (BMI) and Z-scores were calculated. The relationship between growth parameters, including IGF-I and IGFBP-3 concentrations and thyroid functions (thyroid-stimulating hormone (TSH) and free thyroxine 4 (fT4) was explored. Results : Although weight and BMI were greater in SCH patients, the Z-score of height, weight and BMI, and serum IGF-I and IGFBP-3 levels in SCH children were not significantly different compared to the control. In SCH patients, TSH showed a negative correlation with weight Z-scores (r =-0.23, P =0.028) and BMI Z-scores (r =-0.21, P =0.048). FT4 showed a positive correlation with IGFBP-3. Conclusion : The positive correlation of fT4 and IGFBP-3 and the negative relationship between TSH and weight and BMI Z-scores in SCH children suggest that subnormal thyroid functions could be related to growth impairment. (J Korean Soc Pediatr Endocrinol 2011;16:31-37)