Concentrations of serum insulin-like growth factor-I (IGF-I) in normal Chinese children and children with growth hormone deficiency.

In order to establish the range of the serum insulin-like growth factor-I (IGF-I) concentrations for various ages in normal Chinese children and to evaluate the use of IGF-I levels in the diagnosis of classical growth hormone deficiency, the serum concentrations of IGF-I of 310 normal Chinese children (137 boys and 173 girls) and 13 children (10 boys and three girls) with classical growth hormone deficiency were determined. In this study, we divided normal subjects of each sex into five age groups. In both sexes, an increase in the mean IGF-I levels of normal children was statistically significant around the age of three and at the age corresponding to the onset of puberty. The mean IGF-I levels in the serum of girls were higher than those in boys at all ages. However, the differences were statistically significant only at 8-10 and 10-12 years of age. The serum IGF-I concentrations of 13 patients with classical growth hormone deficiency ranged from undetectable to 78 ng/mL, and all of their IGF-I levels were lower than the normal range for their age. Because of the low IGF-I concentrations in the serum of normal children younger than three years of age, its clinical application in this age group is limited. From this study, we conclude that the determination of serum IGF-I concentrations is of clinical value in the diagnosis of growth hormone deficiency in Chinese children over three years of age.