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.
PIP: A group of 310 normal, healthy Chinese children (137 boys and 173 girls) ranging in age from 5 days to 12 days were selected from the nursery, well-baby clinic, kindergarten. and primary school. The patients with classical growth hormone deficiency consisted of 13 children (10 boys and 3 girls) between the ages of 6 and 12 years. 2 patients had been operated on for craniopharyngioma, and 11 children had idiopathic hypopituitarism. The determination of serum insulin-like growth-I (IGF-I) levels was done when they were euthyroid. The mean serum IGF-I levels in both males and females aged below 3 years were significantly lower than those of any other age group. The next significant increment in serum IGF-I levels ocurred at 8-10 years in females and 10-12 years in males. The mean serum IGF-I concentration in girls aged 6-8 years or younger and boys aged 8-10 years or younger were significantly lower than those in normal adult females or males. Also, the mean IGF-I levels in the serum of girls were higher than those in boys in all age groups; however, the differences were statistically significant only at 8-10 years and 10-12 years of age. All of the 13 children with classical growth hormone deficiency had serum IGF-I levels lower than the range for their sex- and age-matched peers, but the serum IGF-I concentrations did not change with age. The serum IGF-I levels in children under 3 years were only about one-third of the adult values, and there was a significant rise in the serum IGF-I concentrations after 3 years of age in both sexes. The mean serum IGF-I levels in the different age groups did not reach adult levels until around 10 years of age. Serum IGF-I levels in normal adults cannot be used as a reference for diagnostic comparison of serum IGF-I levels in prepubertal children; however, the determination of the serum IGF-I concentration is of value in the diagnosis of growth hormone deficiency in Chinese children.