To evaluate the influence of sexual gonadal function on the final adult height (FAH) in growth hormone (GH)-treated growth hormone deficiency (GHD) children.

From October 1993 to August 2004, 15 children with growth hormone deficiency who reached final adult height(FAH)after receiving recombinant human growth hormone (rhGH) treatment were included in this study. They were divided into two groups, spontaneous puberty development group (n=9, 5 boys and 4 girls) and induced puberty group (n=6, 3 boys and 3 girls). Informed consent was obtained from all participates. All cases of induced puberty group had low sex gland function, among them, 5 were central hypothyroidism. All these 5 cases were treated with thyroid tablet or levothyroxine sodium replacement therapy until serum T3, T4 levels back to the normal, then they began recombinant human growth hormone treatment. The approach of recombinant human growth hormone treatment were the following steps, subcutaneous injections of recombinant human growth hormone 0.7 IU/(kg·w)[0.23 mg/(kg·w)] before sleep for 1.1 to 7.7 years. Regular follow-up observation was taken after treatment. Final adult height was defined as a bone age(BA) ≥16 years for boys and ≥14 years for girls or the growth rate(GV) <2 cm/year. Final adult height, factors determining final adult height and pubertal growth factors were evaluated.

Standard deviation score (SDS) of final adult height were (-1.13±0.54) in spontaneous puberty development group and(-1.00±0.47) in induced puberty group. Corrected for genetic target height (THt) of standard deviation score of final adult height were (-0.33±0.58) and (0.04±0.62) for spontaneous puberty development group and induced puberty group, respectively. A total of 77.8% (7/9) of spontaneous puberty development group and all induced puberty group achieved final adult height which was comparable to or above their target height. There had no statistic significance difference of standard deviation score of final adult height and genetic target height of standard deviation score (THt-SDS) between two groups (P>0.05). Standard deviation score of final adult height in spontaneous puberty development group was positively correlated with the growth velocity at the first year of therapy, height standard deviation score at initiation of the treatment determined by age, height standard deviation score at the beginning of puberty, genetic target height of standard deviation score, however, negative correlation was found among the above variables in induced puberty group. Age at puberty of spontaneous puberty development group were (12.98±0.59) years old for boys and (10.75±0.84) years old for girls, and the development age induced by growth hormone in induced puberty group were (21.92±5.81) years old and (19.44±0.68) years old. There had a significant difference between two groups (P<0.05). Adolescent height gain of spontaneous puberty development group were (24.38±1.86)cm for boys and (22.47±2.65) cm for girls, which accounted for (14.91±1.15)% and (15.21±1.43)% of final adult height, respectively. Adolescent height gain of induced puberty group were (3.07±2.64) cm for boys and (3.63±2.18) cm for girls, which accounted for (1.86±1.61)% and (2.35±1.40)%, respectively.

Growth hormone deficiency children who were treated by recombinant human growth hormone could improve gonadal function which can influence the final adult height of growth hormone deficiency children. Induced puberty children who start recombinant human growth hormone treatment late and height significantly behind normal children at the beginning of the therapy can receive delayed induction of puberty age method to improve final adult height.