Relevance of IGF-I, IGFBP-3, and IGFBP-2 measurements during GH treatment of GH-deficient and non-GH-deficient children and adolescents.
BACKGROUND
Little information is available on the relevance of parameters representing the insulin-like growth factor (IGF) system with regard to growth hormone (GH) treatment during childhood. In adults, high IGF-I levels were found to be associated with side effects and long-term risks.


OBJECTIVE
Our aim was to monitor the serum levels of IGF-I, IGF-binding protein (IGFBP) 3, and IGFBP-2 during long-term GH treatment of 156 patients with GH deficiency (GHD) and of 153 non-GHD patients. We determined the extent to which the IGF parameters exceed the normal ranges and identified those parameters which are predictive of 1st-year growth.


RESULTS
In prepubertal GHD children, the levels of IGF-I, IGFBP-3, and IGF-I/IGFBP-3 exceeded the 95th centile of the reference values for this age group in 2.3, 0.3, and 7.9% of the cases, respectively, whereas in prepubertal non-GHD children, the same parameters exceeded the 95th reference centile in 20.1, 3.5, and 32.2%, respectively. In pubertal GHD children IGF-I, IGFBP-3, and IGF-I/IGFBP-3 levels exceeded the 95th reference centile in 11.1, 1.5, and 15.4%, respectively. In pubertal non-GHD children, these levels also exceeded the 95th centile in 26.7, 7.0, and 41.4%, respectively. In both GHD and non-GHD groups, however, some patients had IGF parameters which were below the reference values. Our analysis showed that, in both groups, in addition to maximum GH, all IGF parameters (IGF-I, IGFBP-3, IGF-I/IGFBP-3 ratio, IGFBP-2 or derivatives) significantly extend the scope of a calculated model for predicting 1st-year height velocity.


CONCLUSIONS
For reasons of safety and optimization of GH therapy, it is essential to follow up IGF-I, IGFBP-3, and IGFBP-2 levels regularly during childhood.
Ranke
M B
MB
Paediatric Endocrinology Section, University Children's Hospital, Hoppe-Seyler Strasse 1, D-72076 Tübingen, Germany. mlranke@med.uni-tuebingen.de
Schweizer
R
R
Elmlinger
M W
MW
Weber
K
K
Binder
G
G
Schwarze
C P
CP
Wollmann
H A
HA
D000293:Adolescent; D001827:Body Height; D002648:Child; D005260:Female; D006130:Growth Disorders / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D013006:Growth Hormone / Q000172:deficiency*; D019382:Human Growth Hormone / Q000627:therapeutic use*; D006801:Humans; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000097:blood* / Q000502:physiology; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood* / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000502:physiology; D008137:Longitudinal Studies; D008297:Male
D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone