Reference values for serum levels of insulin-like growth factor-I and insulin-like growth factor binding protein-3 in Korean children and adolescents.
OBJECTIVE
Measurements of serum insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) are utilized in the diagnostic work-up and clinical management of children with growth disorders. We designed this study to establish the reference values of serum IGF-I and IGFBP-3 levels according to age, sex and pubertal stage in Korean children and adolescents.


METHODS
For the study, 1378 healthy Korean children and adolescents aged 0 to 17 years (722 boys, 656 girls) were randomly selected. Blood samples were collected, and the stored sera were assayed for IGF-I and IGFBP-3 using immunoradiometric assay (IRMA, Immunotech). The R 2.8.1 program (Bell Laboratories) was used to generate reference percentile curves for IGF-I and IGFBP-3 according to age, sex, and pubertal stage


RESULTS
Serum IGFBP-3 level was higher in girls compared to that in boys of the same ages throughout the pubertal period, whereas IGF-I was only higher for girls younger than 13 years of age. Serum levels of IGF-I and IGFBP-3 increased steadily with age in the prepubertal stage, followed by a progressive decline thereafter. Peak levels of serum IGF-I and IGFBP-3 were observed two years earlier in girls compared to those in boys (13 vs. 15 years of age, respectively). Serum IGF-I and IGFBP-3 concentrations were highest at Tanner stage IV in boys and girls, with a subsequent decline.


CONCLUSIONS
Our reference value model based on age, sex, and pubertal stage can improve the diagnostic utility of IGF-1 and IGFBP-3 levels in the evaluation and management of Korean children and adolescents with growth disorders.
Department of Pediatrics, Institute of Endocrinology, College of Medicine, Yonsei University, Republic of Korea.
Sei Eun
SE
Hyun
Byung Churl
BC
Lee
Byung Kyu
BK
Suh
So Chung
SC
Chung
Cheol Woo
CW
Ko
Heung Sik
HS
Kim
Kee Hyoung
KH
Lee
Sei Won
SW
Yang
Choong Ho
CH
Shin
Jin Soon
JS
Hwang
Duk Hee
DH
Kim
Baek Keun
BK
Lim
Jong Duck
JD
Kim
Han-Wook
HW
Yoo
Hye Soon
HS
Kim
Woo Yeong
WY
Chung
Mi Jung
MJ
Park
Young Jong
YJ
Woo
Chan Jong
CJ
Kim
Dae-Yeol
DY
Lee
Eun Young
EY
Kim
Jin Ho
JH
Choi
Heon Seok
HS
Han
Il Tae
IT
Hwang
Ho-Seong
HS
Kim
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006130:Growth Disorders / Q000097:blood; D006801:Humans; D015592:Immunoradiometric Assay / Q000379:methods; D007223:Infant; D007231:Infant, Newborn; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D007723:Korea; D008297:Male; D012016:Reference Values
D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I