Relationship between umbilical cord blood insulin-like growth factors and anthropometry in term newborns.
BACKGROUND
Birth size is associated with long-term morbidity. Insulin-like growth factor (IGF) system is the most important endocrine factor influencing fetal growth. During rapid somatic growth, free-to-total IGF-I ratio is increased, resulting in higher IGF-I bioavailability. The purpose of this study was to investigate the association of free-to-total IGF-I ratios, IGF-II, and IGF-binding protein (IGFBP)-3 umbilical cord levels with anthropometric data of term neonates.


METHODS
Umbilical venous plasma samples were obtained from 95 term neonates and analyzed by enzyme-linked immunosorbent assay.


RESULTS
The large-for-gestational age (LGA) neonates had higher free IGF-I, total IGF-I, and IGFBP-3 levels than small-for-gestational age (SGA) neonates (P < 0.01, 0.001, 0.01, respectively) and higher total IGF-I and IGFBP-3 levels than appropriate-for-gestational age (AGA) neonates (P < 0.05, 0.01, respectively). The free-to-total IGF-I ratios and IGF-II levels were not different among SGA, AGA, and LGA neonates. Free IGF-I, total IGF-I, and IGFBP-3 levels were positively correlated with birth weight (r = 0.34, P < 0.001; r = 0.41, P < 0.001; r = 0.25, P < 0.05, respectively). Multiple linear regression analyses revealed that only total IGF-I levels was the independent predictive variable for birth weight.


CONCLUSIONS
Our data suggest total IGF-I is the most important factor in the IGF system for determining fetal growth, at least near term gestation. Free-to-total IGF-I ratios may mostly be determined by total IGF-I. If birth size is associated with adult chronic metabolic diseases, total IGF-I may be involved in the pathogenesis.
Hung
Te-Yu
TY
Department of Pediatrics, Chi Mei Foundation Medical Center, Tainan County, Taiwan.
Lin
Chin-Chuan
CC
Hwang
Yea-Shwu
YS
Lin
Shio-Jean
SJ
Chou
Yen-Yin
YY
Tsai
Wen-Hui
WH
D001724:Birth Weight; D001827:Body Height; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007335:Insulin-Like Growth Factor II / Q000032:analysis*; D016014:Linear Models
D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II