CONTEXT: Many aspects of hormonal regulation and mechanisms of normal infancy growth are poorly understood. OBJECTIVE: The objective of this study was to establish the determinants of serum growth factor levels in infancy and their association with growth. DESIGN: A prospective, longitudinal, population-based birth cohort between 1997-2001 was studied. PARTICIPANTS: Study participants were 942 healthy appropriate weight for gestational age (AGA) infants (538 boys and 404 girls) and 49 small for gestational age (SGA) children (29 boys and 20 girls). INTERVENTIONS: INTERVENTIONS were anthropometrical measurements (0, 3, 18, and 36 months) and serum samples (3 months). MAIN OUTCOME MEASURES: Height, weight, and serum IGF-I and IGF-binding protein-3 (IGFBP-3) were the main outcome measures. RESULTS: IGF-I levels showed no gender difference [boys, 92 ng/ml (confidence interval, 49, 162); girls, 91 ng/ml (47, 149); P = 0.50]. IGFBP-3 levels were significantly higher in females [2174 ng/ml (1295, 3330)] than in males [2103 ng/ml (1266, 3143); P = 0.04]. Infants receiving breast milk had lower IGF-I levels [90 ng/ml (48, 154)] than infants receiving formula [n = 62; 97 ng/ml (58, 165)] or both [n = 123; 94 ng/ml (48, 169); P < 0.001]. IGF-I and IGFBP-3 levels were positively associated with weight gain and height gain from birth to 3 months of age in AGA, but not in SGA, children. SGA children had significantly lower IGF-I [88.0 ng/ml (28, 145); P = 0.05] and IGFBP-3 [1835 ng/ml (1180, 2793); P < 0.001] levels than AGA children. CONCLUSION: We found a significant, but weak, association between IGF-I and IGFBP-3 levels at 3 months and postnatal growth in AGA, but not SGA, children. Factors other than IGF-I must contribute to the regulation of normal postnatal growth, and these may differ between AGA and SGA children. IGFBP-3, but not IGF-I, showed a gender difference, which may reflect an influence of the postnatal activation of the pituitary-gonadal axis on binding protein levels.
CONTEXT: Many aspects of hormonal regulation and mechanisms of normal infancy growth are poorly understood. OBJECTIVE: The objective of this study was to establish the determinants of serum growth factor levels in infancy and their association with growth. DESIGN: A prospective, longitudinal, population-based birth cohort between 1997-2001 was studied. PARTICIPANTS: Study participants were 942 healthy appropriate weight for gestational age (AGA) infants (538 boys and 404 girls) and 49 small for gestational age (SGA) children (29 boys and 20 girls). INTERVENTIONS: INTERVENTIONS were anthropometrical measurements (0, 3, 18, and 36 months) and serum samples (3 months). MAIN OUTCOME MEASURES: Height, weight, and serum IGF-I and IGF-binding protein-3 (IGFBP-3) were the main outcome measures. RESULTS:IGF-I levels showed no gender difference [boys, 92 ng/ml (confidence interval, 49, 162); girls, 91 ng/ml (47, 149); P = 0.50]. IGFBP-3 levels were significantly higher in females [2174 ng/ml (1295, 3330)] than in males [2103 ng/ml (1266, 3143); P = 0.04]. Infants receiving breast milk had lower IGF-I levels [90 ng/ml (48, 154)] than infants receiving formula [n = 62; 97 ng/ml (58, 165)] or both [n = 123; 94 ng/ml (48, 169); P < 0.001]. IGF-I and IGFBP-3 levels were positively associated with weight gain and height gain from birth to 3 months of age in AGA, but not in SGA, children. SGA children had significantly lower IGF-I [88.0 ng/ml (28, 145); P = 0.05] and IGFBP-3 [1835 ng/ml (1180, 2793); P < 0.001] levels than AGA children. CONCLUSION: We found a significant, but weak, association between IGF-I and IGFBP-3 levels at 3 months and postnatal growth in AGA, but not SGA, children. Factors other than IGF-I must contribute to the regulation of normal postnatal growth, and these may differ between AGA and SGA children. IGFBP-3, but not IGF-I, showed a gender difference, which may reflect an influence of the postnatal activation of the pituitary-gonadal axis on binding protein levels.
Authors: Malene Boas; Hanne Frederiksen; Ulla Feldt-Rasmussen; Niels E Skakkebæk; Laszlo Hegedüs; Linda Hilsted; Anders Juul; Katharina M Main Journal: Environ Health Perspect Date: 2010-07-09 Impact factor: 9.031
Authors: M Inés Klein; Eduardo Bergel; Luz Gibbons; Silvina Coviello; Gabriela Bauer; Alicia Benitez; M Elina Serra; M Florencia Delgado; Guillermina A Melendi; Susana Rodríguez; Steven R Kleeberger; Fernando P Polack Journal: Pediatrics Date: 2008-06 Impact factor: 7.124
Authors: Francis de Zegher; Giorgia Sebastiani; Marta Diaz; David Sánchez-Infantes; Abel Lopez-Bermejo; Lourdes Ibáñez Journal: Diabetes Date: 2012-05-29 Impact factor: 9.337