title: Effects of gender, body composition and birth size on IGF-I in 7- and 8-year-old children.
abstract: We investigated the relationship between IGF-I, gender, height, weight, body composition and birth size in 260 healthy 7- and 8-year-old children (139 females). All children were born term at Nepean Hospital, Western Sydney. Body composition was measured using dual energy X-ray absorptiometry. IGF-I levels were determined by radioimmunoassay. Girls had higher IGF-I levels than boys (20.2 +/- 6.5 nmol/l compared to 15.9 +/- 6.1 nmol/l, p < 0.001) but there was no correlation between age and IGF-I. IGF-I was positively correlated with height SDS (R(2) = 0.12), weight SDS (R(2) = 0.19), BMI SDS (R(2) = 0.18), total body fat (%) (R(2) = 0.14), and fat-free tissue/cm (R(2) = 0.03). After adjusting for gender and current weight, IGF-I-levels were inversely related to birth size - children with the lowest birth size and heaviest current weight had the highest IGF-I levels. This correlation between birth weight and IGF-I supports the hypothesis that the IGF-I axis is altered in babies who are small for gestational age.
authors.affiliation: Robert Vines Growth Centre, Ray Williams Institute of Endocrinology, Diabetes and Metabolism, Royal Alexandra Hospital for Children, Sydney, Australia. sarahg@nch.edu.au
authors.forename: S
authors.initials: S
authors.lastname: Garnett
authors.forename: C T
authors.initials: CT
authors.lastname: Cowell
authors.forename: D
authors.initials: D
authors.lastname: Bradford
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: C
authors.initials: C
authors.lastname: Tao
authors.forename: V
authors.initials: V
authors.lastname: Petrauskas
authors.forename: R
authors.initials: R
authors.lastname: Fay
authors.forename: L A
authors.initials: LA
authors.lastname: Baur
mesh_terms: D001724:Birth Weight; D001823:Body Composition; D001827:Body Height; D001835:Body Weight; D002648:Child; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D012727:Sex Characteristics
chemical_list: D007334:Insulin-Like Growth Factor I