title: Correlations between bone mineral density, insulin-like growth factor I and auxological variables.
abstract: Recent studies have shown growth-related changes in spinal bone mineral density (BMD) in children; however, there is less information available on the relationship between BMD and insulin-like growth factor I (IGF-I). The aim of this study was to relate the BMD of the spine and radius with serum IGF-I levels and auxological variables in normally growing children. We used dual X-ray absorptiometry to measure the BMD in the lumbar spine (L1-L4) and distal radius of 121 children (69 boys, 52 girls) aged 3-18 years whose growth velocity was normal. Lumbar and radial BMD increased with age (p < 0.001) and puberty (p < 0.001) and was highly correlated to age, weight, height, body surface and bone age (r = 0.70-0.89 and p < 0.001 for all variables). Partial correlation, with age held constant, was weaker but still significant for most auxological variables. Serum IGF-I concentrations increased slowly during childhood and markedly during early stages of puberty, and correlated with lumbar and radial BMD (r = 0.55 and 0.45, respectively; p < 0.001) and with the auxological variables (p < 0.001). When age was held constant, IGF-I levels still correlated significantly with the auxological variables and with BMD, except in the case of radial BMD in boys. By multiple regression analysis IGF-I, unlike auxological variables, did not reach significance in the ability to predict BMD. Therefore, in healthy children, serum IGF-I levels show a weaker relationship to BMD than do auxological variables.
authors.affiliation: Servicios de Endocrinología and Bioquimica, Hospital Universitario 12 de Octubre, Madrid, Spain.
authors.forename: M N
authors.initials: MN
authors.lastname: Moreira-Andrés
authors.forename: K
authors.initials: K
authors.lastname: Papapietro
authors.forename: F J
authors.initials: FJ
authors.lastname: Cañizo
authors.forename: J
authors.initials: J
authors.lastname: Rejas
authors.forename: L
authors.initials: L
authors.lastname: Larrodera
authors.forename: F G
authors.initials: FG
authors.lastname: Hawkins
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000375:Aging / Q000502:physiology; D001827:Body Height; D001835:Body Weight; D015519:Bone Density; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D011627:Puberty / Q000502:physiology; D011884:Radius; D013131:Spine
chemical_list: D007334:Insulin-Like Growth Factor I