Moreira-Andrés MN, Papapietro K, Cañizo FJ, Rejas J, Larrodera L, Hawkins FG. Correlations between bone mineral density, insulin-like growth factor I and auxological variables. Eur J Endocrinol 1995; 132:573–9. ISSN 0804–4643
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.
MN Moreira-Andrés, Servicio de Endocrinología, Hospital 12 de Octubre, Carretera de Andalucia km. 5,4, 28041 Madrid, Spain
Characterization of a novel alternatively-spliced 5′ exon in the human insulin-like growth factor I (IGF-I) gene, expressed in liver and some cancers