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Correlations between bone mineral density, insulin-like growth factor I and auxological variables
M N Moreira-Andrés1, K Papapietro, F J Cañizo
1Servicios de Endocrinología and Bioquimica, Hospital Universitario 12 de Octubre, Madrid, Spain.
Insights
In healthy children, auxological variables like age and weight are more closely linked to bone mineral density (BMD) than insulin-like growth factor I (IGF-I) levels.
Area of Science:
- Pediatric Endocrinology
- Bone Metabolism
- Growth and Development
Background:
- Childhood bone mineral density (BMD) changes with growth.
- Limited data exists on the relationship between BMD and insulin-like growth factor I (IGF-I) in children.
Purpose of the Study:
- To investigate the correlation between spinal and radial BMD and serum IGF-I levels.
- To compare the relationship of BMD with IGF-I and auxological variables in healthy, normally growing children.
Main Methods:
- Dual X-ray absorptiometry used to measure BMD in the lumbar spine and distal radius.
- Study included 121 children (ages 3-18) with normal growth velocity.
- Serum IGF-I levels and auxological variables (age, weight, height, body surface, bone age) were analyzed.
Main Results:
- BMD of the spine and radius significantly increased with age and puberty.
- BMD strongly correlated with age, weight, height, body surface, and bone age.
- Serum IGF-I levels correlated with BMD and auxological variables, but less strongly than auxological variables themselves.
Conclusions:
- Auxological variables demonstrate a stronger relationship with BMD in healthy children than serum IGF-I levels.
- IGF-I did not significantly predict BMD in multiple regression analysis when auxological variables were considered.
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.