Body height in paediatric inflammatory bowel diseases: A structural equation model analysis.

BACKGROUND: Linear growth restriction is a unique feature of paediatric inflammatory bowel diseases (IBD), and reduced insulin-like growth factor (IGF-1) is a major determinant of short stature. We aimed to assess factors influencing somatic height in children suffering from IBD.

MATERIALS AND METHODS: This was a retrospective, cross-sectional study conducted after approval by Institutional authorities. Anthropometric data, disease-related factors, biochemical and clinical indices of inflammation and endocrine parameters were recorded and considered as explanatory covariates. A structural equation model analysis was utilized. Somatic height was the outcome of interest, and possible associations of explanatory covariates directly or through the mediation effect of IGF-1 were assessed.

RESULTS: Systemic inflammation, as expressed by high-sensitivity intereukin-6 (IL-6), and nutritional status described by body mass index (BMI) were the pathways that significantly affected stature through the mediation effect of IGF-1. Cortisol showed a direct, positive and independent of IGF-1 association with height.

CONCLUSIONS: Insulin-like growth factor-1 is a key player in the process that results in impaired linear growth. Malnutrition and systemic inflammation have a restrictive action on growth by reducing circulating IGF-1. The positive relation of serum cortisol to height could correspond to suppressed pituitary-adrenal axis due to long-term use of glucocorticoids.