The impact of age, disease severity, and BMI on bone health and growth in children and young people with Crohn's disease.

ABSTRACT

Objectives: The objective of this study was to explore the correlation between paediatric Crohn's disease (CD) characteristics, bone health and growth parameters at diagnosis and follow-up. Methods: Retrospective data was collected for 47 children aged 4-16 who were newly diagnosed with CD between January 2018 and December 2019. Mean follow-up time was 2.5 years. Results: Eleven (24%) children had growth delay at diagnosis, which persisted in 4 (44%) of 9 recorded children at follow-up. Of the 35 children tested, 20 (57%) had inadequate Vitamin D levels (<50 mmol/L) at diagnosis. Thirty-seven (79%) children had a dual-energy X-ray absorptiometry scan at diagnosis, with 20 of them having at least 1 low Z-score. Children with poorer bone mineral density and bone mineral concentration Z-scores for age had a younger age at diagnosis (p = .042 and p = .021), more severe disease (p = .04 and p = .029) and a lower BMI (p < .001) at diagnosis. Children diagnosed with CD ≥11 years had a lower-than-expected height velocity (p < .0001 and p < .001). Multivariate regression analysis demonstrated an older age of diagnosis was a significant predictor of a lower height velocity at follow-up. Conclusion: Disease severity and age of diagnosis are important CD-related factors that influence bone health and growth. Vitamin D is an accessible component that if optimised can improve all three factors. Monitoring and optimising each aspect systematically has the potential to enable children to achieve their bone health and growth potentials.