# Does Vitamin D Concentration Matter? The Consequential Effects of Serum Vitamin D Concentration and Supplementation on Paediatric Fracture Risk

## TL;DR

This study found that lower vitamin D levels in children are linked to a higher risk of fractures, suggesting maintaining adequate vitamin D may help prevent fractures in children.

## Contribution

The study provides new evidence linking suboptimal vitamin D levels to increased fracture risk in a large Southeast Asian pediatric cohort.

## Key findings

- Children with lower serum 25(OH)D concentrations had a higher risk of fractures.
- Sub-sufficient vitamin D status (<30 ng/mL) was more prevalent among children with fractures.
- Vitamin D supplementation was associated with fracture risk, though causality could not be determined.

## Abstract

Objective: The association between vitamin D status and paediatric fracture risk remains controversial, with inconsistent findings across existing studies. This study aimed to evaluate the relationship between serum 25(OH)D concentrations, vitamin D sufficiency, insufficiency and deficiency, vitamin D supplementation and fracture risk in a large Southeast Asian paediatric cohort. Methods: This retrospective cross-sectional study included children under 18 years whose serum 25(OH)D concentrations were measured between 2014 and 2022. One-way ANOVA determined statistical significance between 25(OH)D concentrations in fracture and non-fracture groups. Prevalence of vitamin D insufficiency, deficiency and supplementation was compared between the two groups. Chi-square tests evaluated the association between 25(OH)D concentrations and supplementation against fracture risk. Results: A total of 4530 children were included (157 fracture cases, 4373 controls). Mean serum 25(OH)D concentration was lower in the fracture group than in the controls (27.44 ± 12.26 vs. 30.75 ± 15.21 ng/mL; p = 0.007). Sub-sufficient vitamin D status (<30 ng/mL) was more prevalent among fracture patients (p = 0.001), and suboptimal (p = 0.001), insufficient (p = 0.001), and deficient (p = 0.014) categories were each significantly associated with fractures. An association between vitamin D supplementation and fracture risk was observed. However, the dataset did not permit the determination of causality and a protective effect cannot be inferred. Conclusions: Higher serum 25(OH)D concentrations were associated with lower fracture risk, suggesting that optimisation of vitamin D status may represent a modifiable factor in paediatric bone health. Healthcare institutions should aim to maintain adequate 25(OH)D concentrations (>30 ng/mL). An association between vitamin D supplementation and fracture risk was observed; however, causality cannot be inferred from this retrospective dataset.