Vitamin D level, body mass index and fracture risk in children: vitamin D deficiency and fracture risk

J Pediatr Orthop B. 2021 Mar 18. doi: 10.1097/BPB.0000000000000867. Online ahead of print.


Objective: To determine the impacts of preventable causes of fracture, such as vitamin D deficiency, disturbed calcium homeostasis and obesity on fracture occurrence in minor traumas. In this way, the effects of relevant parameters on fracture may be further elucidated.

Methods: A prospective case-control study in children aged 2-18 years children with and without fractures was performed. Participants with a pediatric trauma score higher than 10 presenting to minor trauma were included to exclude the significant impact of severe trauma on fracture. The effects of obesity, parameters associated with vitamin D and Ca homeostasis on fracture occurrence were evaluated. Univariate and multivariate analyses were used to test for associations between fracture status and the assessed variables. The relationships between the variables and the odds of fracture occurrence were examined using logistic regression models.

Results: The sample consisted of 76 patients and 50 controls. There were no significant differences between the patients and controls in terms of age, sex, trauma type and pubertal period. The patients had a significantly higher mean BMI percentile (61.2 ± 30.7, 36.7 ± 30.7; P < 0.001). Likewise, patients were more likely than controls to have a lower mean 25(OH)D level and mean phosphorus level (respectively, 13.4 ± 7.0, 17.3 ± 7.8; P = 0.004, and 4.6 ± 0.7, 5.1 ± 0.8; P < 0.001). Moreover, fractures were substantially more frequent in children with vitamin D deficiency (<20 ng/mL, χ2: 7.781, df: 1, P = 0.005). In the multivariate logistic model, BMI percentile and vitamin D levels remained significantly associated with increased odds of fracture [1.02 (1.01-1.04), P < 0.001 and 0.93 (0.89-0.98), P = 0.01].

Conclusions: The present study supports an association of high BMI and vitamin D deficiency with an increased odds of fracture occurrence in children. The findings may help physicians to reduce the risk factors of fracture by preventive efforts. Thus, unexpected health costs and morbidity may be minimized.