Vitamin D level and fractures in children and adolescents: a systematic review and meta-analysis.

INTRODUCTION: The aim of the study was to determine the relationship between vitamin D levels and the risk of bone fractures in children and adolescents. MATERIALS AND METHODS: PubMed, Embase, and Cochrane library databases were searched using subject and free words. The Newcastle-Ottawa scale form was used to assess literature quality. ReVman 5.2 and Stata 13.0 were used for statistical analyses. The results were expressed as the mean difference (MD)/odds ratio (OR) and 95% confidence interval (95% CI). The heterogeneity test was conducted according to I2 and Q tests. Egger's test was used to evaluate publication bias. RESULTS: Thirteen studies (3943 participants ≤ 18 years old) were included, and the quality of the literature was acceptable. Regarding the 25-hydroxyvitamin D (25OHD) level in the random effects model, the MD = - 0.12 ng/mL (95% CI: -1.93, 1.69), I2 = 83%, and P < 0.00001, indicating large heterogeneity. Subgroup analyses were conducted according to vitamin D supplementation and 25OHD level, the sources of heterogeneity were not found. Regarding the proportion of subjects with vitamin D deficiency in the random effects model, OR = 1.09 (95% CI: 0.67, 1.79), I2 = 79%, and P < 0.0001. By sensitivity analysis, after removing Al-Daghri's study, OR = 1.22 (95% CI: 0.96, 1.56), I2 = 0%, and P = 0.64. CONCLUSION: There is no relationship between vitamin D level and the risk of bone fractures in children and adolescents.