The effect of vitamin D supplementation in treatment of children with autism spectrum disorder: a systematic review and meta-analysis of randomized controlled trials
What this study found
Vitamin D supplementation did not improve core autism spectrum disorder symptoms, but it showed a beneficial effect for hyperactivity. Pooled effects were not significant for social interaction (MD -1.54, 95% CI -4.09 to 1.01; p = 0.24), communication (MD -0.05, 95% CI -1.79 to 1.69; p = 0.96), or repetitive and restricted behaviors (MD 0.85, 95% CI -0.33 to 2.02; p = 0.16). Hyperactivity improved modestly (MD -3.20, 95% CI -6.06 to -0.34; p = 0.03). All trials reported vitamin D as well tolerated, with adverse effects that were not serious and were comparable between groups.
- Study & population
- Systematic review and meta-analysis of randomized controlled trials in children younger than 18 years with autism spectrum disorder.
- Intervention
- Active treatment was oral cholecalciferol (vitamin D3).
- Key limitation
- Evidence was limited by a small number of randomized trials and a modest total sample size.
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Open PDFOriginal abstract
ABSTRACT Objective: The effect of vitamin D supplementation on the risk of Autism Spectrum Disorder (ASD) is conflicting. The aim of this study was to estimate the efficacy of vitamin D supplementation on ASD in children. Methods: We conducted a meta-analysis of randomized controlled trials (RCTs) in which vitamin D supplementation was used as a therapy in children with ASD. The PubMed, PsychINFO, Cochrane CENTRAL library, Web of Science, and Cinahl databases were searched from inception to March 20, 2019, for all publications on vitamin D and ASD with no restrictions. Studies involving individuals aged <18 years diagnosed with ASD and with all functional outcomes assessed by measurement scales for ASD were included. Mean differences were pooled, and a meta-analysis was performed using a random-effects model due to differences between the individual RCTs. Results: There were five RCTs with 349 children with ASD in the review, of which three RCTs were included in the meta-analysis. Vitamin D supplementation indicated a small but significant improvement in hyperactivity scores (pooled MD: −3.20; 95% CI: [−6.06, −0.34]) with low heterogeneity (I2 = 10%, p = 0.33), but there were no other statistically significant differences in ASD symptoms between groups as measured by validated scales. Conclusion: Vitamin D supplementation appears to be beneficial for hyperactivity but not for core symptoms or other co-existing behaviors and conditions of ASD. Future RCTs with large sample sizes examining the effect of vitamin D supplementation on ASD among individuals with low serum vitamin D levels at baseline are needed.