Effects of Vitamin D Supplementation on Children with Autism Spectrum Disorder: A Systematic Review and Meta-analysis

Area of Science:

• Pediatric Neurology
• Nutritional Psychiatry
• Autism Spectrum Disorder Research

Background:

• Autism spectrum disorder (ASD) is a complex neurodevelopmental condition.
• The role of vitamin D in ASD is under investigation, with existing evidence being inconclusive.
• Core symptoms of ASD include social communication deficits and restricted, repetitive behaviors.

Purpose of the Study:

• To conduct a meta-analysis of randomized controlled trials (RCTs) evaluating vitamin D supplementation in children with ASD.
• To determine if vitamin D improves core ASD symptoms and associated coexisting conditions.
• To synthesize current evidence on vitamin D's efficacy in managing ASD manifestations.

Main Methods:

• Systematic literature search of PubMed, Embase, Web of Science, CINAHL, and Cochrane Library databases up to February 2022.
• Inclusion of eight RCTs involving 266 children with ASD.
• Meta-analysis using a random-effects model to calculate pooled mean differences and 95% confidence intervals (CIs).

Main Results:

• Vitamin D supplementation significantly improved stereotypical behavior scores (MD: -1.39; 95% CI: -2.7, -0.07; P = 0.04) with low heterogeneity (I² = 34%).
• A trend towards decreased scores on the Social Responsiveness Scale (SRS) and Childhood Autism Rating Scale (CARS) was observed (P = 0.05).
• No significant differences were found in other core ASD symptoms or coexisting conditions as measured by the Aberrant Behavior Checklist (ABC).

Conclusions:

• Vitamin D supplementation may be beneficial for reducing stereotypical behaviors in children with ASD.
• Current evidence does not support vitamin D's efficacy for other core ASD symptoms or coexisting conditions.
• Further large-scale RCTs with individualized dosing are necessary to confirm these findings and explore optimal therapeutic strategies.