Vitamin D and Child Neurodevelopment—A Post Hoc Analysis

Introduction: Vitamin D (VitD) has been shown to impact neurodevelopment. Studies have shown that higher 25-hydroxy-vitamin D (25(OH)D) concentrations (the indicator of vitD status) may be associated with better neurodevelopmental outcomes, although current data are conflicting. This study examined the relationship between total circulating 25(OH)D concentrations and neurodevelopmental outcomes in 3–5-year-old (3–5 yo) children. Methods: In this study, pregnant women were randomized to receive 400 (standard dose), 2000, or 4000 IU vitD(3)/day. Offspring then underwent the Brigance Screen at 3–5 yo. The 25(OH)D concentration was measured at birth and 3–5 yo. Relationships between Brigance scores and 25(OH)D and Brigance scores and vitamin D binding protein (VDBP) genotype were examined. Results: Higher 25(OH)D at the time of testing was associated with better overall performance on neurodevelopmental testing as measured by the Brigance quotient (B = 0.208, p = 0.049). Scores were then broken down into sub-scores. Children born to mothers in the 2000 IU/day group scored higher on the Brigance language component of the assessment versus the standard dose group (B = 4.667, p = 0.044). The group of children who had the Gc1f-1s or Gc1f-2 genotypes scored higher on the Brigance academic component (B = 9.993, p < 0.001) and lower on the Brigance language component versus the 1f1f genotype (B = −9.313, p < 0.001). Children with the Gc1s-1s, Gc1s-2, or Gc2-2 genotypes also scored lower than the Gc1f-1f genotype (B = −6.757, p = 0.003). Conclusion: These results suggest that higher 25(OH)D concentrations early in life and higher doses of maternal vitamin D supplementation during pregnancy may have a positive association with neurodevelopmental outcomes. This study also suggests that the VDBP genotype is associated with neurodevelopment and differentially affects various fields of neurodevelopment.