The research examined the relationship between 25(OH)D concentrations and neurodevelopmental outcomes in children aged three to five.
Researchers analysed data from a follow-up study of a randomised clinical trial in which women randomly received 400, 2000 or 4000 IU vitamin D3/day for the length of their pregnancy and children took yearly Brigance Testing to assess their development.
The authors conclude: “Higher 25(OH)D at the time of testing was associated with better overall performance on neurodevelopmental testing.”
Conflicting evidence on vitamin D
The authors outline the “discrepancy” in current literature on vitamin D’s role in cognition and neurodevelopment.
For example, one recent review highlighted growing evidence vitamin D deficiency during pregnancy puts offspring at increased risk of neurological disorders. Several studies found relationships between lower 25(OH)D concentrations and increased risk of autism spectrum disorders in children. Maternal vitamin D during pregnancy has also been linked to autism spectrum disorder in children.
However, another report suggests vitamin D supplementation with 2800 IU/day during pregnancy isn’t associated with differences in child neurodevelopment. While some research shows higher cord blood vitamin D status was linked to better problem-solving abilities, other reports contradict this.
The vitamin D binding protein (VDBP) genotype is an important factor in research. Among children who receive the recommended vitamin D daily allowance, those with the Gc1s allele had the highest concentration of circulating 25(OH)D. Conversely, children with the Gc1f allele were more likely to be vitamin D insufficient.
One recently published paper showed associations between VDBP genotype (specifically the Gc1f allele) and worsening severity of autism spectrum disorder – suggesting a link between VDBP genotype and neurodevelopment.
Randomised clinical trial
In the study from which data was analysed, a total of 502 pregnant women enrolled – 350 continued until delivery. Of these women’s children, 156 completed follow-up visits when they were between three and five years old.
The study showed higher 25(OH)D at the time of testing was associated with better overall performance on neurodevelopmental testing.
The authors conclude: “We demonstrate that higher 25(OH)D early in childhood is associated with higher scores on neurodevelopmental testing. We also link higher dose maternal vitamin D supplementation and higher maternal 25(OH)D concentrations during pregnancy with better language development in offspring.”
The authors note that various VDBP genotypes may affect different areas of neurodevelopment in different ways. They point out children with the Gc1f1s or Gc1f2 genotypes have higher academic scores and lower language scores.
They conclude: “Together, these results indicate the importance of ensuring vitamin D sufficiency early in life, provide support for the use of higher doses of vitamin D supplementation during pregnancy, and confirm the need for further studies investigating the potential role of genetics in the relationship between vitamin D status and neurodevelopment.”
Limitations of the study
The authors highlight the limitations of a small sample size and that they didn’t measure other nutrients that could impact neurodevelopment. They also couldn’t measure parental intelligence and didn’t take into account factors like food insecurity, housing and potential environmental exposures.
"Vitamin D and Child Neurodevelopment—A Post Hoc Analysis."
Authors: Rodgers, M.D.; Mead, M.J.; McWhorter, C.A.; Ebeling, M.D.; Shary, J.R.; Newton, D.A.; Baatz, J.E.; Gregoski, M.J.; Hollis, B.W.; Wagner, C.L. 2023, 15, 4250.