Early life vitamin D status

: implications for child neurodevelopment

Abstract

Vitamin D has been shown to play an essential role during pregnancy for maternal and child health. Whilst a vitamin D status of >75 nmol/L is needed for optimal musculoskeletal health, a status of >100 nmol/L has been suggested for non-skeletal functions including neurodevelopment. The main source of vitamin D is via sun exposure, and it can be obtained from limited dietary sources including fish. The overall aim of this thesis was to examine associations between early life vitamin D status and child neurodevelopmental outcomes.

A systematic review and meta-analysis investigated associations between prenatal and neonatal vitamin D status and child diagnosis of autism spectrum disorder (ASD) and highlighted that vitamin D deficiency during early pregnancy may be a risk factor for ASD diagnosis.

Associations between vitamin D status of maternal and cord samples in an equatorial (Seychelles, 4°S), high fish-eating population, and in school children in a high latitude country (Northern Ireland 55°N), with child neurodevelopment outcomes were examined. Overall, trends from these three studies suggest that a vitamin D status of >75 nmol/L is beneficial for child neurodevelopment.

The effects of fish consumption on the vitamin D status of women of childbearing age in Northern Ireland during winter was assessed. Results showed that 1-2 portions of fish were not effective at increasing or maintaining vitamin D status during winter compared to no fish consumption in a vitamin D insufficient population.

Overall, this thesis demonstrates the importance of vitamin D during early life for neurodevelopmental outcomes in children. It adds to the current evidence that a status of >75 nmol/L is optimal for beneficial neurodevelopment outcomes, and that fish consumption should be supplemented with safe sun exposure and supplement use to achieve an adequate status. Future studies are required to confirm the optimal vitamin D status at the optimal time during early life for extra-skeletal outcomes such as neurodevelopment.

Date of Award	2022
Original language	English
Sponsors	Department for the Economy, United States National Institute of Environmental Health Sciences & Government of the Republic of the Seychelles
Supervisor	Maria Mulhern (Supervisor), Emeir Mc Sorley (Supervisor), Alison Yeates (Supervisor), Sean Strain (Supervisor) & Stephen Gallagher (Supervisor)