A child develops rapidly within the first few years of life. These early years are extremely important for developing motor function, communication, behavioral skills, neurocognitive function and more.
Some research has linked neurocognitive development and hyperactivity disorders to maternal intake of vitamin D. A recent study found that vitamin D supplementation significantly improved cognitive function in adolescents. Researchers has also found associations between vitamin D deficiency and cognitive improvements in the elderly. However, the few observational studies that have studied the relationship between vitamin D status and neurocognitive development in the early years of a child’s life have been inconsistent. Therefore, researchers examined the role of maternal vitamin D status on cognitive and behavioral development in children aged 6 months to 9 years old.
Pregnant women from Avon in southwestern England were recruited for this study. Researchers included a total of 7,065 mother and infant pairs in this study. Researchers included women who had available vitamin D levels during pregnancy and a child that displayed at least one neurodevelopmental outcome between the ages of 6 months and 9 years. Researchers evaluated outcomes such as motor development, communication, social skills, behavior, cognition and reading ability.
The Avon Longitudinal Study of Parents and Children (ALSPC) preschool developmental test was administered to the mothers of all children between six and 42 months of age. This questionnaire measured four developmental categories: fine motor skills, gross motor skills, communication and social skills. The Strengths and Difficulties Questionnaire (SDQ), which addressed behavioral development, was administered to the mothers when the child was 81 months of age. Intelligence quotient (IQ) was measured when the children were 8 years old, and their reading skills were analyzed at 9 years. In addition, vitamin D deficiency was defined as <10 ng/ml, insufficiency as between 11-19 ng/ml and sufficiency as >20 ng/ml.
This is what the researchers discovered:
- A total of 21.6% of the women had their vitamin D levels measured during the first trimester, 11.8% in the second trimester and 62.3% in the third trimester.
- Average vitamin D level in the first trimester was 21.9 ng/ml, 23.7 ng/ml in the second trimester and 26.1 ng/ml in the third trimester.
- Vitamin D levels above 20 ng/ml were associated with scores indicating better fine and gross motor skills at 30 months (p=0.008 and p=0.01, respectively) and social development at 42 months (p=0.02) when compared with lower levels.
- After adjusting for fatty fish intake, there was a significant association between maternal vitamin D status and gross motor development at 18 months (p=0.02).
- When comparing sufficient to deficient vitamin D levels, these outcomes were more closely associated with the second half of pregnancy than the first half (>22 weeks; p<0.05).
The researchers concluded:
“We found that maternal vitamin D status in pregnancy was associated with a number of adverse neurocognitive developmental variables in early childhood, albeit with a small, but nonetheless important, effect size.”
While this study had strengths, such as its large sample population, a few limitations should be addressed. First, vitamin D status was only measured once during pregnancy. Measuring vitamin D status at several points during the pregnancy and while breastfeeding would have resulted in a better indication of vitamin D levels over time. Also, the researchers noted that the majority of participants were caucasian. Increasing the diversity of a study population may have altered the findings. Last, the vitamin D status of the children were not measured. Comparing the children’s vitamin D status to neurodevelopmental function could have altered the findings , especially as the children aged and vitamin D levels became independent of the mother’s status.
Maternal vitamin D status is important for infants, as vitamin D levels during pregnancy determine the infant’s level. If women are at a optimal vitamin D status, breastfeeding is the primary supply of vitamin D during the early stages of life. However, as children are weaned off of breast milk, maternal vitamin D status no longer affects the child’s status. It would be interesting to see if maternal vitamin D status during pregnancy or vitamin D status of a developing child has a greater effect on neurodevelopmental outcomes.
Peterson, R. & Cannell, JJ. Maternal vitamin D status is associated with neurodevelopmental outcomes in a child’s first four years of life, 7/2017.
Darling, A. et al. Association between maternal vitamin D status in pregnancy and neurodevelopmental outcomes in childhood: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). British Journal of Nutrition, 2017.