According to the World Health Organization (WHO), asthma is the most common chronic disease among children, globally. An inflammatory respiratory disease that causes breathlessness, coughing and wheezing, asthma has an approximate 10% prevalence in children aged 6-7 across the world. Adult onset asthma also occurs.
There may be a relationship between childhood onset asthma and neonatal vitamin D (25(OH)D3) status. Maternally derived vitamin D via the placenta is the only form available to the fetus. There is some evidence that low gestational vitamin D can influence the offspring’s lung and immune functions, contributing to childhood asthma development. There is mixed evidence regarding whether maternal vitamin D supplementation can reduce the risk of childhood onset asthma.
A new study led by Berit Lilienthal Heitmann of The Parker Institute, Frederiksberg, Denmark, examined the influence of neonatal vitamin D status on the development of asthma among children aged 3–9 years using the Danish National Patient Register (DNPR). The results were published in the journal Nutrients.
Vitamin D status of the newborn was assessed by dried blood spot analysis. This revealed that the hazard ratio for developing asthma between age 3–9 years was lower for children with vitamin D levels of 44–111 nmol/L (0.55, 95% CI: 0.39–0.77) than for children with <12 nmol/L at birth.
A potentially serious limitation of the study was that the vitamin D concentrations measured from the dried blood spots were unexpectedly low compared to other studies. Quintiles were used instead of standard medically recognized cut-offs for vitamin D. This raises the possibility that the blood spots were degraded. If they did not degrade uniformly this could invalidate the cross sample comparisons.
“Results from our study show a lower risk of developing asthma among children age 3–9 years within the highest quintile of neonatal 25(OH)D3 concentration, suggesting that vitamin D status is important for normal immune- and lung development. Same associations were observed among girls and boys, and among children born in both seasons,” concluded the authors.