Vitamin D deficiency can exacerbate asthmatic symptoms in children, says a new study.
They study led by Dr Juan Celedon, Dr. P.H. and Dr Augusto Litonjua, of Harvard Medical School has shown that children with lower vitamin D levels were significantly more likely to have been hospitalized for asthma, tended to have airways with increased hyperreactivity and were likely to have used more inhaled corticosteroids, all signifying higher asthma severity.
These children were also significantly more likely to have several markers of allergy, including dust-mite sensitivity.
"To our knowledge this is the first study to demonstrate an inverse association between circulating levels of vitamin D and markers of asthma severity and allergy," said researchers.
"While it is difficult to establish causation in a cross-sectional study such as this, the results were robust even after controlling for markers of baseline asthma severity," they added.
"This study suggests that there may be added health benefits to vitamin D supplementation," said Dr. Celedon.
The study showed that serum levels of vitamin D in more than 600 Costa Rican children were inversely linked to several indicators of allergy and asthma severity,
Current recommendations for optimal vitamin D levels geared toward preserving bone health, such as preventing rickets in children and osteoporosis in adults.
"This study also provides epidemiological support for a growing body of in vitro evidence that vitamin D insufficiency may worsen asthma severity, and we suspect that giving vitamin D supplements to asthma patients who are deficient may help with their asthma control" wrote the researchers.
However, whether vitamin D supplementation can prevent the development of asthma in very young children is a separate question and requires further investigation, they said.
The study appears in American Journal of Respiratory and Critical Care Medicine.