Researchers have found that vitamin D deficiency does not contribute to the frequency or severity of pediatric asthma. And vitamin D supplementation doesn’t alleviate its symptoms.

Because many people with asthma are vitamin D deficient, scientists have long hypothesized that the deficiency had a causative effect on asthma by regulating airway reactivity, causing sensitivity to corticosteroids or modulating immune function.

However, using a Mendelian randomization approach, Erik Hysinger, MD, MS, of our Division of Pulmonary Medicine, and a team of scientists proved otherwise.

Hysinger was first author on the study, which was conducted while he was a fellow at the Children’s Hospital of Philadelphia and published on December 31, 2016, in the Journal of Allergy and Clinical Immunology.

They undertook the study because there had long been conflicting theories about the relationship between vitamin D and asthma.

The scientists studied 12,842 children with asthma, and their findings showed that asthma predisposes children to low 25(OH)D concentration, not the other way around.

In recent years, researchers have used Mendelian randomization to drill down into the data on causality when association studies show one factor – in this case vitamin D deficiency – could impact modifiable risk factors and disease.

 “It was very exciting to use a novel technique to further investigate and provide new insight into this relationship,” says Hysinger.