Vitamin D levels not linked to asthma or dermatitis
10 May 2017
In a new study conducted by an international group of organisations including the MRC IEU has discovered that taking Vitamin D supplements is unlikely to reduce the risk of asthma in children or adults, atopic dermatitis, or allergies.
Previous studies in this area have suggested that low vitamin D levels are associated with increased rates of asthma, atopic dermatitis—an itchy inflammation of the skin—and elevated levels of IgE, an immune molecule linked to atopic disease (allergies).
To test the validity of this the team ran a study to see whether genetically lowered vitamin D levels were associated with risk of asthma, atopic dermatitis or serum IgE levels. It used Genome Wide Analysis Study (GWAS) data from over 100,000 participants and used Mendelian randomization (MR) analysis to determine the causal relationship.
They were able to discover that there was little evidence for a difference between rates of asthma (including childhood-onset asthma), atopic dermatitis, or IgE levels in people with and without any of the four genetic changes associated with lower levels of 25-hydroxyvitamin D.
Dr Lavinia Paternoster of the MRC IEU says "This study found that vitamin D does not have a large effect on risk of atopic disease, suggesting that any efforts to increase vitamin D clinically would have little effect on these conditions. It was made possible through the sharing of GWAS summary statistics from a number of research groups worldwide enabling this important question to be addressed in a well-powered analysis of >100,000 individuals."
You can read the study in full in PLOS Medicine here: http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002294