Low level of vitamin D does not raise risk of asthma or dermatitis, says research

Low vitamin D levels do not raise the risk of conditions such as asthma or atopic dermatitis, according to a new study by a team of researchers from the McGill University and the Lady Davis Institute at the Jewish General Hospital, both in Montreal, Canada.

The research, led by the university’s Dr Brent Richards, set out to determine whether there was an association between genetically lowered vitamin D levels and an increased risk of asthma, atopic dermatitis and higher levels of total immunoglobulin E (IgE) – which serve to protect against parasitic infections.

The team examined the single nucleotide polymorphisms (SNPs) – the most common form of genetic variation found in people’s DNA – of more than 100,000 people from existing large scale studies surrounding vitamin D.

The researchers looked at the four genetic variations that are associated with low levels of 25-hydroxyvitamin D – a marker of vitamin D deficiency – as well as looking at the possible associations with adult-onset asthma, and analysed the correlations with childhood asthma separately.

They found no significant differences between the incidence of asthma, atopic dermatitis or raise IgE levels among those with the four genetic variants and those without.

Dr Richards commented: "Previous findings suggest that low vitamin D levels increase risk for some inflammatory diseases like multiple sclerosis, but these effects do not translate to other inflammatory diseases like asthma and atopic dermatitis."

Dr Despoina Manousaki, the first author of the study, added: “Our findings suggest that previous associations between low vitamin D and atopic disease could be due to spurious associations with other factors.

“Efforts to increase vitamin D levels will probably not result in decreased risk of adult and pediatric asthma, atopic dermatitis or elevated IgE levels.”

Atopy is a term that refers to a predisposition to allergic diseases including asthma and atopic dermatitis or eczema, and usually presents itself with elevated IgE levels.

You can read the report Vitamin D Levels and Susceptibility to Asthma, Elevated Immunoglobulin E Levels and Atopic Dermatitis: A Mendelian Randomization Study here.