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Vitamin D unlikely to lower risk of asthma, atopic dermatitis

Increasing vitamin D is unlikely to reduce the risk of pediatric and adult asthma, atopic dermatitis or other allergies, according to study results recently published in PLOS Medicine

“Our findings suggest the previous associations between low vitamin D and atopic disease could be due to spurious associations with other factors,” researcher Despoina Manousaki, MD, a PhD student at Lady Davis Institute for Medical Research, McGill University, Montreal, stated in a press release. “Efforts to increase vitamin D levels will probably not result in decreased risk of adult and pediatric asthma, atopic dermatitis [AD], or elevated igE levels.”

Manousaki and colleagues used data from large-scale studies of people of European descent to test whether genetically lowered vitamin D levels were associated with the risk of asthma in children and adults, AD or elevated serum IgE levels.

The researchers conducted Mendelian randomization methodology studies by using four single-nucleotide polymorphisms strongly associated with 25-hydroxyvitamin D (25OHD) levels in 33,996 individuals to estimate the effects of lowered 25OHD on the risk of asthma (n = 146,761), childhood-onset asthma (n = 15,008), AD (40,835) and elevated igE level (n = 12,853).

There were no associations between the four 25OHD-lowering alleles with asthma, AD or elevated IgE levels (P ≥ .02).

“The [Mendelian randomization] ratio per standard deviation decrease in log-transformed 25OHD was 1.03 (95% CI, 0.90-1.19) for asthma, 0.95 (95% CI, 0.69-1.31) for childhood-onset asthma and 1.12 (95% CI, 0.92-1.37) for AD, and the effect size on log transformed igE levels was -0.40 (95% CI, -1.65 to 0.85),” the researchers wrote.

When sensitivity analyses were conducted, the results were similar.

“In conclusion, our [Mendelian randomization] study provides no support for an unconfounded relationship between 25OHD levels and risk of atopic disease in individuals of European descent,” the researchers concluded. “Instead, association of 25OHD levels with atopic disease in the general population is more likely to be attributable to confounding by lifestyle factors such as obesity and physical inactivity.”– by Bruce Thiel

Disclosure: The researchers report no relevant financial disclosures.