Despite previous reports, Vitamin D supplements are unlikely to reduce the risk of asthma, atopic dermatitis, or allergies according to a new Canadian study.

Carried out by researchers from McGill University, Canada, and the Lady Davis Institute at the Jewish General Hospital, Canada, team looked at genetic and health data on more than 100,000 participants from previous large-scale studies to determine whether genetic changes associated with vitamin D levels lead to a greater chance of developing asthma, atopic dermatitis  (an itchy inflammation of the skin) or high IgE levels (an immune molecule linked to allergies).

Previous research has linked low vitamin D levels to all three of the conditions.

Contrary to these previous results, the new research found no statistically significant differences between people with or without any of the four genetic changes associated with lower levels of vitamin D and rates of asthma (including childhood-onset asthma), atopic dermatitis, or IgE levels.

The team pointed out that the study did have its limitations, including looking only at white populations of European ancestry, and they now recommend further research in non-European populations and those with a vitamin D deficiency.

However, the team's findings from a recent study using the same participants did suggest that low vitamin D levels increase risk for other inflammatory diseases, with evidence for a causal link between low vitamin D levels and multiple sclerosis, a common neurological disorder more common in white people of European descent and women.

These findings suggest those at risk for multiple sclerosis should ensure that they have adequate vitamin D levels, while researchers concluded increasing levels of vitamin D is unlikely to result in a reduced risk of asthma or dermatitis in adults and children, with lead author of the study Dr. Despoina Manousaki, adding that, "Our findings suggest that previous associations between low vitamin D and atopic disease could be due to spurious associations with other factors." 

The findings can be found published in PLOS Medicine.