Despite previous reports, vitamin D levels are not linked to asthma, atopic dermatitis, or allergies according to a new Canadian study.
Researchers from McGill University and the Lady Davis Institute at the Jewish General Hospital, both in Montreal, looked at genetic and health data on more than 100,000 participants from previous large-scale studies.
They were trying 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.
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. 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 were linked to an increased risk for other inflammatory diseases. They also found evidence for a causal link between low vitamin D and multiple sclerosis, a common neurological disorder more common in white people of European descent and women.
The researchers concluded increasing levels of vitamin D is unlikely to result in a reduced risk of asthma or dermatitis in adults and children.
Lead author Dr. Despoina Manousaki, added: "Our findings suggest that previous associations between low vitamin D and atopic disease could be due to spurious associations with other factors."
The findings have been published in PLOS Medicine.
