Lack of vitamin D may be a direct cause of multiple sclerosis, a new study has found.
MS, a potentially disabling auto-immune disease that damages nerve fibres, tends to be more prevalent in places that get less sunshine and sunshine triggering a chemical reaction in the skin is the primary source of vitamin D.
While previous studies have suggested an association between lower vitamin D levels and a higher risk of MS, this latest study has demonstrated a genetic correlation that points strongly to a causal link.
Scientists checked the DNA of nearly 34,000 people and identified variants in the genetic code that were closely associated with a vitamin D blood marker.
A comparison between thousands of MS sufferers and healthy individuals found that people whose genetic makeup was associated with a lack of vitamin D were at least twice as likely to have multiple sclerosis.
Writing in the online journal Public Library of Science Medicine, the authors, led by Dr Brent Richards from McGill University in Canada, wrote: “The identification of vitamin D as a causal susceptibility factor for MS may have important public health implications, since vitamin D insufficiency is common, and vitamin D supplementation is both relatively safe and cost-effective.
“The importance of these findings may be magnified in high-latitude countries, which have disproportionately higher rates of MS and also higher rates of vitamin D insufficiency.”
The finding provided “strong evidence in support of a causal role of vitamin D in MS susceptibility”, said the scientists.
They added: “Whether vitamin D sufficiency can delay or prevent multiple sclerosis onset merits further investigation in long-term randomized controlled trials.”