A LACK of vitamin D may be a direct cause of Multiple Sclerosis (MS), a new study has claimed.

Scotland has one of the highest incidences of the disease in the world and the research suggests this is down to a lack of sunshine leaving many Scots with insufficient levels of the essential vitamin.

Previous studies have suggested an association between lower levels of vitamin D and a higher risk of the disabling disease, but scientists have now demonstrated a genetic link between the two.

The study, published in online journal Public Library of Science Medicine, compared thousands of MS sufferers and healthy individuals and found that those whose genetics suggested a lack of vitamin D were at least twice as likely to have MS.

The report has been welcomed by the MS Society Scotland, who claimed the link between the vitamin and the disease is a "crucial area of research".

Dr Susan Kohlhaas, head of biomedical research at the society, said: "There are many unanswered questions around what causes MS so this large scale study is an exciting step towards understanding more about the complex nature of the genetic and environmental factors that contribute to it.

"There are government guidelines around how much vitamin D people should take, and taking too much can lead to side effects so we’d encourage people to talk to their health professional if they’re thinking of doing this.

"We’d also welcome more research into this area, as we know it’s really important to people living with MS."

Report author Dr Brent Richards, from McGill University in Canada, said the study helped to explain why rates of MS, a potentially disabling auto-immune disease that damages nerve fibres, are higher in high latitude regions such as northern Europe which have fewer sunny days.

He 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."

In 2013, an 'Atlas of MS' - produced by the Multiple Sclerosis International Federation - showed that the prevalence of the disease in Scotland was 188 cases per 100,000 people in the population, slightly behind Northern Ireland at 190 but higher than the 138 cases in Wales and 162 in England.

This revealed that, at that time, around 10,000 people were living with the condition in Scotland.

Earlier this month, health professionals urged Scots - especially pregnant women, children and teenagers - to take vitamin D supplements in a bid to prevent a range of illnesses, including MS.

Experts have now welcomed the new study, with one immunologist calling for foods to be supplemented with the vitamin as a public health measure.

Professor Danny Altmann, from Imperial College London, said: "Vitamin D is relatively cheap, safe and many of us would be all the healthier if we could achieve the serum levels that our ancient ancestors presumably acquired when roaming outdoors in temperate climates, unclothed and eating a diverse diet including oily fish.

"While it may be too much to expect therapeutic vitamin D to treat or reverse ongoing MS, this paper will add to the weight of argument for routine vitamin D supplementation of foodstuffs as a broad, preventative, public health measure."

Dr Benjamin Jacobs, from the Royal National Orthopaedic Hospital, added: "This study reveals important new evidence of a link between Vitamin D deficiency and multiple sclerosis (MS).

"The results show that if a baby is born with genes associated with vitamin D deficiency they are twice as likely as other babies to develop MS as an adult. This could be because vitamin D deficiency causes MS, or possibly because there are other complex genetic interactions."

Harry Potter author JK Rowling has previously spoken about her mother's battle with the disease following her death in 1990.

The Scottish writer is a patron of the MS Society Scotland and in 2010 donated £10m to a new centre researching the disease.