Scottish researchers say babies born in April have higher risk of MS

From The Telegraph in the UK:

Scientists found mothers who were pregnant during the autumn and winter were most likely to give birth to those who would suffer from the debilitating neurological disease.

The researchers, based at Glasgow university and the city's Southern General Hospital, believe the spike in cases among children born in the spring may be due to a shortage of vitamin D because during a vital developmental stage their mothers are exposed to less sunshine.

Vitamin D, which is largely gained through sunlight and food, is known to regulate a gene that can predispose individuals to MS. If the gene is passed on to the unborn child, without being regulated by a sufficient amount of vitamin D, it could "hard wire" them to develop the disease in later life.

The new study, published in the European Journal of Neurology, is the biggest yet carried out in Scotland, which has the highest rate of MS in the world.

MS affects about 85,000 people in the UK and 10,500 in Scotland. While the cause is not known, experts believe a combination of genetic and environmental factors are responsible for the condition.

The Glasgow researchers examined data on about 1,300 MS patients born in the west of Scotland between 1922 and 1992. They found that about 400 people born in March, April and May went on to develop MS, 22per cent higher than expected. Almost half of all male and a quarter of female sufferers were born in April.

By comparison, there were about 16per cent fewer MS births in the autumn months. Those born in November had the lowest incidence of the disease.

Dr Colin O'Leary of the institute of neurological sciences at the Southern General and co-author of the study, said several theories about the condition were being explored.

"It's a very interesting observation and springtime seems to be a period of relatively high risk," he said.

"Seasonal risk may be a reflection of adverse events that occurred at the time of birth, in utero in the preceding nine months, or during the months following birth, when the central nervous system continues to undergo rapid development.

"There could be an association between reduced sun exposure and vitamin D levels." O'Leary now plans to carry out a UK-wide study with scientists in Oxford.

Professor George Ebers, from Oxford University's department of clinical neurology at the John Radcliffe Hospital, said: "The difference [in developing MS in Scotland] between being born in April versus November is an astounding 50per cent. This is real, there's no doubt of a seasonal link. There are different theories, but I think the April excess of births could be linked to a sunlight deficiency.

"The focus is on trying to prove what the environmental effect is and, pending conclusive demonstration of that effect, some people might view it as prudent to conceive at certain times of the year to lower their child's MS risk if there is a history of the disease in the family."

Ryan McLaughlin, 14, from Glasgow, whose mother has MS, launched a campaign for all pregnant women and young children in Scotland to be given Vitamin D supplements.

A spokeswoman for the Scottish government, said: "Much of the evidence of a link between vitamin D and MS is still at a very early stage. We will continue to review all well-conducted research across the world. If the recommendations on vitamin D change we'll make the appropriate arrangements."