Women who are not exposed to sufficient sunshine in pregnancy may be at risk of giving birth to a child who will get multiple sclerosis in adulthood, research reveals today.
Oxford University researchers have identified a link between a shortage of the "sunshine vitamin" – vitamin D – and a specific gene which appears to be involved in the onset of the devastating and incurable disease.
Women are already urged to take folic acid in pregnancy to reduce the chances of a child being born with spina bifida. The research findings suggest that vitamin D could before long be advised for pregnant women as well – especially those who do not get much exposure to sunlight. The researchers think it is possible that vitamin D could play a part in other diseases whcih affect the immune system too.
"Our study implies that taking vitamin D supplements during pregnancy and the early years may reduce the risk of a child developing MS later in life," said lead author Dr Sreeram Ramagopalan. "Vitamin D is a safe and relatively cheap supplement with substantial potential health benefits. There is accumulating evidence that it can reduce the risk of developing cancer and offer protection from other autoimmune diseases."
Their work, published today in the journal PLoS Genetics, breaks new ground by revealing the interaction between a gene and an environmental factor – in this case, exposure to sunlight.
It has long been suspected that sunshine played a part in the condition's development. MS, the most common disabling neurological condition, affects 85,000 mainly young adults in the UK and 2.5 million worldwide and is markedly more common in cloudy northern climates. Scotland has a significantly higher concentration of MS cases than England.
A gene variant known as DRB1*1501 has been implicated in MS. While one in 1000 people in the general population develop the disease, it is one in 300 among those who have one copy of this gene variant and one in 100 of those who have two copies.
The Oxford study has found a direct relationship between vitamin D, produced in the body as a result of sun exposure, and this gene variant. In effect, proteins activated by vitamin D in the body switch the gene on. It appears, they say, that if people get too little sunshine, the gene may not function properly.
This interaction between gene and environment – so-called "epigenetics" – is being seen as increasingly important by scientists: that genetic make-up is not set in stone from conception, but is influenced for better or worse by the world around us.
"Epigenetics will have important implications, not only for MS, but for other common diseases," said Professor George Ebers, from the Wellcome Trust Centre for Human Genetics at Oxford, where the work was done. "For mothers, taking care of their health during their reproductive years may have beneficial effects on the health of their future children or even grandchildren."
· This article was amended on Friday 6 February 2009. George Ebers does not run the Wellcome Trust Centre for Human Genetics at Oxford. This has been corrected.
