Vitamin D deficiency before and after birth may increase the risk of multiple sclerosis in some individuals, a study has shown. Scientists have found evidence that MS susceptibility is influenced by vitamin D levels coupled with a common genetic variant.
Children with the gene mutation may be more at risk of developing the disease if they lack vitamin D while growing in the womb or during their early years of life. The researchers suggest that as a precaution mothers should take vitamin D supplements during pregnancy or give them to their young children.
MS is the most common disabling neurological condition affecting young adults. More than 85,000 people in the UK and 2.5 million worldwide are thought to suffer from the condition, which results from the loss of nerve fibres and their protective myelin sheath "insulation". Although the causes of MS are unclear, experts believe both environmental and genetic factors play a role.
Previous studies have shown that populations from northern Europe are more at risk of MS if they live in areas with little sunshine. This could be explained by the link with vitamin D, which is produced in the skin through the action of sunlight.
The largest genetic influence on MS is known to arise from a gene variant called DRB1*1501 and neighbouring DNA sequences. While one in 1,000 people in the UK is likely to develop MS, the incidence rises to around one in 300 for those carrying a single copy of the variant. People with two variant copies of the gene pair have a one in 100 chance of developing the disease.