Link between multiple sclerosis and vitamin D deficiency and other stories . . .

Multiple sclerosis and vitamin D deficiency have often been linked. This association has been confirmed by a mendelian randomisation study in PLoS Medicine (2015, doi:10.1371/journal.pmed.1001866), which showed that people with genetically determined reduced levels of 25-hydroxyvitamin D are at increased risk of multiple sclerosis (MS). Meanwhile, a study of 2301 people with MS suggests that levels of sunlight and vitamin D supplementation may also affect the severity of symptoms in people with established MS (BMC Neurology 2015;15:132, doi:10.1186/s12883-015-0394-1). After adjusting for confounders, the likelihood of disability increased the further that patients were from the equator.

Ireland is far from the equator and is prey to Atlantic weather systems that blot out the sun. A study of three Irish cohorts of mean age 70-80 years found that most had vitamin D deficiency or insufficiency (Age and Ageing 2015;44:847-53, doi:10.1093/ageing/afv090). Taking vitamin D supplements and seeking the sun—in Ireland …