In this study there is a link between hospital admissions due to MS in Scotland and the average vitamin D levels in the previous 4 months. As you can see from the graphs above the greatest admission rates were in Spring (April to June) when vitamin D levels are the lowest.
"This suggests that low vitamin D levels are associated with whatever causes MS'ers to be admitted to hospital, i.e. relapses and infections."
"We know from numerous other studies that being deficient in vitamin D affects your immunity and increases your risk of infections and probably relapses."
"This study is another reason to make sure that you are vitamin D replete. There is not enough good quality sunshine in the UK to do this so you need to take supplements. I advocate 5,000U of vitamin D3 per day."