Genetics

For years, vitamin D has been treated as a kind of “sunshine shield” against multiple sclerosis—low levels are linked to higher risk and more active disease. But does the genetic hand you’re dealt for vitamin D actually change how your MS progresses once you already have it? This post walks through a large study that used vitamin D–related genetic scores in nearly 2,000 people with MS to find out. We unpack what a polygenic risk score is, how it was tested against relapses, disability, MRI changes, and nerve damage in the retina, and why the results challenge the idea that simply pushing vitamin D higher will slow MS. It is a grounded, data-driven look at where vitamin D truly fits in the MS story—important for risk, but probably not a magic lever for progression.