Dr Kassandra Munger on Vitamin D and Multiple Sclerosis

Kassandra Munger, ScD, of the Harvard TH Chan School of Public Health, discusses findings that vitamin D deficiencies are linked to a greater risk of multiple sclerosis.

Transcript:

The associations between vitamin D and MS, they were first shown in the animal studies, which is where we sort of get the inkling that maybe there really was something here, because it had been observed—I'm sure you're aware of the latitude gradient with MS, where, historically, the prevalence of the disease has been higher in the higher latitudes then lower latitudes. Adjusting that sun exposure might have a role and of course, the primary source of vitamin D from people is sun exposure. And you get over the course of a year less sun exposure in more northern latitudes than in latitudes closer to the equator. In the mid 2000s, we decided to take a look at vitamin D intake from diet and risk of MS in our Nurses Health Study cohort. We have 200,000 nurses, many of whom have been supplying us with information on their diets for a number of years among other risk factors, other factors. And in those cohorts, we saw that women who were had a higher intake of vitamin D from supplements had a lower risk of MS. And so even from there to our military study, again, those same samples where we were able to look at [Epstein-Barr virus] EBV, we measured the vitamin D levels. And so in presumably otherwise healthy young individuals, those with higher levels of vitamin D had a lower risk of MS. And then conversely, in the Finnish maternity cohort study, we have a lot of a high percentage of people who were vitamin D deficient, so we’re are able to look at the other end of the scale, if you will. Women who had vitamin D deficiency, and insufficiency in those women, was associated with about a 2-fold increased risk in MS. So we've been able to show the increased risk with low levels of vitamin D, the decreased risk with high levels of vitamin D. Then there have been some other studies which have also shown the same effect.