Multiple sclerosis is an autoimmune disease with no cure. There is a significant genetic contribution to risk: Caucasians, women and Northern Europeans are more likely to get MS. Roughly 400,000 people in the US have been diagnosed with MS. It is more prevalent the farther one moves from the equator. A recent CDC study of MS in the United States showed that incidence ranged from 47 per 100,000 population in Texas to 110 in Ohio.
You might speculate that exposure to sunlight is a factor. Many MS researchers would agree, and they believe the key is vitamin D. Vitamin D is well known for its relationship to strong bones, but it also has multiple effects on immune function, and is suspected to protect against autoimmune diseases like MS.
In conditions of strong sunlight, humans make vitamin D in skin. But the farther north one lives, the less vitamin D one makes from sun exposure. Vitamin D synthesis requires exposure to a very specific and narrow band of UV light. Despite the high altitude, Colorado is north of the cut-off point for optimal exposure to those key UV rays. Ohio is also north of that point; Texas is not.
Dr. Tim Vollmer, MD, a University of Colorado neurologist, is an expert on MS. I recently spoke with him about new developments in MS research, particularly related to vitamin D. He described 3 key risk factors for MS:
- low vitamin D exposure, particularly before birth and early in life
- Northern European ancestry (genetics)
- early infections
Dr. Vollmer noted that the correlation with vitamin D status is supported by data from the military. Vitamin D was measured in blood given by recruits and compared to risk for developing multiple sclerosis 5-10 yrs later. Lower vitamin D led to higher risk for MS. In a recent Australian study, relapse rates for MS were higher in patients with low vitamin D.
Knowledge of this vitamin D connection is now so widespread that officials in Scotland are recommending mass vitamin D supplementation to combat the "dire" rates of MS in that northern country. But can we prevent MS with vitamin D supplementation? As yet there is no research that proves this.
According to Dr. Vollmer, it's reasonable to supplement with D until we have an answer. From 1/2 to 2/3 of the people he tests have sub-therapeutic or deficient vitamin D levels. A recent recommendation by the Institute of Medicine only addressed vitamin D for bone health, and he believes this level is inadequate for autoimmune diseases. Low-normal vitamin D levels are insufficient to prevent autoimmune diseases later in life, which are a significant public health issue.
So why is the rate of MS so high in Colorado? Vollmer believes low vitamin D from lack of exposure to sunlight is one issue. People cover up with clothes and sunscreen. We're just not exposing enough skin to make adequate vitamin D. Genetics is another factor. Northern Europeans have a higher frequency of MS, and Colorado was settled by many people of Northern European ancestry.
He cites another complication of modern life: the hygiene hypothesis. Upper and middle class educated people, living in urban areas, have higher MS risk. People who grow up on farms in rural areas do not. According to the hygiene hypothesis, the immune system needs to interact with environment early in life to be trained to recognize true immune theats. Without this biological learning, the immune system is at higher risk of making a mistake and attacking itself, the definition of autoimmune disease.
Can vitamin D be a cure for MS? Vollmer thinks it would only have a modest effect on its own. Vitamin D will likely work best as an add-on treatment for multipile sclerosis. He envisions a study that supplements serum vitamin D along with existing drug therapies, pushing blood levels to around 45 ng/ml, which is above what the IOM recommends for bone health. Eventually he'd like to see a prevention trial for children in families with a history of MS and autoimmune diseases.
Meanwhile, if you have a family history of MS, should you take vitamin D? Will it help you avoid MS? So far, medical research hasn't answered that questions, although Scottish authorities seem to believe it's true. Certainly it's a good idea to be sure your vitamin D level is adequate, whether or not you have a genetic risk. A vitamin D blood test can tell you that. You can easily supplement with vitamin D if your level is low.
The Rocky Mountain MS Center offers information and support for patients. For more detailed information about multiple sclerosis, check out the National Multiple Sclerosis Society website.
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