Multiple sclerosis remains mysterious. The cause is uncertain and the course of the disease is unpredictable. In this disorder the immune system runs amok and attacks the myelin sheath that insulates nerves. Symptoms can include numbness, muscle weakness, difficulty with balance and coordination, fatigue and many others. Although there are new drugs to treat MS, there is no cure.
A new epidemiological study from England suggests that two factors may predispose susceptible patients to MS. The investigators analyzed data over seven years and found the highest rates of MS occurred in areas that had less sunlight and higher rates of the infectious disease mononucleosis. The researchers speculate that if vitamin D levels are too low, the immune system may not be able to ward off late complications of the Epstein Barr virus that causes mono. Previous studies have shown lower rates of MS where sun exposure is stronger, suggesting that there may be something about vitamin D levels that is protective.
[Neurology, online, April 18, 2011]