A new study suggests that vitamin D levels for patients in the early stages of multiple sclerosis (MS) predict the disease’s severity and how quickly it progresses.
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The findings, recently published online in JAMA Neurology, suggest that patients in the early stages of MS could stave off disease symptoms by increasing their vitamin D intake.
MS is an incurable inflammatory disorder that affects the brain and spinal cord. Infection-fighting white blood cells enter the nervous system and strip off the myelin sheath that protects nerves. As a result, the nerves cannot conduct electricity as well as they should. In addition, the nerves can become severed, which prevents the brain from controlling the body as it normally would. Symptoms, which can be intermittent or progress over time, can include numbness, paralysis and loss of vision.
In the study, researchers at the Harvard School of Public Health found that people with lower vitamin D levels were more likely to develop new brain lesions and had a worse prognosis than those with higher levels. This association was seen regardless of whether the patients were on an established MS therapy.
Explaining the latitude connection
“The study is getting at an important question,” says neurologist Robert Fox, MD, of the Mellen Center for Multiple Sclerosis at Cleveland Clinic. “We have come to a growing appreciation of how low vitamin D is a risk factor in the development of MS.”
It’s long been observed that people who live farther away from the equator are more likely to have MS. Physicians and researchers have theorized that exposure to the sun – and the vitamin D it provides – may hold some clue to MS.
“No one understood that and this may explain it,” Dr. Fox says. “These are very robust findings because they looked at many different clinical outcomes and had very consistent findings.”
Deficiency is common
The study, however, shows only an association – and not a causal relationship – between vitamin D levels and MS, Dr. Fox says. It’s unknown whether vitamin D is the source of improved health to people with MS.
Cleveland Clinic is one of several sites nationwide enrolling patients in a randomized clinical trial aimed at finding this out. The study, sponsored by the National Multiple Sclerosis Society, will compare the effectiveness of the current recommended amount of vitamin D supplements vs. high-dose vitamin D supplements at reducing MS disease activity, when added to standard therapy.
Dr. Fox says many neurologists routinely recommend their MS patients take vitamin D supplements because low levels are common. About 20 percent of MS patients in the United States have a vitamin D deficiency.