New Clues to the Mystery of Multiple Sclerosis
Sun exposure and vitamin D status are independently important factors
Scientists have long observed that the farther you live from the equator, the greater your risk of developing multiple sclerosis, an autoimmune disease that affects the nerve cells. New research points toward related connections that may explain this phenomena: more sun exposure over a lifetime and higher vitamin D levels were each associated with a lower risk of nerve damage that can progress to multiple sclerosis.
Looking north to south
The study, published in Neurology, included Australians living from latitudes 27S to 43S. These latitudes receive about the same amount of annual sunlight as a region extending from Tampa, Florida, to Concord, New Hampshire, and from Baja California, Mexico, to Eugene, Oregon.
Study participants were 216 people who had recently been found to have the type of nerve damage seen in multiple sclerosis, known as demyelination. They were compared with 395 otherwise similar people without demyelination. All participants answered questions about their past, recent, and total leisure-time sun exposure. They also had their skin examined and rated for sun damage, and blood levels of vitamin D (25-hydroxy) measured.
How sun and vitamin D relate to nerve damage
Similar to previous studies, this one found that more people with the demyelination type of nerve damage lived in the far southern latitudes than the middle latitudes. Moreover:
"Our findings suggest that sun exposure and vitamin D status are independently important factors in the development of multiple sclerosis," said study lead author Associate Professor Robyn Lucas of the Australian National University. "If this is true, vitamin D supplementation alone may be less effective as a preventive strategy than previously thought."
Take care of your nerves
While many people may be out enjoying the summer sun while they have it, it's worth a discussion with your doctor on the relative risks of premature aging and skin cancer compared with multiple sclerosis risks. In any case, if you live in a place where summers are short, you might want to take extra steps in the hope of preventing nerve damage:
Maureen Williams, ND, received her bachelor's degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice on Cortes Island in British Columbia, Canada, and has done extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.