Sun Exposure Linked to MS Risk

Sun Exposure During Childhood May Help Protect Against Multiple Sclerosis in Adulthood

Medically Reviewed by Louise Chang, MD on July 23, 2007
From the WebMD Archives

July 23, 2007 - Spending time in the sun as a child may help protect against multiple sclerosis (MS).

In a new study of identical twins with only one twin having MS, the twin who spent more time in the sun as a child had a lower risk of developing multiple sclerosis than the twin who spent less time in the sun.

Researchers say they aren’t exactly sure why there may be a connection between the sun’s rays and MS. But they say sun exposure may offer protection by boosting the body’s immune system or indirectly reduce the risk by stimulating vitamin D production. Previous studies have shown that vitamin D may lower the risk of MS.

Multiple sclerosis is an autoimmune disease in which the body’s immune system turns against itself and begins attacking healthy tissue, causing symptoms such as muscle weakness and coordination problems. MS is typically diagnosed in early to middle adulthood.

Sun May Protect Against MS

In the study, published in Neurology, researchers surveyed 79 pairs of identical twins in which one twin had MS.

The twins answered questions about whether they or their twin spent more time outdoors during hot days, cold days, and who spent more time sun tanning, going to the beach, or playing team sports as a child.

Overall, the study showed that the twin with MS reported less sun exposure as a child than the healthy twin.

“Our findings note the importance of sun exposure among people with identical genetic risk for MS,” says researcher Thomas Mack, MD, MPH, of the Keck School of Medicine of the University of Southern California in Los Angeles, in a news release. “High priority should be given to research into how sun exposure reduces MS risk if we are to unravel the mystery of what causes MS.”

Show Sources

SOURCES: Islam, T. Neurology, July 24, 2007; vol 69: pp 381-388. News release, American Academy of Neurology.

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