Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Multiple Sclerosis Health Center

Font Size

Sun Exposure Linked to MS Risk

Sun Exposure During Childhood May Help Protect Against Multiple Sclerosis in Adulthood
WebMD Health News
Reviewed by Louise Chang, MD

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.”

Today on WebMD

nerve damage
Learn how this disease affects the nervous system.
woman applying lotion
Ideas on how to boost your mood and self-esteem.
woman pondering
Get personalized treatment options.
man with hand over eye
Be on the lookout for these symptoms.
brain scan
worried woman
neural fiber
white blood cells
sunlight in hands
marijuana plant
muscle spasm