Children, teenagers, and young adults who spent 30 minutes a day outside lowered their risk of multiple sclerosis (MS) in half.

People who live in sunny places and spend a lot of time outside may be more likely to get skin cancer but a new paper from UC San Francisco and the Australian National University researchers found that in children and young adults, sun exposure may help protect against multiple sclerosis.

The study is based on research done by other scientists who found a link between more ultraviolet exposure in childhood and a lower risk of adult MS.

The research involved 332 participants aged 3 to 22 who had been diagnosed with MS for an average of seven months. Their locations and degree of sun exposure were matched by age and gender to 534 participants without MS.

In questionnaires completed by participants with MS or their parents, 19% reported spending fewer than 30 minutes everyday outside during the previous summer, compared to 6% of those who did not have MS. When the researchers controlled for MS risk factors such as smoking and female sex, they discovered that participants who spent an average of 30 minutes to one hour outside daily had a 52 percent lower risk of MS than those who spent less than 30 minutes outside daily.

“Sun exposure is known to boost vitamin D levels,” says co-senior author Dr. Emmanuelle Waubant.

“It also stimulates immune cells in the skin that have a protective role in diseases such as MS. Vitamin D may also change the biological function of the immune cells and, as such, play a role in protecting against autoimmune diseases.”

While MS typically affects people between the ages of 20 and 50, 3 to 5 percent of the approximately one million patients with the disorder in the United States begin experiencing symptoms as children. Pediatric-onset MS is initially highly inflammatory, but progresses more slowly than adult-onset MS, with secondary progression symptoms such as moderate to severe weakness, poor coordination, and bowel and bladder control emerging on average 28 years after disease onset, according to specialists. These disability milestones, however, are reached approximately ten years earlier than in adult MS.

The researchers also discovered a relationship between the intensity of sunlight and calculated that residents of Florida would be 21% less likely to have MS than residents of New York.

They noticed that sun exposure was “dose-dependent,” meaning that the longer you were exposed, the lower your risk. Even exposure in the first year of life seems to protect against MS, according to the researchers.

Fortunately, the use of sunscreen does not appear to diminish the therapeutic effects of sunshine in the prevention of MS, according to Waubant, who also serves as the director of the UCSF Regional Pediatric Multiple Sclerosis Center.

Clinical trials are required to assess whether “increasing sun exposure or vitamin D supplementation can prevent the development of MS or alter disease course post-diagnosis,” she said.

Meanwhile, “advising regular time in the sun of at least 30 minutes daily especially during summer, using sun protection as needed, especially for first degree relatives of MS patients, may be a worthwhile intervention to reduce the incidence of MS.”

Other disorders have been linked to a lack of sun exposure and/or low vitamin D levels. Parkinson’s disease, Alzheimer’s disease, and other types of dementia, as well as schizophrenia and other auto-immune disorders such as Type 1 diabetes, Crohn’s disease, and lupus, are examples of these.

Source: Neurology

Image Credit: Getty

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