Children and adults who live in areas where they are exposed to more of the sun’s rays may have a reduced risk of developing multiple sclerosis a year later. Exposure during childhood and young adulthood can also make the disease development less likely.
“While previous studies have shown that more sun exposure may contribute to a lower risk of MS, our study went further looking at exposure over a person’s lifespan,” said Helen Tremlett, P.h.D, of the University of British Columbia in Vancouver, Canada, and lead author of the study.
Multiple sclerosis is a potentially disabling neurological disease that affects the brain and spinal cord. Canada is said to have the highest prevalence of multiple sclerosis in the world, according to the MSSociety.
Tremlett and her team sifted through data on 151 women with MS and 235 others of similar age without the disease who were all participating in the Nurses’ Health Study based in Boston. 98 percent of the women were white while 94 percent of them said that they had fair to medium skin.
The women lived across the United States in various regions with different climates. For the study, the participants had to complete questionnaires about summer, winter and lifetime sun exposure. According to the researchers, the average age at MS onset was 40.
The participants were divided into three groups, depending on the sun exposure rate of each woman. Researchers focused on a number of factors when determining this aspect such as latitude, altitude, and average cloud cover for each location. More so, seasonal sun exposure was explored, with high summer sun exposure defined as more than 10 hours per week and more than four hours per week in the winter.
Researchers found that women who lived in sunnier climates with the highest exposure to UV-B rays were 45 percent less likely to develop MS. This applied to all pre-MS onset age groups as opposed to those living in regions with the lowest UV-B ray exposure.
Tremlett said that the findings imply a beneficial association, however, she still cautioned people to avoid prolonged exposure to the sun as it’s been known to lead to skin cancer development.
The study was published in the journal, Neurology.
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