Medindia LOGIN REGISTER
Medindia
More Summer Sun may Mean Lower Risk of Multiple Sclerosis

More Summer Sun may Mean Lower Risk of Multiple Sclerosis

by Anjali Aryamvally on Mar 9 2018 3:39 PM
Listen to this article
0:00/0:00

Highlights:
  • People who are more exposed to the sun’s rays are less likely to develop a neurological condition called multiple sclerosis (MS).
  • People who lived in sunnier climates with the highest exposure to UV-B rays had 45% reduced risk of developing MS.
  • The UV-B rays from the sun stimulate the production of vitamin D in the body which is important in reducing the risk of MS.
Where a person lives and the ages at which they are exposed to the sun's rays may play an important role in reducing the risk of multiple sclerosis (MS), according to a new study. People who live in sunnier climates and are more exposed to the sun’s rays are less likely to develop MS later in life, shows study. The study found that exposure to the sun’s rays during childhood and young adulthood reduced the risk of MS. The study is published in the journal Neurology.

Advertisement

Multiple Sclerosis and the Sun

Multiple sclerosis is a disease that affects the central nervous system that includes the brain and the spinal cord. In MS, the protective layer of the neurons called the myelin is attacked by the immune system, thereby disabling neuronal communication between the brain and the rest of the body.
Previous studies have linked low levels of vitamin D to an increased risk of MS. But exposure to the sun’s rays, specifically the UV-B rays help the body produce vitamin D and thereby plays an important role in reducing the risk for MS.

"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 study author Helen Tremlett, PhD, of the University of British Columbia in Vancouver, Canada.


Advertisement

Study Overview

The study included 151 women with MS and 235 women of similar age without MS who were identified from the larger Nurses' Health Study. About 98% of the participants were white and 94% had fair to medium skin. The participants lived across the US in a variety of climates. Among those with MS, the average age at onset was 40.

The participants were given questionnaires about lifetime summer and winter sun exposure. Based on the answers to the questionnaire, the women were divided into three groups: low, moderate and high UV-B ray exposure.

Advertisement

Study Findings

  • Based on place of living: Women who lived in sunnier climates with the highest exposure to UV-B rays had 45% reduced risk of developing MS compared to women who lived in areas with the lowest UV-B ray exposure.
  • Based on age: Women who lived in areas with the highest levels of UV-B rays between ages 5 to 15 had a 51% reduced risk of MS.
  • Also, women who spent more time outdoors in the summer during the ages 5 to 15 in locations with high exposure to UV-B rays had a 55% reduced risk of developing MS during adulthood compared to those with the lowest exposure.
"Our findings suggest that higher exposure to the sun's UV-B rays, higher summer outdoor exposure and lower risk of MS can occur not just in childhood, but into early adulthood as well," said Tremlett.

Limitations of the study

  • Sun exposure was self-reported by the participants
  • Almost all participants were female and white thereby the results of the study may not apply to other populations.
References:
  1. Helen Tremlett, Feng Zhu, Alberto Ascherio and Kassandra L. Munger. Sun exposure over the life course and associations with multiple sclerosis. Neurology, March 7, 2018 DOI: 10.1212/WNL.0000000000005257
Source-Medindia


Advertisement