Does Sun Exposure in Early Life Reduce Multiple Sclerosis Risk?

Multiple sclerosis (MS) is an autoimmune central nervous system disorder that affects the brain and spinal cord. It causes white blood cells, which normally protect against infections to enter the nervous system and cause damage. 

In MS antibodies against myelin are produced by the immune system, causing damage to this protective sheath. 

It is estimated that more than 2.3 million people worldwide have received a diagnosis of MS according to the National MS Society. The onset of MS typically occurs between the ages of 20 and 50 years, but 3-10% of these individuals begin experiencing symptoms at an early age, before 18 years of age. 

Pediatric MS is multiple sclerosis that begins in children or teens. About 98% have relapsing-remitting MS, versus 84% of adults with MS. This means that symptoms come and go (relapse and remit). When symptoms are gone, the disease is still able to progress. This condition may also be called pediatric-onset multiple sclerosis (POMS), early-onset MS, or juvenile MS. 

New Study on MS and Sunlight Exposure

A recently published study in the journal Neurology has found a possible link between time spent outdoors and a lower risk of developing MS in children.

The study suggests that those who experienced more sun exposure during their first year of life have lower odds of developing MS. 

Researchers understand that the causes of adult-onset MS include a combination of factors, including genetic predisposition, low sun exposure, low ultraviolet radiation exposure and low vitamin D concentrations. 

The researchers recruited participants from 16 pediatric hospitals across the US and included volunteers who had received a diagnosis of MS before the age of 18, which included around 330 people.

Control participants had no personal history of autoimmune disease, no severe health conditions and no parental history of MS. The study included 540 controls from the same hospitals and matched them according to age and gender with the participants with MS.

The researchers measured sun exposure as time spent outdoors at different ages and in the most recent summer, and the use of sun protection such as hats, clothing, and sunscreen. They based the amount of ultraviolet light exposure for each participant on their birthplace and residence at the time of the study. The researchers also took blood samples from all participants.

The researchers adjusted for factors that could affect MS risk, such as smoke exposure and gender. Their analysis of the resulting data indicated that participants who daily spent an average of 30 minutes to an hour outside in the summer before the study had a 50% lower risk of MS.

When the time spent outdoors averaged between 1 and 2 hours daily, the risk of MS was 81% lower. Data also indicated that greater time spent outdoors in the first year of life had associations with a lower risk of developing MS.


Leigh Ann Green (2021, Dec 14). Could exposure to sunlight reduce MS risk in children? Medical News Today. Retrieved from:

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