MS children exposed to sunlight as babies see less relapse risk
30 minutes a day of sunshine in 1st year of life tied to lower disease activity
Children with multiple sclerosis (MS) who were exposed to sunlight for at least half an hour per day during the first summer of life tend to have less disease relapses than those who received less sun exposure during that period, a study found.
The risk of relapse was also significantly lower in children with MS whose biological mothers had received 30 minutes or more of sun exposure per day during the second trimester of pregnancy.
“Our findings suggest that sun exposure in early childhood may have long-lasting benefits on the progression of childhood-onset MS,” Gina Chang, MD, co-author of the study and a child neurology resident at Children’s Hospital of Philadelphia, said in a news story from the American Academy of Neurology.
The study, “Association Between Sun Exposure and Risk of Relapse in Pediatric-Onset Multiple Sclerosis,” was published in the academy’s journal, Neurology Neuroimmunology and Neuroinflammation.
Reduced exposure to sunlight has been identified as a key risk factor for multiple sclerosis. While the mechanisms for this association remain to be fully elucidated, sun exposure is known to be required for the synthesis of vitamin D, which has an important anti-inflammatory role in MS.
Sunlight and MS
Sunlight exposure in early life has been shown to affect the risk of developing pediatric-onset multiple sclerosis (POMS), a rare form of the disease that develops during childhood or adolescence. However, there hasn’t been much investigation into how sunlight exposure affects the course of the disease in people who develop POMS.
Scientists analyzed 334 children and adolescents with POMS, with a median age of onset of 15.2, who were followed over several years in the 2010s. About two-thirds (62%) of the patients experienced at least one MS relapse, a flare in which symptoms suddenly worsen, from disease onset to the end of follow-up.
Detailed questionnaires were used to assess exposure to sunlight from pregnancy through childhood. The researchers then constructed statistical analyses to look for associations between sunlight exposure and risk of relapse in MS children and adolescents.
Results showed that children who had received at least 30 minutes of sunlight exposure per day during the first summer of life were significantly less likely to experience relapse, by 33% relative to children with less sunlight exposure during the first summer. There wasn’t any significant association between more recent sunlight exposure and relapse risk.
“In this pediatric cohort study investigating the effect of sun exposure at various life stages on prospective MS course, we found that higher levels of early childhood sun exposure, specifically spending 30 minutes or more (compared with less than 30 minutes) outdoors in the sun in the first summer of life, were associated with a reduced risk of relapse,” the researchers wrote.
Data also indicated that children whose mothers spent at least 30 minutes in the sun each day during the second trimester of pregnancy were 32% less likely to experience relapses. Children born during the summer also had lower relapse risk compared with kids born in winter, the researchers noted.
“These novel findings suggest that sun exposure in early development may have long-lasting benefits on subsequent MS course, possibly through modulation of the immune response,” the scientists wrote.
The team stressed that more research is needed to determine why early-life sunlight exposure seems to affect the course of POMS, but they said the findings might lay the groundwork for future trials to test sunlight or ultraviolet light exposure as a possible strategy for treatment.
“Future studies should look at how time in the sun at other time periods before and after MS diagnosis affects disease course, to better guide sun exposure recommendations for children with MS and to help design potential clinical trials,” Chang said.
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