Children who are exposed to more sunshine may be less likely to develop inflammatory bowel disease (IBD), a study suggests.
The study, titled “Higher Sun Exposure is Associated With Lower Risk of Pediatric Inflammatory Bowel Disease: A Matched Case-Control Study,” was published in the Journal of Pediatric Gastroenterology and Nutrition.
Pediatric IBD is associated with both genetic and environmental risk factors. Recent studies have shown that the incidence of IBD in children is associated with increasing distance from the equator (at least in the Northern hemisphere) and also living in locations with more months of low daily sunlight.
“There are not yet any studies investigating, at the individual level, whether greater exposure to UV radiation is associated with a reduced risk of IBD onset,” the researchers wrote.
In the study, they recruited 99 children with IBD from hospitals in Melbourne, Australia. They also recruited 396 children without IBD who were at the hospital for other reasons. The two groups were similar in terms of age and sex, and both groups were given a questionnaire to assess the amount of sun exposure they typically get.
The researchers then looked to see whether the children’s amount of sun exposure was associated with their chances of having IBD.
They found that, for every 10 minutes of sunshine exposure, the children’s chances of having IBD went down by 6%, even after the researchers adjusted for other factors, including age, race, and physical activity.
“It doesn’t have to be all at the same time,” Robyn Lucas, PhD, a professor at The Australian National University and an author of the study, said in a press release. “But, we found children who were outside and exposed to the sun for an extra half hour a day in total, had a lower risk of developing IBD by almost 20 per cent.”
Accumulating evidence suggests that sunlight — specifically, ultraviolet radiation — hitting the skin and/or eyes produces positive effects in the immune system, such as helping to activate regulatory immune cells that can reduce inflammation. However, the details of this connection are still unclear.
“At this stage, what we have shown is there is a link between lack of sun exposure and increased risk of IBD,” Lucas said. “We already know that sunshine affects the immune system in ways that could decrease IBD — but we don’t know the exact pathways.”
Lucas also noted that getting a daily dose of sunshine does not mean that good practices for sun protection (sunscreen, etc.) should be discarded.
“Everyone needs a bit of sun exposure every day or at least most days of the week, but we are not talking about sunbaking or getting sunburnt,” she said. “If we can reduce the risk of developing IBD, it is worth the trouble to get outdoors and get some sun — but do it safely, following Cancer Council guidelines.”