A study of nearly 600 children with multiple sclerosis reported that genes linked to low vitamin D levels and obesity contribute to the risk of developing MS in childhood.
While the two are also risk factors for adult-onset MS, obesity and low vitamin D have a larger risk impact on children than adults.
The findings provide hope that awareness of these risk factors might prevent MS in both children and adults.
The study, “Evidence for a causal relationship between low vitamin D, high BMI, and pediatric-onset MS,” was led by researchers at the University of California, San Francisco and Berkeley and involved patients from pediatric MS centers in both the U.S. and Sweden. The work was published in the journal Neurology.
To explore triggers of MS in children — making up 5 percent of all disease diagnoses — the research team recruited 569 MS-affected children and 16,251 controls. Participants were all non-Hispanic whites.
Researchers created what they called a genetic risk score to analyze how these two factors influence MS risk. The scores — one each for vitamin D and obesity — were based on the presence or absence of three genetic variations impacting vitamin D levels, and 97 variations linked to body weight.
For the analyses, researchers also took into account numerous other risk factors, as well as sex and genetic ancestry.
Both low vitamin D and increased body weight increased the risk of MS, and their impact was seen to be greater in children than in adults.
The study is not the first to explore obesity and vitamin D in MS children. Last year, researchers found a link between obesity and MS, but suggested that the impact of obesity might determine vitamin D, since the vitamin is often lower in obese people.
The new study showed this is not the case: Obesity and low vitamin D independently drive MS risk. The study was also an elegant way of showing how genes and environmental factors may interact to trigger MS.
“These results add to the growing evidence of genetic and environmental factors in the risk of developing pediatric-onset MS. Knowing that both low vitamin D levels and obesity are risk factors has potential implications for preventing MS in children and adults,” the National MS Society — which partly funded the study — wrote in a press release.