Researchers in Sweden report finding no association between vitamin D levels at birth and the risk of developing MS later, despite strong evidence that low vitamin D levels in adulthood are associated with increased risk of getting MS. The study, which involved testing stored blood samples from hundreds of people, adds to the growing body of knowledge on the factors that may contribute to development of MS. Peter Ueda, MD, PhD, and colleagues (Karolinska Institute, Stockholm) report their findings in Annals of Neurology (published online July 10, 2014)
Background: A number of genetic and environmental factors are associated with whether a person will get MS. Research is increasingly pointing to a reduced level of vitamin D in the blood as a risk factor for developing MS. Vitamin D is produced by the body when the skin is exposed to sunshine, and it can also be found in some foods. In lab mice, vitamin D supplementation can reduce the effects of an MS-like disease. In people with MS, high vitamin D levels have been associated with decreased risk for attacks and less severe disability. Clinical trials, including one supported by the National MS Society, are underway to test whether vitamin D supplements, added to standard therapy, can reduce disease activity in people who have MS.
The Study: Participants were drawn from the Epidemiological Investigation of MS, a study that recruited people with MS from 40 study centers throughout Sweden who were born from 1975 and onward. The investigators reviewed information on 459 people with MS and 663 controls without MS. They obtained information on sun exposure, smoking and other lifestyle and work-related information using questionnaires sent to the identified cases and controls and filled out at home. To determine vitamin D levels at birth, the investigators obtained participants’ consent to examine dried neonatal blood samples that have been collected by a Swedish biobank to screen for rare metabolic diseases in infants since 1975.
No association was found between vitamin D levels at birth and risk of developing MS later in life. The authors also looked at factors that might have confounded these results, including socioeconomic group, area and season of birth, breastfeeding, body mass index, vitamin D intake from dairy products, fatty fish consumption, sunlight exposure, and smoking. Even after accounting for these factors, no association was found.
Conclusion: This study supplies new and surprising information that may serve to refine our understanding of factors that influence who develops MS. The authors note that this study did not account for possible susceptibility and protective genes at play in those who were studied, which may have influenced their findings. “Further investigations assessing potential gene-environment interactions with respect to vitamin D during gestation, and the relation between vitamin D in early parts of gestational life and risk of MS could therefore be warranted,” they conclude.
Read more about research on vitamin D and MS.