- A study based on stored blood samples of 800,000 pregnant Finnish women found that vitamin D levels might predict who is at risk for later developing MS.
- Vitamin D blood levels of 1,092 women later diagnosed with MS were compared to those of 2,123 women around the same age and region who did not develop the disease.
- Women who developed MS later had average D levels lower than the women who didn’t.
- More research is needed on how to best supplement vitamin D and to know whether and who it might help. Read more more about Vitamin D and MS.
- The study was published on September 13, 2017 in Neurology.
Background: Researchers believe that several genetic and environmental factors influence whether a person will get MS. These factors may also impact the severity of the disease. Scientists are eager to find risk factors for MS that can be modified to possibly prevent MS and reduce disease activity. Research is increasingly pointing to reduced levels of vitamin D in the blood as a risk factor for developing MS, and studies are underway to determine if vitamin D levels influence MS disease activity.
This Study: This study -- the largest such study to date – took advantage of a unique resource: stored blood samples from 800,000 Finnish women who had undergone routine prenatal testing during pregnancy. The study was designed to determine whether and to what extent vitamin D deficiency is associated with future risk of developing MS. The team identified 1,092 of the women who were later diagnosed with MS. The researchers compared their vitamin D levels to those of 2,123 women who were about the same age and lived in the same area but did not develop MS. Of those women whose medical records were available for examination, an average of 9.5 years had lapsed between the time of the first blood sample and the date of an MS diagnosis. For this study, classifications of blood levels of vitamin D (25-hydroxyvitamin D) included “deficient” (less than 30 nmol/L) and “adequate” (greater than or equal to 50 nmol/L).
Results: The team found that overall as vitamin D levels increased, the risk of later developing MS decreased. Women with the greatest deficiency in vitamin D had a twofold increase in the risk of developing MS, and those with the highest vitamin D levels had the lowest risk of a later MS diagnosis. Most of the women in the study were considered to have deficient or insufficient levels of vitamin D. Of the women who developed MS, 58 percent had deficient levels of vitamin D, compared to 52 percent of the women who did not develop the disease.
The researchers conclude that the results directly support vitamin D deficiency as a risk factor for MS and that correcting this among reproductive age women may reduce their future risk of developing MS. In addition, a previous study of this same group of women found that maternal vitamin D deficiency during pregnancy doubled the risk of MS in their offspring, and a Danish study found that low vitamin D levels in infants was associated with an increased MS risk in adulthood, suggesting that improving a woman’s vitamin D levels during pregnancy may also reduce the risk of MS in her children.
The study, by a team including Drs. Kassandra Munger and Alberto Ascherio (Harvard T. H. Chan School of Public Health in Boston), was published on September 13, 2017 in Neurology.
Comment: This largest study of its kind to date adds to growing evidence that low levels of vitamin D increase the likelihood of developing MS. Since this study included only women, who were mostly white, the results may not apply to men or to other racial groups. It also did not account for other potential risk factors that may have played a role.
An editorial in the same issue of Neurology by Drs. Ruth Ann Marrie Christopher Beck addresses the question of whether there is enough evidence now to make sweeping recommendations on vitamin D supplementation. They note, “Vitamin D supplementation is a simple intervention that would be highly cost-effective even if it prevents only a proportion of MS cases...,” concluding, “It is time to take an active approach to preventing MS, at a minimum targeting those individuals with an elevated risk of MS, including smokers, the obese, and those with a family history of MS.” Read more more about Vitamin D and MS