Lower levels of neonatal vitamin D may increase the risk of MS later in life.
MS affects an estimated 2.3 million people across the world.
The exact causes of the disease are not known, but it is believed to appear in genetically predisposed individuals who have also been exposed to a combination of environmental factors.
Although there is currently no known cure for MS, a significant amount of research is being done into its causes, ways to improve therapies and treatment, and means for prevention.
Some previous research has indicated that an increased level of vitamin D may lead to a lower risk of MS.
New research suggests higher levels of vitamin D in pregnant women may help prevent the development of MS for the child in later life.
Assessing levels of neonatal Vitamin D and the risk of MS
Dr. Nete Munk Nielsen, of the State Serum Institute in Copenhagen, Denmark, and team conducted a large population-based, case-control study to examine the association between the neonatal status of 25-hydroxyvitamin D (25OHD) - a marker of vitamin D levels - and MS risk.
The researchers used data from the nationwide Danish MS registry and the Danish Newborn Screening Biobank (DNSB). The DNSB stores dried blood spots samples from newborn screening tests.
They identified and selected everyone born after April 30, 1981, and who had developed MS by 2012. This resulted in a total of 521 people.
Researchers then compared the blood from these people with that of 972 other people of the same sex who had been born on the same date, but who did not develop MS.
The study - published in the journal Neurology - deemed 25OHD levels between 30 nanomoles per liter and lower than 50 nanomoles per liter as insufficient, and levels higher than or equal to 50 nanomoles per liter as sufficient.
Based on their vitamin D level, study participants were divided into five groups. The bottom group had levels lower than 21 nanomoles per liter, while the top group had levels equal to or above 49 nanomoles per liter.
Lower risk of MS found in people with higher Vitamin D levels at birth
The study summed up a total of 136 people with MS and 193 people without the condition in the bottom group of vitamin D levels. In the top group, they gathered only 89 people with MS and 198 without.
Overall, participants with the highest levels of vitamin D were 47 percent less likely to develop MS later in life than those with the lowest levels.
MS risk also seemed to decrease with the increase of 25OHD levels. In fact, for every 25 nanomole per liter increase in neonatal 25OHD, the risk of MS dropped by 30 percent.
According to the authors, their study serves to further confirm the protective role of vitamin D in the development of MS, as well as indicating that vitamin D insufficiency in utero may influence the risk of MS.
"More research is needed to confirm these results, but considering that a high percentage of pregnant women worldwide have low levels of vitamin D our results may provide important information to the ongoing debate about vitamin D supplements for pregnant women."
Dr. Nete Munk Nielsen
However, Dr. Nielsen emphasizes the fact that the study does not demonstrate that increased vitamin D directly reduces the risk of MS, but rather only presents an association.
He goes on to highlight some other limitations of the study, such as the age of the study participants. They were only 30 years old or younger, so the study did not consider people who had developed MS later in life.
Additionally, the data available in the National Biobank only accounted for 67 percent of people born with MS during that period.
The authors also note they cannot exclude the possibility that this positive effect is an indirect result of higher 25OHD levels later in life that just happened to associate with increased levels at birth. In this case, supplementing the vitamin D intake in the mother would not reduce the risk of MS in the offspring.