MS Risk in Children Born to Vitamin D Deficient Women

Research Summary: Vitamin D Status During Pregnancy and Risk on Multiple Sclerosis in Women in the Finnish Maternity Cohort

The background

Many studies have suggested that vitamin D deficiency is associated with an increased risk of developing multiple sclerosis.  This has been correlated with the different risk levels around the world, whereby people living closer to the equator have a much lower incidence rate of MS.  Interestingly, it has been found that this geographic risk level really only applies to where you spend the early stages of your life.  For example, if you grow up in Tasmania and then move to Ecuador when you are 15 years old, your risk of developing MS is not altered by having moved closer to the equator.  Therefore, it is of interest to determine how early in life vitamin D deficiency becomes a factor for increasing the risk of developing MS.

The study

This study by researchers at the Harvard T.H Chan School of Public Health, published in JAMA Neurology, investigated whether vitamin D deficiency during pregnancy impacted on the MS risk of the child.  The study included 193 people with MS for whom maternal blood samples were available and 326 matched healthy controls.  Vitamin D levels were measured and statistical analysis was performed to see if any association with MS risk existed.

The findings

In general, a vitamin D level of between 20ng/mL and 50ng/mL is considered the appropriate range for healthy individuals.  Analysing the available data, the researchers were able to find the following results:

• Almost all mothers included in the study had low levels of Vitamin D – only 10 mothers across the entire study had levels above 30ng/mL
• Severe maternal Vitamin D deficiency (less than 12ng/mL) was associated with a 90% increase in risk of the child developing MS
• An association appeared to exist that suggested the effect was dose-dependent.  This means that as maternal Vitamin D levels increased, the child’s risk of developing MS decreased.  However, the fact that the entire cohort had low Vitamin D levels in general makes this hard to establish in a definitive manner.

The outcomes

This study provides an indication that MS risk may be influenced by Vitamin D deficiency even before birth.  This suggests that thorough monitoring and supplementation during pregnancy may be beneficial to decrease the potential for the child to develop MS, especially in those where a higher risk is thought to exist (e.g. previous family history).  Additionally, knowing that the influence of Vitamin D levels occurs so early in life may help our understanding of how it is conferring it’s effect.

The study does have some rather large limitations that need to be taken into account when assessing the results.  Firstly, the relatively low levels of Vitamin D in the whole cohort (both cases and controls) makes conclusions more difficult and a similar study using a wider range of values would be more beneficial.  Secondly, and possibly more importantly, no data was available in this cohort for any other potential known risk factors for MS.  Without being able to account for these, it is impossible to say for certain that the differing risk observed was due to the Vitamin D levels, rather than other genetic and environmental factors.

The abstract of this study can be found here.