MS Speaks

JAMA Neurology (June 27, 2016) contains an article by Cruz et al., "Time- and Region-Specific Season of Birth Effects in Multiple Sclerosis in the United Kingdom," which finds that MS risk looks greater among persons born in April than among those born in November, though the reasons are unclear. The study involved over 21,000 participants.

The same issue contains an editorial about the article.  Here is the first paragraph of the editorial, which is by Jennifer S. Graves, MD, and is entitled "Is Season of Birth Important for Multiple Sclerosis Risk?":

Establishing that there are gestation-related risk factors for multiple sclerosis (MS) significantly impacts our understanding of the timing of environmental risk in MS and ultimately would have a critical influence on prevention strategies. One such factor—month or season of birth—has been reported to be associated with risk of MS and other diseases, such as asthma and type 1 diabetes mellitus, as well as overall lifespan. Prior studies have demonstrated a higher risk for MS in infants born in the spring, whether in the Northern or Southern hemispheres. Recent work has questioned these associations based on unaccounted-for biases from birth patterns in the general population. Concern has centered on the concept that birth rates are not homogeneously distributed throughout the year and may vary by region or latitude within a country. Seasonality has been shown to be more prominent with higher birth rates in the spring in countries or regions farther away from the equator. Because the frequency of MS is well known to vary by latitude, these regional birth rates may cause false association of birth month and MS risk.

[Reference numbers omitted.]

The entire editorial can be seen here.

The editorial is worth reading in its entirety as it points out that it is far too soon to jump to conclusions about vitamin D.