Ultraviolet B (UVB) exposure contributes to multiple sclerosis (MS) severity in temperate zones outside the 40o parallels.
Why this matters
There appears to be a complex interplay between genetic and environmental factors for both development of MS and symptomology. Latitude is one factor consistently associated with development of MS. Less is known about its role in severity of symptoms.
As there is wide variety in the severity of MS symptoms between diagnosed individuals, understanding why this occurs may, in the future, help to optimize tailored management of MS.