TY - JOUR T1 - Worldwide prevalence of neuromyelitis optica spectrum disorders JF - Journal of Neurology, Neurosurgery & Psychiatry JO - J Neurol Neurosurg Psychiatry SP - 555 LP - 556 DO - 10.1136/jnnp-2017-317566 VL - 89 IS - 6 AU - Masahiro Mori AU - Satoshi Kuwabara AU - Friedemann Paul Y1 - 2018/06/01 UR - http://jnnp.bmj.com/content/89/6/555.abstract N2 - The prevalence of multiple sclerosis (MS) has been reported from many countries in the world, and prominent geographical differences among regions are well known: over 100 per 100 000 in European and North American populations vs 0–20 per 100 000 in Asian populations. These differences suggest that genetic factors are important in the development of MS. Moreover, it is also known that higher latitude is associated with higher prevalence of MS. The latitude gradient for MS risk is thought to be related to low sun exposure, possibly because this is associated with low serum levels of vitamin D, which has an immunomodulatory effect.In contrast, data on the prevalence of neuromyelitis optica (NMO) and its wider disease spectrum, … ER -