[Epidemiology of multiple sclerosis and neuromyelitis optica].

Multiple sclerosis (MS) is thought to be multifactorial diseases caused some environmental factor acts on the genetic background. The number of patients with MS has been increasing in the world, especially in young female. The prevalence of MS is more about high latitudes, and there is the same tendency in Japan. On the other hand, there is no difference in the prevalence of neuromyelitis optica (NMO) by race and latitude. The national epidemiological survey in 2012 showed that the patient number of NMO/NMO spectrum disorder is estimated to be about 4,400 people in Japan. There was no obvious regional difference in prevalence of patients.