Multiple sclerosis has a distinct geographical zonality. The inhabitants of the northern states of the USA, Canada, Russia, northern and central European Union countries, southern regions of Australia are most susceptible to disease: here disease frequency is in range of 0.04-0.05% among the population. The disease is most rare registered in regions with more sunlight - in Africa, in Asian countries, in Oceania, in Central and South America: the incidence rate in these areas is almost 10 times less.
Multiple sclerosis is 2 times more often diagnosed in women, but for men it usually has a less favorable couse. There are also noticeable differences in the racial distribution: the most affected are people of Caucasian race, the representatives of Mongoloid race are the least affected. The onset of the disease usually occurs at a young age: most diagnoses are first established for patients aged 15 to 40 years.