Epidemiological Studies on Multiple Sclerosis and Allied Diseases：A Review with Special Reference to Geographical Distribution in Various Countries Including Japan

1）Epidemiological problems on multiple sclerosis were reviewed as to significance，problems in Japan, various epidemiologic statistics including hospital statistics, mortality statistics and population survey.

2）In Japan various data, hospital, mortality and morbidity statistics, support the very low prevalence of the disease, although other neurologic disorders such as motor neuron disease are similarly prevalent to the Western countries.

3）In Japan the prevalence does not increase with higher latitude. Due to small number it is not certain whether exogenous geographic climatic factors are applicable among the Japanese. However, other explanation is probably necessary.