MS ita ce mafi yawan cututtukan autoimmune na tsarin juyayi na tsakiya. A shekara ta 2010, yawan mutanen da ke fama da MS sun kasance miliyan 2<unk>2.5 (kimanin 30 a kowace 100,000) a duniya, tare da yawan bambancin bambancin a yankuna daban-daban. An kiyasta cewa ya haifar da mutuwar mutane 18,000 a wannan shekara. A Afirka, yawanci ba su da ƙasa da 0.5 a kowace 100,000, yayin da suke 2.8 a kowace 100,000 a kudu maso gabashin Asiya, 8.3 a kowace 100,000 a Amurka, da 80 a kowace 100,000 a Turai. Yawanci ya wuce 200 a kowace 100,000 a wasu al'ummomi na Arewacin Turai. Yawan sababbin lokuta da ke tasowa a kowace shekara kusan 2.5 ne a kowace 100,000. Rate na MS suna da alama suna ƙaruwa; wannan, duk da haka, yana iya zama mafi kyau ta hanyar ganewar asali. Nazarin kan yawan jama'a da yanayin ƙasa sun kasance na kowa kuma sun haifar da yawancin ra'ayoyi game da MS.
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