Editing Multiple sclerosis (section)

== Epidemiology ==
{{Update|section|date=July 2022}}
[[File:Multiple sclerosis world map-Deaths per million persons-WHO2012.svg|thumb|left|upright=1.3|Deaths from multiple sclerosis per million persons in 2012 {{Div col|small=yes|colwidth=10em}}{{legend|#ffff20|0}}{{legend|#ffc020|1}}{{legend|#f08015|2}}{{legend|#e06815|3–5}}{{legend|#d85010|6–12}}{{legend|#d02010|13–25}}{{div col end}}]]

MS is the most common autoimmune disorder of the central nervous system.<ref name="pmid24746689" /> The latest estimation of the total number of people with MS was 2.8&nbsp;million globally, with a [[prevalence]] of 36 per 100,000 people. Moreover, prevalence varies widely in different regions around the world.<ref name="Lane2022" /> In Africa, there are five people per 100,000 diagnosed with MS, compared to South East Asia where the prevalence is nine per 100,000, 112 per 100,000 in the Americas, and 133 per 100,000 in Europe.<ref>{{Cite web | work = Multiple Sclerosis International Federation |date=September 2020 |title=Atlas of MS |url=https://www.msif.org/wp-content/uploads/2020/12/Atlas-3rd-Edition-Epidemiology-report-EN-updated-30-9-20.pdf}}</ref> Nearly one million people in the United States had MS in 2022.<ref name="McGinley2021">{{cite journal |vauthors=McGinley MP, Goldschmidt CH, Rae-Grant AD |title=Diagnosis and Treatment of Multiple Sclerosis: A Review |journal=JAMA |volume=325 |issue=8 |pages=765–779 |date=February 2021 |pmid=33620411 |doi=10.1001/jama.2020.26858|s2cid=232019589 }}</ref>

Increasing rates of MS may be explained simply by better diagnosis.<ref name=Milo2010 /> Studies on populational and [[#Geography|geographical patterns]] have been common<ref name="pmid8269393">{{cite journal | vauthors = Kurtzke JF | title = Epidemiologic evidence for multiple sclerosis as an infection | journal = Clinical Microbiology Reviews | volume = 6 | issue = 4 | pages = 382–427 | date = October 1993 | pmid = 8269393 | pmc = 358295 | doi = 10.1128/CMR.6.4.382 }}</ref> and have led to a number of theories about the cause.<ref name="Ascherio_2007"/><ref name="pmid15556803">{{cite journal | vauthors = Marrie RA | title = Environmental risk factors in multiple sclerosis aetiology | journal = The Lancet. Neurology | volume = 3 | issue = 12 | pages = 709–18 | date = December 2004 | pmid = 15556803 | doi = 10.1016/S1474-4422(04)00933-0 | s2cid = 175786 }}</ref><ref name="pmid17492755">{{cite journal | vauthors = Ascherio A, Munger KL | title = Environmental risk factors for multiple sclerosis. Part II: Noninfectious factors | journal = Annals of Neurology | volume = 61 | issue = 6 | pages = 504–13 | date = June 2007 | pmid = 17492755 | doi = 10.1002/ana.21141 | s2cid = 36999504 | doi-access = free }}</ref>

MS usually appears in adults in their late twenties or early thirties but it can rarely start in childhood and after 50 years of age.<ref name=Milo2010 /><ref name=Atlas2008 /> The primary progressive subtype is more common in people in their fifties.<ref name="pmid17884680" /> Similarly to many autoimmune disorders, the disease is more common in women, and the trend may be increasing.<ref name="pmid1897097722"/><ref name="pmid18606967">{{cite journal | vauthors = Alonso A, Hernán MA | title = Temporal trends in the incidence of multiple sclerosis: a systematic review | journal = Neurology | volume = 71 | issue = 2 | pages = 129–135 | date = July 2008 | pmid = 18606967 | pmc = 4109189 | doi = 10.1212/01.wnl.0000316802.35974.34 }}</ref> As of 2020, globally it is about two times more common in women than in men, and the ratio of women to men with MS is as high as 4:1 in some countries.<ref>{{cite journal | vauthors = Walton C, King R, Rechtman L, Kaye W, Leray E, Marrie RA, Robertson N, La Rocca N, Uitdehaag B, van der Mei I, Wallin M, Helme A, Angood Napier C, Rijke N, Baneke P | title = Rising prevalence of multiple sclerosis worldwide: Insights from the Atlas of MS, third edition | journal = Multiple Sclerosis | volume = 26 | issue = 14 | pages = 1816–1821 | date = December 2020 | pmid = 33174475 | pmc = 7720355 | doi = 10.1177/1352458520970841 }}</ref> In children, it is even more common in females than males,<ref name="pmid1897097722"/> while in people over fifty, it affects males and females almost equally.<ref name="pmid17884680" />