Background: The incidence and prevalence of multiple sclerosis (MS) varies considerably around the world. No previous study has performed a comprehensive review examining the incidence and prevalence of MS across the Americas. The purpose of this study was to systematically review and assess the quality of studies estimating the incidence and/or prevalence of MS in North, Central and South American regions. Methods: A comprehensive literature search was performed using MEDLINE and EMBASE from January 1985 to January 2011. Search terms included ‘multiple sclerosis’, ‘incidence’, ‘prevalence’ and ‘epidemiology’. Only full-text articles published in English or French were included. Study quality was assessed using an assessment tool based on recognized guidelines and designed specifically for this study. Results: A total of 3,925 studies were initially identified, with 31 meeting the inclusion criteria. The majority of studies examined North American regions (n = 25). Heterogeneity was high among all studies, even when stratified by country. Only half of the studies reported standardized rates, making comparisons difficult. Quality scores ranged from 3/8 to 8/8. Conclusion: This review highlights the gaps that still exist in the epidemiological knowledge of MS in the Americas, and the inconsistencies in methodologies and quality among the published studies. There is a need for future studies of MS prevalence and incidence to include uniform case definitions, employ comparable methods of ascertainment, report standardized results, and be performed on a national level. Other factors such as sex distribution, ethnic make-up and population lifestyle habits should also be considered.

1.
Noseworthy J, Lucchinetti C, Rodriguez M, Weinshenker B: Multiple sclerosis. N Engl J Med 2000;343:938–952.
2.
Pugliatti M, Rosati G, Carton H: The epidemiology of multiple sclerosis in Europe. Eur J Neurol 2006;13:700–722.
3.
Canadian Institute of Health Information: The Burden of Neurological Diseases, Disorders and Injuries in Canada. Ottawa, Canadian Institute of Health, 2007.
4.
Poppe A, Wolfson C, Zhu B: Prevalence of multiple sclerosis in Canada: a systematic review. Can J Neurol Sci 2008;35:593–601.
5.
Boyle M: Guidelines for evaluating prevalence studies. Evid Based Ment Health 1998;1:37–39.
6.
Poser C, Paty D, Scheinberg L: New diagnostic criteria for multiple sclerosis: guidelines for research protocols. Ann Neurol 1983;13:227–231.
7.
Gracia F, Castillo L, Benzadon A, et al: Prevalence and incidence of multiple sclerosis in Panama (2000–2005). Neuroepidemiology 2009;32:287–293.
8.
Toro J, Sarmiento O, Diaz del Castillo A, et al: Prevalence of multiple sclerosis in Bogota, Colombia. Neuroepidemiology 2007;28:33–38.
9.
Beck C, Metz L, Svenson L, Patten S: Regional variation of multiple sclerosis prevalence in Canada. Mult Scler 2005;11:516–519.
10.
Pryse-Phillips W: The incidence and prevalence of multiple sclerosis in Newfoundland and Labrador, 1960–1984. Ann Neurol 1986;20:323–328.
11.
Hader W, Yee I: Incidence and prevalence of multiple sclerosis in Saskatoon, Saskatchewan. Neurology 2007;69:1224–1229.
12.
Warren S, Svenson L, Warren K, Metz L, Patten S, Schopflocher D: Incidence of multiple sclerosis among First Nations people in Alberta, Canada. Neuroepidemiology 2007;28:21–27.
13.
Warren S, Svenson L, Warren K: Contribution of incidence to increasing prevalence of multiple sclerosis in Alberta, Canada. Mult Scler 2008;14:872–879.
14.
Mayr W, Pittock S, McClelland R, Jorgenson N, Noseworthy J, Rodriguez M: Incidence and prevalence of multiple sclerosis in Olmsted County, Minnesota, 1985–2000. Neurology 2003;61:1373–1377.
15.
Noonan C, Williamson D, Henry J, et al: The prevalence of multiple sclerosis in 3 US communities. Prev Chronic Dis 2010;7:A12.
16.
Cabre P, Signate A, Olindo S, et al: Role of return migration in the emergence of multiple sclerosis in the French West Indies. Brain 2005;128:2899–2910.
17.
Melcon M, Gold L, Carra A, et al: Argentine Patagonia: prevalence and clinical features of multiple sclerosis. Mult Scler 2008;14:656–662.
18.
Compston A, Confavreux C, Lassmann H, et al: The story of multiple sclerosis; in Compston A, Confavreux C, Lassmann H, et al (eds): McAlpine’s Multiple Sclerosis, ed 4. London, Elsevier, 2005.
19.
Kurtzke J, Beebe G, Norman JJ: Epidemiology of multiple sclerosis in US veterans. 1. Race, sex, and geographic distribution. Neurology 1979;29:1228–1235.
20.
Alonso A, Hernan M: Temporal trends in the incidence of multiple sclerosis: a systematic review. Neurology 2008;71:129–135.
21.
Risco J, Maldonado H, Luna L, et al: Latitudinal prevalence gradient of multiple sclerosis in Latin America. Mult Scler 2011;17:1055–1059.
22.
Zivadinov R, Iona L, Monti-Bragadin L, et al: The use of standardized incidence and prevalence rates in epidemiological studies on multiple sclerosis. Neuroepidemiology 2003;22:64–74.
23.
Koch-Henriksen N, Sorensen PS: The changing demographic pattern of multiple sclerosis epidemiology. Lancet Neurology 2010;9:520–532.
24.
Simpson SJ, Blizzard L, Otahal P, Van der Mei I, Taylor B: Latitude is significantly associated with the prevalence of multiple sclerosis: a meta-analysis. J Neurol Neurosurg Psychiatry 2011;82:1132–1141.
25.
Williamson D, Henry J, Schiffer R, Wagner L: Prevalence of multiple sclerosis in 19 Texas counties, 1998–2000. J Environ Health 2007;69:41–45.
26.
Svenson L, Warren S, Warren K, Metz L, Patten S, Schopflocher D: Prevalence of multiple sclerosis in First Nations people of Alberta. Can J Neurol Sci 2007;34:175–180.
27.
Mirsattari S, Johnston J, McKenna R, et al: Aboriginals with multiple sclerosis HLA types and predominance of neuromyelitis optica. Neurology 2001;56:317–323.
28.
Hader W, Feasby T, Noseworthy J, Rice G: Multiple sclerosis in Canadian native people. Neurology 1985;35(suppl 1):300.
29.
Chancellor A, Addidle M, Dawson K: Multiple sclerosis is more prevalent in northern New Zealand than previously reported. Intern Med J 2003;33:79–83.
30.
Orton S-M, Herrera B, Yee I, et al: Sex ratio of multiple sclerosis in Canada: a longitudinal study. Lancet Neurol 2006;5:932–936.
31.
Marrie R, Cutter G, Tyry T, Hadjimichael O, Campagnolo D, Vollmer T: Changes in the ascertainment of multiple sclerosis. Neurology 2005;65:1066–1070.
32.
Inglese M: Multiple sclerosis: new insights and trends. AJNR 2006;27:954–957.
33.
Wallin M, Page W, Kurtzke J: Multiple sclerosis in US veterans of the Vietnam era and later military service: race, sex, and geography. Ann Neurol 2004;55:65–71.
34.
Svenson L, Woodhead S, Platt G: Regional variations in the prevalence rates of multiple sclerosis in the province of Alberta, Canada. Neuroepidemiology 1994;13:8–13.
35.
Wynn D, Rodriguez M, O’Fallon W, Kurland L: A reappraisal of the epidemiology of multiple sclerosis in Olmsted County, Minnesota. Neurology 1990;40:780–786.
36.
Culpepper W, Ehrmantraut M, Wallin M, Flannery K, Bradham D: Veterans Health Administration multiple sclerosis surveillance registry: the problem of case-finding from administrative databases. J Rehabil Res Dev 2006;43:17–24.
37.
Cowen J, Sjostrom B, Doughty A, Schiffer R: Case-finding for MS prevalence studies in small communities requires a community-based approach. Neuroepidemiology 2007;28:246–252.
38.
Marrie R, Yu N, Blanchard J, Leung S, Elliot L: The rising prevalence and changing age distribution of multiple sclerosis in Manitoba. Neurology 2010;74:465–471.
39.
Tu K, Campbell N, Chen Z-L, Cauch-Dudek K, McAlister F: Accuracy of administrative databases in identifying patients with hypertension. Open Med 2007;1:E18–E26.
40.
Hux J, Ivis F, Flintoft V, Bica A: Diabetes in Ontario – determination of prevalence and incidence using a validated administrative data algorithm. Diabetes Care 2002;25:512–516.
41.
Wirehn A-B, Karlsson M, Carstensen J: Estimating disease prevalence using a population-based administrative healthcare database. Scand J Public Health 2007;35:424–431.
42.
Lange J, Chang Y-F, LaPorte R: Use of the capture-recapture method for epidemiological studies determining prevalence. Acta Neurol Scand 2004;109:79–80.
43.
Nelson L, Anderson D: Case finding for epidemiological surveys of multiple sclerosis in United States communities. Mult Scler 1995;1:48–55.
44.
de Sa J, Alcade-Cabero E, Almazan-Isla J, Sempere A, de Pedro-Cuesta J: Capture-recapture as a potentially useful procedure for assessing prevalence of multiple sclerosis: methodologic exercise using Portuguese data. Neuroepidemiology 2012;39:209–216.
45.
The Lancet Neurology: Making EUReMS count for people with multiple sclerosis. Lancet Neurol 2011;10:865.
46.
Galluccio F, Walker U, Nihtyanova S, et al: Registries in systemic sclerosis: a worldwide experience. Rheumatology 2011;50:60–68.
47.
Warren S, Warren K: Prevalence of multiple sclerosis in Barrhead County, Alberta, Canada. Can J Neurol Sci 1992;19:72–75.
48.
Warren S, Warren K: Prevalence, incidence, and characteristics of multiple sclerosis in Westlock County, Alberta, Canada. Neurology 1993;43:1760–1763.
49.
Klein G, Rose M, Seland T: A prevalence study of multiple sclerosis in the Crowsnest Pass region of Southern Alberta. Can J Neurol Sci 1994;21:262–265.
50.
Sloka J, Pryse-Phillips W, Stefanelle M: Incidence and prevalence of multiple sclerosis in Newfoundland and Labrador. Can J Neurol Sci 2005;32:37–42.
51.
Helmick C, Wrigley J, Zack M, et al: Multiple sclerosis in Key West, Florida. Am J Epidemiol 1989;130:935–949.
52.
Hopkins R, Indian R, Pinnow E, Conomy J: Multiple sclerosis in Galion, Ohio: prevalence and results of a case-control study. Neuroepidemiology 1991;10:192–199.
53.
Neuberger J, Lynch S, Sutton M, Hall S, Feng C, Schmidt W: Prevalence of multiple sclerosis in a residential area bordering an oil refinery. Neurology 2004;63:1796–1802.
54.
Turabelidze G, Schootman M, Zhu B, et al: Multiple sclerosis prevalence and possible lead exposure. J Neurol Sci 2008;269:158–162.
55.
Cabre P, Heinzlef O, Merle H, et al: MS and neuromyelitis optica in Martinique (French West Indies). Neurology 2001;56:507–514.
56.
Callegaro D, Amaro De Lolio C, Radvany J, Tilbery C, Mendonca R, Paiva Melo A: Prevalence of multiple sclerosis in the city of São Paulo, Brazil, in 1990. Neuroepidemiology 1992;11:11–14.
57.
Callegaro D, Goldbaum M, Morais L, et al: The prevalence of multiple sclerosis in the city of São Paulo, Brazil. Acta Neurol Scand 2001;104:208–213.
58.
Cristiano E, Patrucco L, Rojas J, et al: Prevalence of multiple sclerosis in Buenos Aires, Argentina using the capture-recapture method. Eur J Neurol 2009;16:183–187.
59.
Cabre P: Environmental changes and epidemiology of multiple sclerosis in the French West Indies. J Neurol Sci 2009;286:58–61.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.