title: Global epidemiology of amyotrophic lateral sclerosis: a systematic review of the published literature.
abstract: BACKGROUND
  Amyotrophic lateral sclerosis (ALS) is relatively rare, yet the economic and social burden is substantial. Having accurate incidence and prevalence estimates would facilitate efficient allocation of healthcare resources.
  
  
  OBJECTIVE
  To provide a comprehensive and critical review of the epidemiological literature on ALS.
  
  
  METHODS
  MEDLINE and EMBASE (1995-2011) databases of population-based studies on ALS incidence and prevalence reporting quantitative data were analyzed. Data extracted included study location and time, design and data sources, case ascertainment methods and incidence and/or prevalence rates. Medians and interquartile ranges (IQRs) were calculated, and ALS case estimates were derived using 2010 population estimates.
  
  
  RESULTS
  In all, 37 articles met the inclusion criteria. In Europe, the median incidence rate (/100,000 population) was 2.08 (IQR 1.47-2.43), corresponding to an estimated 15,355 (10,852-17,938) cases. Median prevalence (/100,000 population) was 5.40 (IQR 4.06-7.89), or 39,863 (29,971-58,244) prevalent cases.
  
  
  CONCLUSIONS
  Disparity in rates among ALS incidence and prevalence studies may be due to differences in study design or true variations in population demographics such as age and geography, including environmental factors and genetic predisposition. Additional large-scale studies that use standardized case ascertainment methods are needed to more accurately assess the true global burden of ALS.
authors.affiliation: Rita Levi Montalcini Department of Neuroscience, University of Turin, Turin, Italy. adriano.chio@unito.it
authors.forename: A
authors.initials: A
authors.lastname: Chiò
authors.forename: G
authors.initials: G
authors.lastname: Logroscino
authors.forename: B J
authors.initials: BJ
authors.lastname: Traynor
authors.forename: J
authors.initials: J
authors.lastname: Collins
authors.forename: J C
authors.initials: JC
authors.lastname: Simeone
authors.forename: L A
authors.initials: LA
authors.lastname: Goldstein
authors.forename: L A
authors.initials: LA
authors.lastname: White
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000453:epidemiology*; D014943:Global Health / Q000639:trends; D006801:Humans