title: Clinical and demographic factors and outcome of amyotrophic lateral sclerosis in relation to population ancestral origin.
abstract: BACKGROUND
  To review how the phenotype and outcome of amyotrophic lateral sclerosis (ALS) change with variations in population ancestral origin (PAO). Knowledge of how PAO modifies ALS phenotype may provide important insight into the risk factors and pathogenic mechanisms of the disease.
  
  
  METHODS
  We performed a systematic review and meta-analysis of the literature concerning differences in phenotype and outcome of ALS that relate to PAO.
  
  
  RESULTS
  A review of 3111 records identified 78 population-based studies. The 40 that were included covered 40 geographical areas in 10 subcontinents. Around 12,700 ALS cases were considered. The results highlight the phenotypic heterogeneity of ALS at time of onset [age, sex ratio (SR), bulbar onset], age at diagnosis, occurrence of comorbidities in the first year after diagnosis, and outcome (survival). Subcontinent is a major explanatory factor for the variability of the ALS phenotype in population-based studies. Some markers of ALS phenotype were homogeneously distributed in western countries (SR, mean age at onset/diagnosis) but their distributions in other subcontinents were remarkably different. Other markers presented variations in European subcontinents (familial ALS, bulbar onset) and in other continents. As a consequence, ALS outcome strongly varied, with a median survival time from onset ranging from 24 months (Northern Europe) to 48 months (Central Asia).
  
  
  CONCLUSIONS
  This review sets the scene for a collaborative study involving a wide international consortium to investigate, using a standard methodology, the link between ancestry, environment, and ALS phenotype.
authors.affiliation: INSERM, U1094, Neuroépidémiologie Tropicale, 87000, Limoges, France.|Univ. Limoges, UMR_S 1094, Neuroépidémiologie Tropicale, Institut d'Epidémiologie Neurologique et de Neurologie Tropicale, CNRS FR 3503 GEIST, 87000, Limoges, France.|CHU Limoges, Centre d'Epidémiologie, de Biostatistique et de Méthodologie de la Recherche, 87000, Limoges, France.|Laboratorio di Malattie Neurologiche, Dipartimento di Neuroscienze, IRCCS Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.|Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari "Aldo Moro", Bari, Italy.|Unit of Neurodegenerative Diseases, Department of Clinical Research in Neurology, University of Bari "Aldo Moro", at "Pia Fondazione Cardinale G. Panico", Tricase, Lecce, Italy.
authors.forename: Benoît
authors.initials: B
authors.lastname: Marin
authors.affiliation: Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari "Aldo Moro", Bari, Italy.|Unit of Neurodegenerative Diseases, Department of Clinical Research in Neurology, University of Bari "Aldo Moro", at "Pia Fondazione Cardinale G. Panico", Tricase, Lecce, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Logroscino
authors.affiliation: INSERM, U1094, Neuroépidémiologie Tropicale, 87000, Limoges, France.|Univ. Limoges, UMR_S 1094, Neuroépidémiologie Tropicale, Institut d'Epidémiologie Neurologique et de Neurologie Tropicale, CNRS FR 3503 GEIST, 87000, Limoges, France.|CHU Limoges, Centre d'Epidémiologie, de Biostatistique et de Méthodologie de la Recherche, 87000, Limoges, France.
authors.forename: Farid
authors.initials: F
authors.lastname: Boumédiene
authors.affiliation: INSERM, U1094, Neuroépidémiologie Tropicale, 87000, Limoges, France.|CHU Limoges, Centre d'Epidémiologie, de Biostatistique et de Méthodologie de la Recherche, 87000, Limoges, France.
authors.forename: Anaïs
authors.initials: A
authors.lastname: Labrunie
authors.affiliation: INSERM, U1094, Neuroépidémiologie Tropicale, 87000, Limoges, France.|Univ. Limoges, UMR_S 1094, Neuroépidémiologie Tropicale, Institut d'Epidémiologie Neurologique et de Neurologie Tropicale, CNRS FR 3503 GEIST, 87000, Limoges, France.|Service de Neurologie, Centre Expert SLA, CHU Limoges, Limoges, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Couratier
authors.affiliation: Genetic Variability and Human Diseases, UMR 946, INSERM, Paris, France.|UMR 946, Univ Paris Diderot, Paris, France.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Babron
authors.affiliation: Genetic Variability and Human Diseases, UMR 946, INSERM, Paris, France.|UMR 946, Univ Paris Diderot, Paris, France.
authors.forename: Anne Louise
authors.initials: AL
authors.lastname: Leutenegger
authors.affiliation: INSERM, U1094, Neuroépidémiologie Tropicale, 87000, Limoges, France.|Univ. Limoges, UMR_S 1094, Neuroépidémiologie Tropicale, Institut d'Epidémiologie Neurologique et de Neurologie Tropicale, CNRS FR 3503 GEIST, 87000, Limoges, France.|CHU Limoges, Centre d'Epidémiologie, de Biostatistique et de Méthodologie de la Recherche, 87000, Limoges, France.
authors.forename: Pierre Marie
authors.initials: PM
authors.lastname: Preux
authors.affiliation: Laboratorio di Malattie Neurologiche, Dipartimento di Neuroscienze, IRCCS Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. ettore.beghi@marionegri.it.
authors.forename: Ettore
authors.initials: E
authors.lastname: Beghi
mesh_terms: D017668:Age of Onset; D000690:Amyotrophic Lateral Sclerosis / Q000208:ethnology / Q000235:genetics* / Q000401:mortality; D018450:Disease Progression; D005006:Ethnicity; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D010641:Phenotype; D011379:Prognosis; D044469:Racial Groups; D012042:Registries; D012737:Sex Factors; D015996:Survival Rate; D016896:Treatment Outcome
keywords: Amyotrophic lateral sclerosis; Continental population groups; Epidemiology; Ethnic groups; Phenotype