title: Epidemiology of amyotrophic lateral sclerosis: A review of literature.
abstract: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of motor neurons, resulting in worsening weakness of voluntary muscles until death occurs from respiratory failure. The incidence of ALS in European populations is two to three people per year per 100,000 of the general population. In Europe, crude prevalences range from 1.1/100,000 population in Yugoslavia to 8.2/100,000 in the Faroe Islands. Major advances have been made in our understanding of the genetic causes of ALS, whereas the contribution of environmental factors has been more difficult to assess and large-scale studies have not yet revealed a replicable, definitive environmental risk factor. The only established risk factors to date are older age, male gender and a family history of ALS. Median survival time from onset to death is usually 3 years from the first appearance of symptoms. Older age and bulbar onset are consistently reported to have poorer outcomes. However, there are conflicting data regarding gender, diagnostic delay and El Escorial criteria. The rate of symptom progression has been revealed to be an independent prognostic factor. Psychosocial factors and impaired cognitive function are negatively related to ALS outcome, while nutritional status and respiratory function are also related to ALS prognosis. The effect of enteral nutrition on survival is still unclear, although noninvasive positive pressure ventilation (NIPPV) has been found to improve survival. These findings have relevant implications for the design of future trials.
authors.affiliation: Centre de compétence SLA-fédération Tours-Limoges, CHU de Limoges, 2, avenue Martin-Luther-King, 87000 Limoges, France; Inserm UMR1094, neuroépidémiologie tropicale, université de Limoges, 2, rue du Dr.-Marcland, 87025 Limoges cedex, France. Electronic address: philippe.couratier@unilim.fr.
authors.forename: P
authors.initials: P
authors.lastname: Couratier
authors.affiliation: Centre de compétence SLA-fédération Tours-Limoges, CHU de Tours, 37044 Tours cedex 9, France.
authors.forename: P
authors.initials: P
authors.lastname: Corcia
authors.affiliation: Centre de compétence SLA-fédération Tours-Limoges, CHU de Limoges, 2, avenue Martin-Luther-King, 87000 Limoges, France.
authors.forename: G
authors.initials: G
authors.lastname: Lautrette
authors.affiliation: Centre de compétence SLA-fédération Tours-Limoges, CHU de Limoges, 2, avenue Martin-Luther-King, 87000 Limoges, France.
authors.forename: M
authors.initials: M
authors.lastname: Nicol
authors.affiliation: Inserm UMR1094, neuroépidémiologie tropicale, université de Limoges, 2, rue du Dr.-Marcland, 87025 Limoges cedex, France.
authors.forename: P-M
authors.initials: PM
authors.lastname: Preux
authors.affiliation: Inserm UMR1094, neuroépidémiologie tropicale, université de Limoges, 2, rue du Dr.-Marcland, 87025 Limoges cedex, France.
authors.forename: B
authors.initials: B
authors.lastname: Marin
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D015995:Prevalence; D011379:Prognosis; D012307:Risk Factors
keywords: Amyotrophic lateral sclerosis; Incidence; Prevalence; Prognostic factors; Risk factors; Survival