Global epidemiology of amyotrophic lateral sclerosis: a systematic review and meta-analysis

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with the global epidemiological profile remaining incompletely understood. While previous systematic reviews existed, an updated comprehensive synthesis is needed to delineate the disease burden. METHODS: We searched PubMed, Embase, Scopus, Web of Science and Cochrane databases from inception to 18 February 2025, for studies reporting the incidence, prevalence or mortality of ALS in the general population. Pooled estimates with 95% CIs were calculated, and subgroup analyses were performed. RESULTS: Of 29 110 articles initially screened, 142 were included. Global pooled incidence was 1.65 per 100 000 person-years (95% CI 1.43 to 1.91), prevalence was 5.05 per 100 000 population (95% CI 4.26 to 5.99) and mortality was 1.26 per 100 000 person-years (95% CI 0.94 to 1.69). Both incidence rate ratio (IRR=0.74) and prevalence rate ratio (PRR=0.69) indicated significantly lower disease burden in females than in males. The burden of disease exhibited a marked age-dependent pattern, peaking at ages 70-79. Temporal trend analyses revealed a consistent increase in prevalence from 1963 to 1999 onwards, while incidence peaked in 2014-2017. Geographically, incidence and prevalence were highest in Europe, North America and Oceania and lowest in Asia and South America. The disease burden was significantly higher in high-income countries compared with both upper-middle-income and lower-middle-income countries. CONCLUSION: This systematic review provides updated global ALS burden estimates, showing variations by sex, age, time and geography and underscoring the complex interplay of genetic, environmental and socioeconomic factors, with implications for health planning, resource allocation and etiological research.