Supplementary Material for: Trends in Neglected Adolescent and Young adults Neurological Diseases: A systematic analysis from the GBD study 2021

Introduction and objectives: Adolescent neurological disorders remain a leading cause of the global disease burden. This study aims to provide an updated assessment and insights into the burden trends from 1990 to 2021.
Methods: We calculated the incidence, prevalence, mortality, and disability-adjusted life years (DALYs) for common 10 prevalent neurological diseases in adolescents and young adults globally from 1990 to 2021. Data were presented by total numbers, sex, age, year, location, risk factors, Socio-Demographic Index (SDI), and expressed in counts and rates.
Results: In 2021, migraine (592.8 million, 95% UI 47.6–1445.1), idiopathic epilepsy (204.8 million, 95% UI 152.8–279.5), and stroke (116.1 million, 95% UI 104.2–126.9) ranked as the top three neurological disorders globally in terms of DALYs. From 1990 to 2021, the absolute number of DALYs and deaths due to common neurological disorders significantly increased, although the age-standardized mortality rate slightly declined. Most diseases burden increased with age, with a higher prevalence in females than in males. Furthermore, significant variations were observed between different diseases and regions, and the age-standardized DALY rates for most neurological disorders showed a significant positive correlation with the country's SDI value.
Conclusion: Neurological disorders ranked second in global adolescent and young adults’ DALYs and remained a key mortality driver. Persistent absolute burden despite declining age-standardized rates urges prioritized prevention policies and care strategies amid population growth.
Keywords: Neurological disorders; Global burden; Adolescence; Disability-adjusted life years;