Global, regional, and national burden of Early-onset Parkinson's disease: A comprehensive analysis and forecast,...

Early-onset Parkinson's disease (EOPD), defined as Parkinson's disease with onset between ages 21 and 50 years, profoundly impairs young individuals' productivity and mental health, imposing substantial economic and familial burdens. However, comprehensive global epidemiological data remain limited. This study aimed to assess the worldwide burden, key drivers, and projected trends of EOPD.

Using Global Burden of Disease Study 2021 data, we examined incidence, prevalence, deaths, disability-adjusted life years (DALYs), and age-standardised rates(ASRs) for EOPD from 1990 to 2021, stratified by sex, age, region, country, and socio-demographic index (SDI). Temporal trends were evaluated with estimated annual percentage changes (EAPC); SDI associations via Spearman's correlation; inequalities via slope index of inequality(SII) and concentration index(CI); drivers via decomposition analysis; and future projections via Bayesian age-period-cohort(BAPC) models with integrated nested Laplace approximation.

From 1990 to 2021, the global burden of EOPD increased substantially: in 2021, incident cases reached 81,047 (95% UI: 48,162-122,328), prevalent cases 483,872 (95% UI: 328,862-682,509), deaths 2,246 (95% UI: 1,995-2,496), and DALYs 180,325 (95% UI: 145,990-225,031)-representing 2.9-, 2.5-, 1.7-, and 1.9-fold increases from 1990, respectively. ASIR (EAPC 1.42%, 95% CI: 1.26-1.58) and ASPR (EAPC 1.09%, 95% CI: 1.02-1.16) increased; ASMR declined (EAPC - 0.42%, 95% CI: -0.45 to - 0.39), driven largely by middle- and high-middle-SDI regions; ASDR remained stable. Males exhibited higher burden, particularly for deaths and DALYs. Burden was stable in patients aged ≤ 34 years; absolute numbers peaked in middle-SDI regions, East Asia, and South Asia, with the highest ASRs in middle- and high-middle-SDI regions and Andean Latin America. Socioeconomic inequities persisted, with modest widening for incidence and prevalence. Decomposition attributed rises in morbidity primarily to epidemiological changes and population growth, and rises in mortality and DALYs to population growth and ageing, with marked SDI heterogeneity. Projections to 2036 forecast continued absolute increases, stabilising incidence and prevalence rates, and declining mortality and DALY rates.

The global burden of EOPD continues to rise, accompanied by notable spatial and demographic disparities. Drivers of burden changes vary significantly across regions and are closely associated with the SDI. Targeted policy interventions and resource allocation are required to address these challenges effectively.