Demographic time bomb in COPD (1990-2050): A joinpoint-APC-BAPC modeling study on diverging risk factor attributions...

Chronic obstructive pulmonary disease (COPD) is a leading global cause of morbidity and mortality, characterized by irreversible airflow limitation and progressive symptoms. Despite declining age-standardized rates (ASRs), absolute burdens are rising due to population aging and growth, particularly in low- and middle-Sociodemographic Index (SDI) regions. This study provides the first comprehensive analysis of COPD epidemiology from 1990 to 2021 using Global Burden of Disease 2021 data, integrating multimodel projections to 2050 and risk factor attribution across SDI quintiles. The study extracted COPD incidence, prevalence, mortality, and disability-adjusted life years (DALYs) from the Global Burden of Disease 2021 study (204 countries, 1990-2021). Trends were analyzed via Joinpoint regression, average annual percentage change, age-period-cohort models, and decomposition analysis (population growth/aging/epidemiological shifts). Risk factor burdens (smoking, ambient PM2.5, and household air pollution) were quantified using population attributable fractions. Bayesian age-period-cohort models projected the age-standardized incidence rate, age-standardized mortality rate, and age-standardized DALY rate to 2050. Globally, the age-standardized incidence rate, age-standardized mortality rate, and DALY rate declined (average annual percentage change: -0.05%, -1.49%, and -1.48%, respectively), while absolute cases, deaths, and DALYs increased (213.4 million cases and 1.69 million deaths in 2021). Low-/middle-SDI regions exhibited 2- to 3-fold higher ASRs than high-SDI areas. An inverted V-shaped relationship emerged between SDI and COPD burden, peaking at an SDI of 0.4 to 0.6. Smoking (38%-55% of DALYs), ambient PM2.5 (15%-25%), and household air pollution (0%-55%) dominated risk factors, with marked SDI-based heterogeneity. Projections indicate stable/declining ASRs globally to 2050, but rising absolute burdens in low-SDI nations. COPD remains a critical public health challenge, with shifting burdens from mortality to high prevalence. Targeted interventions in low-SDI regions - clean energy adoption, community spirometry screening, and culturally tailored tobacco control - are imperative to meet the United Nations 2030 noncommunicable disease mortality targets.