Global, regional, and 204 countries burden of disease attributed to secondhand smoke-related COPD, 1990-2021: A secondary data analysis of the Global Burden of Disease Study 2021.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) imposes a significant economic burden on global public health systems. This secondary data analysis aims to estimate the disease burden of COPD attributable to secondhand smoke exposure from 1990 to 2021. METHODS: Data on mortality, age-standardized mortality rate (ASMR), and age-standardized disability-adjusted life years rate (ASDR) for COPD attributable to secondhand smoke exposure were collected from the Global Burden of Disease (GBD 2021) database. The percentage changes in estimated annual percentage change, number of deaths, and number of disability-adjusted life years were calculated. The associations between ASMR and sociodemographic index (SDI), as well as between ASDR and SDI, were also investigated. The autoregressive integrated moving average time series model was used to project future trends through 2031. RESULTS: Between 1990 and 2021, the number of deaths worldwide attributable to secondhand smoke exposure leading to COPD increased. ASMR decreased from 11.36 (95% UI: 4.52-18.55) to 5.87 (95% UI: 2.29-9.72), while ASDR decreased from 234.01 (95% UI: 93.58-380.47) to 120.94 (95% UI: 47.2-197.93). In 2021, China had the highest mortality (117387.96; 95% UI: 47776.16-195915.33), while Papua New Guinea had the highest ASMR (31.63; 95% UI: 11.96-54.96) and ASDR (597.51; 95% UI: 226.75-1036.97). The decline in COPD mortality and ASDR was greater among females than among males. SDI exhibited a nonlinear association with both ASMR and ASDR, with SDI=0.42 representing the inflection point for this relationship. Furthermore, the predictive model estimates that ASMR and ASDR attributable to secondhand smoke exposure for COPD will continue declining through 2031. CONCLUSIONS: Globally, both ASMR and ASDR for COPD attributable to secondhand smoke exposure have shown a declining trend, which is projected to continue. However, the magnitude of decline and absolute disease burden vary across income-heterogeneous countries. There is an urgent need to strengthen awareness interventions targeting vulnerable populations and enforce indoor smoke-free policies to prevent further harm.