Global, regional, and national burden of cardiovascular diseases attributable to secondhand smoke, 1990–2021

Objective: This study assessed the global burden and trends of cardiovascular diseases attributable to secondhand smoke (CVD-SHS) from 1990 to 2021. Methods: The global burden of disease (GBD) database was utilized to analyze estimated annual percentage change (EAPC), age-standardized mortality rates (ASMR), age-standardized DALY rates (ASDR), disability-adjusted life years (DALYs), and deaths due to CVD-SHS. Subsequently, further analysis was conducted by region, age group, sex, and socio-demographic index (SDI). Finally, Spearman correlation analyses were used to assess the correlation of ASDR and ASMR with SDI. Results: From 1990 to 2021, global CVD-SHS deaths and DALYs increased by 34.5 and 23.1%, respectively, while ASMR and ASDR decreased by 41.8 and 42.0%. In 2021, CVD-SHS deaths totaled 694,692 (ASMR 8.31/100,000), with DALYs at 16,674,552 (ASDR 194.59/100,000). Regionally, the highest ASDR and ASMR were observed in low-middle and middle SDI regions, with minimal reductions in low SDI regions. Correlation analysis indicated that ASMR and ASDR, as well as their EAPCs, were negatively correlated with SDI. Moreover, CVD-SHS burden was higher in males and older age groups, predominantly affecting those aged 35 and above in lower SDI regions, and those aged 65 and above in high SDI regions. Conclusion: From 1990 to 2021, the global, regional, and national burden of CVD-SHS showed a paradoxical trend: while ASMR and ASDR declined, the absolute number of deaths and DALYs continued to rise. The burden and its growth rate were negatively correlated with SDI, with the highest impacts observed in low- and middle-SDI regions, males, and older populations. Moreover, stroke-SHS showed a stronger negative correlation with SDI than IHD-SHS, suggesting subtype-specific disparities. These findings highlight the persistent and uneven burden of CVD-SHS worldwide and underscore the need for targeted, region- and disease-specific prevention strategies.