Global lung cancer burden attributable to air fine particulate matter and tobacco smoke exposure: spatiotemporal patterns, sociodemographic characteristics, and transnational inequalities from 1990 to 2021.

backgroundAir fine particulate matter and tobacco smoke exposure are primary risk factors for lung cancer. However, their recent global exposure levels, attributable burden, and patterns of inequalities remain insufficiently quantified.

methodsUtilizing the Global Burden of Disease 2021 study, we analyzed exposure levels of air fine particulate matter (ambient and household) and tobacco smoke (active and secondhand) by age-standardized summary exposure value (ASEV). Age-standardized mortality rate (ASMR) and age-standardized disability-adjusted life years rate (ASDR) were used to assess their attributable lung cancer burden globally. Temporal patterns were examined using weighted average annual percentage change (WAPC). Cross-national health inequalities were evaluated with the concentration index (CI) for ASMR and slope index of inequality (SII) for ASDR.

resultsIn 2021, air fine particulate (PM2.5) exposure peaked in low socio-demographic index (SDI) countries, while tobacco exposure was highest in high-middle SDI regions. Globally, air PM2.5 contributed to 374.21 thousand (95% uncertainty interval [UI]: 236.36, 520.26) lung cancer deaths [ambient: 297.60 thousand (95% UI: 183.71, 414.74); household: 76.48 thousand (95% UI: 28.6, 187.34)], whereas tobacco exposure caused 1,238.65 thousand (95% UI: 1,075.69, 1,423.12) deaths [active smoking: 1,195.80 thousand (95% UI: 1,054.67, 1,359.22); secondhand smoke: 97.91 thousand (95% UI: 11.96, 184.91)]. High-middle SDI countries and the Southeast Asia, East Asia, and Oceania regions bore the greatest burden. The attributable burden for males exceeded that for females by approximately twofold for air PM2.5 and fivefold for tobacco exposure. The 55 + age group showed disproportionately high impacts despite lower exposure. From 1990 to 2021, the ASMR attributable to air PM2.5 and tobacco exposure changed annually by -1.32% (95% confidence interval [CI]: -1.48, -1.16) and - 0.95% (95% CI: -1.03, -0.88), respectively. The attributable ASDR also showed declining trends. Regarding translational health inequality, the air PM2.5 attributable lung cancer burden shifted from high to low SDI countries (CI: 0.05 to -0.10, SII: 31.00 to -35.50), while the tobacco-attributable burden persisted in higher SDI countries, albeit with diminishing inequalities (CI: 0.34 to 0.25, SII: 572.20 to 304.60).

conclusionsThis up-to-date study provides a comprehensive perspective on air fine particulate matter and tobacco smoke exposure's impact on lung cancer burden, highlighting its widespread nature, substantial impact, unequal distribution, and preventability. The findings call for targeted interventions and global cooperation across socioeconomic levels to reduce the overall lung cancer burden in the post-pandemic era.