Wildfire-related PM2.5 and cardiovascular mortality: A difference-in-differences analysis in Brazil
Yuan Gao, Wenzhong Huang, Pei Yu, Rongbin Xu, Danijela Gašević, Xu Yue, Micheline de Sousa Zanotti Stagliorio Coêlho, Paulo Hilário Nascimento Saldiva, Yuming Guo, Shanshan Li
Abstract
Brazil has experienced unprecedented wildfires recently. We aimed to investigate the association of wildfire-related fine particulate matter (PM2.5) exposure with cause-specific cardiovascular mortality, and to estimate the attributable mortality burden. Exposure to wildfire-related PM2.5 was defined as exposure to annual mean wildfire-related PM2.5 concentrations in the 1-year prior to death. The variant difference-in-differences method was employed to explore the wildfire-related PM2.5-cardiovascular mortality association. We found that, in Brazil, compared with the population in the first quartile (Q1: ≤1.82 μg/m3) of wildfire-related PM2.5 exposure, those in the fourth quartile (Q4: 4.22–17.12 μg/m3) of wildfire-related PM2.5 exposure had a 2.2% (RR: 1.022, 95% CI: 1.013–1.032) higher risk for total cardiovascular mortality, 3.1% (RR: 1.031, 95% CI: 1.014–1.048) for ischaemic heart disease mortality, and 2.0% (RR: 1.020, 95% CI: 1.002–1.038) for stroke mortality. From 2010 to 2018, an estimation of 35,847 (95% CI: 22,424–49,177) cardiovascular deaths, representing 17.77 (95% CI: 11.12–24.38) per 100,000 population, were attributable to wildfire-related PM2.5 exposure. Targeted health promotion strategies should be developed for local governments to protect the public from the risk of wildfire-related cardiovascular premature deaths.