Сочетание жары и дыма от пожаров повышает риск сердечно-сосудистой смерти на 14%

Compound exposure to heat waves and substantial fire-sourced air pollution is associated with an increased cardiovascular mortality risk compared with exposure to either hazard alone, according to study findings published in the Journal of the American College of Cardiology. The time-series study evaluated short-term associations between compound landscape fire-sourced air pollution–heat wave events and cardiovascular mortality. Individual-level mortality data were obtained from a mortality database for Australia, Brazil, Canada, Chile, Mexico, and Thailand over various periods between 2000 to 2019. The primary outcome was total cardiovascular mortality. Daily concentrations of landscape fire-sourced particulate matter with aerodynamic diameter of 2.5 μm or less (PM2.5) and ozone were estimated globally. The short-term associations between compound exposure to heat waves and fire-sourced air pollution and daily cardiovascular mortality were estimated in a 2-stage analytical framework. The first stage involved a quasi-Poisson generalized linear model for each location to account for overdispersion in daily death counts. The primary exposure was a categorical variable for mutually exclusive daily exposure states: nonexposed (reference), fire-sourced air pollution-only, heat wave-only, and compound heat wave-fire-sourced air pollution exposure. For the second stage, location-specific estimates were pooled in a random-effects meta-analysis for country-level and overall associations. These findings suggested that analyses treating heat waves and SFAP [fire-sourced air pollution] as independent hazards may underestimate short-term cardiovascular mortality risk during compound exposure events. Among 755 locations, 5.9 million cardiovascular disease (CVD) deaths occurred, with 54.4 deaths per 100,000 population for ischemic heart disease (IHD), 43.3 deaths per 100,000 population for stroke, and 12.0 deaths per 100,000 population for heart failure (HF). In most countries, fire-sourced air pollution episode duration and landscape fire-sourced pollutant concentrations were generally higher in heat wave periods compared with nonheat wave periods. Pooled results showed that compound exposure was associated with an 11.5% increase in overall cardiovascular mortality (relative risk [RR], 1.115; 95% CI, 1.100-1.130), which was higher compared with risk for heat wave-only exposure (RR, 1.083; 95% CI, 1.074-1.091) and risk for fire-sourced air pollution-only exposure (RR, 1.014; 95% CI, 1.008-1.021). A positive additive interaction was observed, with a relative excess risk due to interaction (RERI) of 0.018 (95% CI, 0.002-0.035). Regarding cardiovascular mortality during compound exposure days, 1.598% (95% CI, 0.181-3.129) was attributable to interaction separate from the independent effects of heat waves and fire-sourced air pollution. The synergy index (SI) was 1.184 (95% CI, 1.019-1.398). Compound exposure in men was associated with a 10.5% increase in cardiovascular mortality (RR, 1.105; 95% CI, 1.088-1.122), with an additive interaction observed (RERI, 0.021 [95% CI, 0.002-0.042]; SI, 1.247 [95% CI, 1.021-1.561]). The corresponding risk for women was slightly higher (RR, 1.143; 95% CI, 1.124-1.163), and had similar interaction estimates (RERI, 0.022 [95% CI, 0.001-0.045]; SI, 1.184 [95% CI, 1.008-1.414]). Similar patterns occurred for cause-specific cardiovascular mortality. Compound exposure was associated with an RR of 1.097 for IHD (95% CI, 1.075-1.119), with a corresponding RERI of 0.029 (95% CI, 0.005-0.056; SI, 1.432; 95% CI, 1.068-2.013). HF had the strongest additive interaction, in which compound exposure was associated with an RR of 1.245 (95% CI, 1.191-1.301), as well as a higher RERI (0.096; 95% CI, 0.040-0.161). In addition, 7.731% (95% CI, 3.293%-12.488%) of HF mortality during compound exposure days was attributable to interaction (SI, 1.648; 95% CI, 1.228-2.334). Increased RR of heat wave-only and compound exposure generally occurred with more strict heat wave definitions that combined increased temperature thresholds with longer durations. Limitations of the study include potential residual confounding, and landscape fire-sourced air pollution was estimated rather than directly measured. Also, substantial heterogeneity was observed among the countries and population subgroups. “These findings suggested that analyses treating heat waves and SFAP [fire-sourced air pollution] as independent hazards may underestimate short-term cardiovascular mortality risk during compound exposure events,” the study authors wrote. This article originally appeared on The Cardiology Advisor