BACKGROUND: Evidence on the potential interactive effects of heat and ambient air pollution on cause-specific mortality is inconclusive and limited to selected locations. OBJECTIVES: We investigated the effects of heat on cardiovascular and respiratory mortality and its modification by air pollution during summer months (six consecutive hottest months) in 482 locations across 24 countries. METHODS: Location-specific daily death counts and exposure data (e.g., particulate matter with diameters ≤ 2.5 µm [PM2.5]) were obtained from 2000 to 2018. We used location-specific confounder-adjusted Quasi-Poisson regression with a tensor product between air temperature and the air pollutant. We extracted heat effects at low, medium, and high levels of pollutants, defined as the 5th, 50th, and 95th percentile of the location-specific pollutant concentrations. Country-specific and overall estimates were derived using a random-effects multilevel meta-analytical model. RESULTS: Heat was associated with increased cardiorespiratory mortality. Moreover, the heat effects were modified by elevated levels of all air pollutants in most locations, with stronger effects for respiratory than cardiovascular mortality. For example, the percent increase in respiratory mortality per increase in the 2-day average summer temperature from the 75th to the 99th percentile was 7.7% (95% Confidence Interval [CI] 7.6-7.7), 11.3% (95%CI 11.2-11.3), and 14.3% (95% CI 14.1-14.5) at low, medium, and high levels of PM2.5, respectively. Similarly, cardiovascular mortality increased by 1.6 (95%CI 1.5-1.6), 5.1 (95%CI 5.1-5.2), and 8.7 (95%CI 8.7-8.8) at low, medium, and high levels of O3, respectively. DISCUSSION: We observed considerable modification of the heat effects on cardiovascular and respiratory mortality by elevated levels of air pollutants. Therefore, mitigation measures following the new WHO Air Quality Guidelines are crucial to enhance better health and promote sustainable development.

Center for Environmental and Respiratory Health Research University of Oulu Oulu Finland

Department of Air Pollution and Noise Norwegian Institute of Public Health Oslo Norway

Department of Environmental Health Harvard T H Chan School of Public Health Boston MA USA

Department of Environmental Health Instituto Nacional de Saúde Dr Ricardo Jorge Porto Portugal

Department of Environmental Health National Institute of Public Health Cuernavaca Morelos Mexico

Department of Environmental Health Rollins School of Public Health Emory University Atlanta USA

Department of Environmental Health School of Public Health Fudan University Shanghai China

Department of Environmental Health University of São Paulo São Paulo Brazil

Department of Epidemiology and Preventive Medicine School of Public Health and Preventive Medicine Monash University Melbourne Australia

Department of Epidemiology Lazio Regional Health Service ASL Roma 1 Rome Italy

Department of Family Medicine and Public Health University of Tartu Tartu Estonia

Department of Geography Geoinformatics and Meteorology University of Pretoria Pretoria South Africa

Department of Global Health Policy Graduate School of Medicine The University of Tokyo Tokyo Japan

Department of Hygiene Epidemiology and Medical Statistics Medical School National and Kapodistrian University of Athens Greece

Department of Public Health and Clinical Medicine Umeå University Sweden

Department of Public Health Environments and Society London School of Hygiene and Tropical Medicine London United Kingdom

Department of Statistics and Computational Research Universitat de València València Spain

Department of Statistics Computer Science and Applications G Parenti University of Florence Florence Italy

Environmental and Occupational Medicine and Institute of Occupational Medicine and Industrial Hygiene National Taiwan University and NTU Hospital Taipei Taiwan

Estonian Environmental Research Centre Tallinn Estonia

Graduate School of Public Health Seoul National University Seoul Republic of Korea

Institute of Atmospheric Physics Czech Academy of Sciences Prague Czech Republic Faculty of Environmental Sciences Czech University of Life Sciences Prague Czech Republic

Institute of Environmental Assessment and Water Research Barcelona Spain

Institute of Epidemiology Helmholtz Munich German Research Center for Environmental Health Neuherberg Germany

Institute of Epidemiology Helmholtz Munich German Research Center for Environmental Health Neuherberg Germany; Institute for Medical Information Processing Biometry and Epidemiology IBE Pettenkofer School of Public Health LMU Munich Munich Germany

Institute of Social and Preventive Medicine University of Bern Bern Switzerland

National Institute of Environmental Health Science National Health Research Institutes Zhunan Taiwan

Santé Publique France Department of Environmental Health French National Public Health Agency Saint Maurice France

School of Biomedical Convergence Engineering Pusan National University Yangsan South Korea

School of Epidemiology and Public Health Faculty of Medicine University of Ottawa Ottawa Canada and Environmental Health Science and Research Bureau Health Canada Ottawa Canada

School of Forestry and Environmental Studies Yale University New Haven CT USA

School of Tropical Medicine and Global Health Nagasaki University Nagasaki Japan

Swiss Tropical and Public Health Institute Basel Switzerland

Citace poskytuje Crossref.org

Joint effect of heat and air pollution on mortality in 620 cities of 36 countries