The joint associations of ambient air pollutants and weather factors with mortality: Evidence from a national time-stratified case-crossover study in China

Qijiong Zhu; Min Yu; Guoxia Bai; Chunliang Zhou; Ruilin Meng; Biao Huang; Weiwei Gong; Haoming Zhang; Ruying Hu; Zhulin Hou; Yize Xiao; Donghui Jin; Mingfang Qin; Jianxiong Hu; Jianpeng Xiao; Guanhao He; Lifeng Lin; Xiaofeng Liang; Yanfang Guo; Tao Liu; Wenjun Ma

doi:10.1016/j.scitotenv.2023.168129

The joint associations of ambient air pollutants and weather factors with mortality: Evidence from a national time-stratified case-crossover study in China

Sci Total Environ. 2023 Oct 27:168129. doi: 10.1016/j.scitotenv.2023.168129. Online ahead of print.

Authors

Qijiong Zhu¹, Min Yu², Guoxia Bai³, Chunliang Zhou⁴, Ruilin Meng⁵, Biao Huang⁶, Weiwei Gong², Haoming Zhang⁷, Ruying Hu², Zhulin Hou⁶, Yize Xiao⁷, Donghui Jin⁴, Mingfang Qin⁷, Jianxiong Hu⁸, Jianpeng Xiao⁸, Guanhao He¹, Lifeng Lin⁵, Xiaofeng Liang¹, Yanfang Guo⁹, Tao Liu¹⁰, Wenjun Ma¹

Affiliations

¹ Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou 510632, China; China Greater Bay Area Research Center of Environmental Health, School of Medicine, Jinan University, Guangzhou 510632, China; Disease Control and Prevention Institute of Jinan University, Jinan University, Guangzhou 510632, China.
² Zhejiang Center for Disease Control and Prevention, Hangzhou, Zhejiang 310051, China.
³ Institute of Non-communicable Diseases Prevention and Control, Tibet Center for Disease Control and Prevention, Lhasa 850000, China.
⁴ Department of Environment and Health, Hunan Provincial Center for Disease Control and Prevention, Changsha 450001, China.
⁵ Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China.
⁶ Health Hazard Factors Control Department, Jilin Provincial Center for Disease Control and Prevention, Changchun 130062, China.
⁷ Yunnan Center for Disease Control and Prevention, Kunming 650022, China.
⁸ Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China.
⁹ Bao'an District Hospital for Chronic Diseases Prevention and Cure, Shenzhen 518101, China. Electronic address: [email protected].
¹⁰ Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou 510632, China; China Greater Bay Area Research Center of Environmental Health, School of Medicine, Jinan University, Guangzhou 510632, China; Disease Control and Prevention Institute of Jinan University, Jinan University, Guangzhou 510632, China. Electronic address: [email protected].

PMID: 39491184
DOI: 10.1016/j.scitotenv.2023.168129

Abstract

Background: People in daily life are usually exposed to multiple environmental factors, but few studies have evaluated the joint health impacts of ambient air pollutants and weather factors.

Objectives: To investigate the joint associations of short-term exposures to ambient air pollutants and weather factors with mortality and estimate the mortality burden attributable to these multiple environmental exposures in China.

Methods: We collected individual death information from six provinces (Guangdong, Yunnan, Hunan, Zhejiang, Tibet and Jilin) in China during 2013 to 2018, and applied a time-stratified case-crossover study design to estimate the joint associations of air pollutants [PM_2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm), O₃ (ozone), NO₂ (nitrogen dioxide), SO₂ (sulfur dioxide), and CO (carbon monoxide)] and weather factors (temperature and relative humidity) with mortality. Air pollutant concentrations on the case day and control days were assessed using a random forest model, and the corresponding temperature and relative humidity data were assessed using a thin plate smoothing model. Excess risks (ER) of exposure to air pollutants and weather factors were estimated using Cox proportional regression models and the attributable fraction (AF) was calculated.

Results: A total of 6,685,146 deaths were enrolled in this study. The overall AF of total mortality attributed to air pollutants (lag03 days) and weather factors (lag021 days) was 16.65 % (95%CI: 16.43 %, 16.87 %), in which the joint AFs attributable to air pollutants and weather factors were 5.31 % (95%CI: 5.08 %, 5.53 %) and 11.34 % (95%CI: 11.12 %, 11.56 %) respectively, and temperature contributed 56 % in the joint effects. Stratified analyses showed greater AFs in females (21.32 %) than in males (14.61 %), and in the elderly (>100 years, 42.34 %) than in young people (21-30 years, 7.67 %). The AFs of mortality from cardiovascular diseases, respiratory diseases, and pneumonia attributed to the joint exposures were 22.72 %, 24.82 % and 33.03 %, respectively.

Discussion: This study provides the joint associations of short-term exposures to both air pollutants and weather factors with mortality risk in China, which has important implications in comprehensively assessing the health impacts of environmental exposures, and taking actions to protect human health.

Keywords: Air pollution; Environmental exposures; Joint association; Mortality burden; Temperature.