Ambient PM2.5, ozone and mortality in Chinese older adults: A nationwide cohort analysis (2005-2018)

Yunquan Zhang; Zhouxin Yin; Shaojie Li; Junfeng Jim Zhang; Haitong Zhe Sun; Keyang Liu; Kokoro Shirai; Kejia Hu; Chengxuan Qiu; Xiaoyun Liu; Yachen Li; Yi Zeng; Yao Yao

doi:10.1016/j.jhazmat.2023.131539

Ambient PM_2.5, ozone and mortality in Chinese older adults: A nationwide cohort analysis (2005-2018)

J Hazard Mater. 2023 Jul 15:454:131539. doi: 10.1016/j.jhazmat.2023.131539. Epub 2023 Apr 28.

Authors

Yunquan Zhang¹, Zhouxin Yin², Shaojie Li³, Junfeng Jim Zhang⁴, Haitong Zhe Sun⁵, Keyang Liu⁶, Kokoro Shirai⁶, Kejia Hu⁷, Chengxuan Qiu⁸, Xiaoyun Liu³, Yachen Li¹, Yi Zeng⁹, Yao Yao¹⁰

Affiliations

¹ Institute of Social Development and Health Management, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan 430065, China.
² Institute of Social Development and Health Management, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan 430065, China; School of Public Health and Emergency Management, Southern University of Science and Technology, Shenzhen 518055, China.
³ China Center for Health Development Studies, Peking University, Beijing, China.
⁴ Nicholas School of the Environment and Duke Global Health Institute, Duke University, Durham, NC, USA.
⁵ Centre for Atmospheric Science, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK.
⁶ Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita Shi, Osaka, Japan.
⁷ Institute of Big Data in Health Science, School of Public Health, Zhejiang University, Hangzhou 310058, China.
⁸ Aging Research Center, Karolinska Institutet, Widerströmska Huset, SE-171 65 Solna, Sweden.
⁹ Center for Healthy Aging and Development Studies, National School of Development, Peking University, Beijing, China; Center for the Study of Aging and Human Development and Geriatrics Division, Medical School of Duke University, Durham, NC, US. Electronic address: zengyi@nsd.pku.edu.cn.
¹⁰ China Center for Health Development Studies, Peking University, Beijing, China; Center for Healthy Aging and Development Studies, National School of Development, Peking University, Beijing, China. Electronic address: yao.yao@bjmu.edu.cn.

PMID: 37149946
DOI: 10.1016/j.jhazmat.2023.131539

Abstract

Background: Cohort evidence linking long-term survival with exposure to multiple air pollutants (e.g., fine particulate matter [PM_2.5] and ozone) was extensively sparse in low- and middle-income countries, especially among older adults. This study aimed to investigate potential associations of long-term exposures to PM_2.5 and ozone with all-cause mortality in Chinese older adults.

Methods: A dynamic nationwide prospective cohort comprising 20,352 adults aged ≥65 years were enrolled from the Chinese Longitudinal Healthy Longevity Study and followed up through 2005-2018. Participants' annual exposures to warm-season ozone and year-round PM_2.5 were assigned using satellite-derived spatiotemporal estimates. A directed acyclic graph (DAG) was developed to identify confounding variables. Associations of annual mean exposures to PM_2.5 and ozone with mortality were evaluated using single- and two-pollutant Cox proportional hazards models, adjusting for time-dependent individual risk factors and ambient temperature.

Results: During 100 thousand person-years of follow-up (median: 3.6 years), a total of 14,313 death events occurred. The participants were averagely aged 87.1 years at baseline and exposed to a wide range of annual average concentrations of warm-season maximum 8-hour ozone (mean, 54.4 ppb; range, 23.3-81.6 ppb) and year-round PM_2.5 (mean, 65.5 μg/m³; range, 10.1-162.9 μg/m³). Approximately linear concentration-response relationship was identified for ozone, whereas significant increases in PM_2.5-associated mortality risks were observed only when concentrations were above 60 μg/m³. Rises of 10 ppb in ozone and 10 µg/m³ in PM_2.5 above 60 µg/m³ were associated with increases in all-cause mortality of 13.2% (95% confidence interval [CI]: 10.2-16.2%) and 6.2% (95% CI: 4.6-7.7%) in DAG-based single-pollutant model, and of 9.7% (95% CI: 6.6-13.0%) and 5.3% (95% CI: 3.7-6.9%) in DAG-based two-pollutant model, respectively. We detected significant effect modification by temperature in associations of mortality with ozone (P <0.001 for interaction), suggesting greater ozone-related risks among participants in warmer locations.

Conclusions: This study provided longitudinal evidence that long-term exposure to ambient PM_2.5 and ozone significantly and independently contributed to elevated risks of all-cause mortality among older adults in China.

Keywords: CLHLS; Cohort; Fine particulate matter; Mortality; Older adults; Ozone.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Aged
Air Pollutants* / analysis
Air Pollution* / adverse effects
Air Pollution* / analysis
Cohort Studies
East Asian People
Environmental Exposure / analysis
Humans
Ozone* / analysis
Ozone* / toxicity
Particulate Matter / analysis
Prospective Studies

Substances

Ozone
Air Pollutants
Particulate Matter

Grants and funding

P01 AG031719/AG/NIA NIH HHS/United States