Short-term mediating effects of PM2.5 on climate-associated COPD severity

Huan Minh Tran; Yuan-Chien Lin; Feng-Jen Tsai; Kang-Yun Lee; Jer-Hwa Chang; Chi-Li Chung; Kian Fan Chung; Kai-Jen Chuang; Hsiao-Chi Chuang

doi:10.1016/j.scitotenv.2023.166523

Short-term mediating effects of PM_2.5 on climate-associated COPD severity

Sci Total Environ. 2023 Dec 10:903:166523. doi: 10.1016/j.scitotenv.2023.166523. Epub 2023 Aug 23.

Authors

Huan Minh Tran¹, Yuan-Chien Lin², Feng-Jen Tsai³, Kang-Yun Lee⁴, Jer-Hwa Chang⁵, Chi-Li Chung⁶, Kian Fan Chung⁷, Kai-Jen Chuang⁸, Hsiao-Chi Chuang⁹

Affiliations

¹ Ph.D. Program in Global Health and Health Security, College of Public Health, Taipei Medical University, Taipei, Taiwan; Faculty of Public Health, Da Nang University of Medical Technology and Pharmacy, Da Nang, Viet Nam. Electronic address: d537110006@tmu.edu.tw.
² Department of Civil Engineering, National Central University, Taoyuan City, Taiwan. Electronic address: yclin@ncu.edu.tw.
³ Ph.D. Program in Global Health and Health Security, College of Public Health, Taipei Medical University, Taipei, Taiwan. Electronic address: jeanfjtsai@tmu.edu.tw.
⁴ Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan. Electronic address: leekangyun@tmu.edu.tw.
⁵ School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Pulmonary Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan. Electronic address: jerhwa@tmu.edu.tw.
⁶ Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Pulmonary Medicine, Department of Internal Medicine, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan. Electronic address: clchung@tmu.edu.tw.
⁷ National Heart & Lung Institute, Imperial College London, UK. Electronic address: f.chung@imperial.ac.uk.
⁸ School of Public Health, College of Public Health, Taipei Medical University, Taipei, Taiwan; Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan. Electronic address: kjc@tmu.edu.tw.
⁹ Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan; National Heart & Lung Institute, Imperial College London, UK; Cell Physiology and Molecular Image Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan. Electronic address: chuanghc@tmu.edu.tw.

PMID: 37625725
DOI: 10.1016/j.scitotenv.2023.166523

Abstract

The impact of short-term exposure to environmental factors such as temperature, relative humidity (RH), and fine particulate matter (PM_2.5) on chronic obstructive pulmonary disease (COPD) remains unclear. The objective of this study is to investigate PM_2.5 as a mediator in the relationship between short-term variations in RH and temperature and COPD severity. A cross-sectional study was conducted on 930 COPD patients in Taiwan from 2017 to 2022. Lung function, COPD Assessment Test (CAT) score, and modified Medical Research Council (mMRC) dyspnea scale were assessed. The mean and differences in 1-day, 7-day, and 30-day individual-level exposure to ambient RH, temperature, and PM_2.5 were estimated. The associations between these factors and clinical outcomes were analyzed using linear regression models and generalized additive mixed models, adjusting for age, sex, smoking, and body mass index. In the total season, increases in RH difference were associated with increases in forced expiratory volume in 1 s (FEV₁) / forced vital capacity (FVC), while increases in temperature difference were associated with decreases in FEV₁ and FEV₁/FVC. Increases in PM_2.5 mean were associated with declines in FEV₁. In the cold season, increases in temperature mean were associated with decreases in CAT and mMRC scores, while increases in PM_2.5 mean were associated with declines in FEV₁, FVC, and FEV₁/FVC. In the warm season, increases in temperature difference were associated with decreases in FEV₁ and FEV₁/FVC, while increases in RH difference and PM_2.5 mean were associated with decreases in CAT score. PM_2.5 fully mediated the associations of temperature mean with FEV₁/FVC in the cold season. In conclusion, PM_2.5 mediates the effects of temperature and RH on clinical outcomes. Monitoring patients during low RH, extreme temperature, and high PM_2.5 levels is crucial. Capsule of findings The significance of this study is that an increase in ambient RH and temperature, as well as PM_2.5 exposure, were significantly associated with changes in lung function, and clinical symptoms in these patients. The novelty of this study is that PM_2.5 plays a mediating role in the association of RH and temperature with COPD clinical outcomes in the short term.

Keywords: COPD; Climate; Clinical outcomes; Lung function; PM(2.5).