| Title: | Preexisting Multimorbidity Predicts Greater Mortality Risks Related to Long-Term PM2.5 Exposure |
| Journal: | - |
| Published: | 1 Sep 2024 |
| DOI: | https://doi.org/10.2139/ssrn.4955300 |
Publication 13354
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Abstract
Background: Long-term health risk assessments related to ambient fine particulate matter (PM2.5) exposure have been more limited to general population but not towards individuals suffering from multimorbidity. While both multimorbidity and PM2.5 are independently linked to elevated mortality risk, their combined effects and interactions remain practically unexplored.Methods: A cross-cohort analysis was undertaken on data from 3 population-based prospective cohorts of UK Biobank, the Taiwan MJ Cohort, and the Taiwan Biobank, initially enrolling 869038 adults aged ≥18 years followed up during 2005-2022. Multimorbidity, defined as the co-occurrence of two or more chronic diseases, was identified at baseline surveys through a list of nine common chronic conditions. Cox proportional hazards models were utilized to quantify the associations of long-term PM2.5exposure with all-cause, cardiovascular, and respiratory mortality among individuals with and without multimorbidity. Joint effects and interactions between baseline multimorbidity and PM2.5 level on the additive and multiplicative scales were examined in associations with mortality outcomes. Risk differences of PM2.5-induced mortality were analyzed stratified by number of chronic conditions and multimorbidity patterns. Subgroup and sensitivity analyses were carried out to evaluate the consistency of the findings.Findings: Among 713119 eligible participants for primary analysis, 65490 prevalent cases of multimorbidity were identified at baseline, and a total of 32771 death events were recorded over a median follow-up of 12.2 years. Compared to individuals without multimorbidity, associations of PM2.5 exposure with all-cause and cardiovascular mortality were more prominent among multimorbidity individuals (P <0.05 for heterogeneity). Specifically, multivariable-adjusted hazard ratios (HRs) of cardiovascular mortality linked with a 5-μg/m³ increment in PM2.5 were 1.427 (95% confidence interval [CI]: 1.316-1.549) among multimorbidity individuals and 1.151 (95% CI: 1.089-1.216) for individuals without multimorbidity. Our analysis unveiled a significant additive interaction between PM2.5 level and preexisting multimorbidity status, yielding estimated attributable proportions of 11.7%-17.8% and excess risks of 31.1%-72.6% for different mortality outcomes. Joint association analysis indicated that, compared to those without chronic disease and under lower tertile of PM2.5 exposure (HR = 1), participants with ≥3 chronic conditions and under upper tertile of PM2.5 exposure had the highest mortality risks, with an estimated HR of 6.94 (95% CI: 6.07-7.94) for all-cause mortality, 9.29 (95% CI: 7.00-12.31) for cardiovascular mortality, and 24.75 (95% CI: 14.14-43.31) for respiratory mortality, respectively. Individuals with cardiometabolic and arthritis multimorbidity were at greater PM2.5-associated risks of both all-cause and cardiovascular mortality. Sex subgroup and sensitivity analyses consistently produced similar results.Interpretation: This large-scale multicohort analysis demonstrated markedly stronger associations between PM2.5 levels and risks of all-cause and cardiovascular mortality in multimorbidity populations compared to those without multimorbidity. PM2.5exposure and preexisting multimorbidity showed synergistic effects in triggering mortality events, wherein the joint risks were intensified with elevated PM2.5 levels and an increased number of chronic conditions.Funding: Dr. Yunquan Zhang was supported by the Chunhui Program Collaborative Research Project of the Ministry of Education (Grant No. HZKY20220336), Wuhan Knowledge Innovation Project (Grant No. 2023020201020410), and "The 14th Five Year Plan" Hubei Provincial Advantaged Characteristic Disciplines (Groups) Project of Wuhan University of Science and Technology (grant number 2023C0102).Declaration of Interest: No competing personal relationships or financial interests have been disclosed by the authors that could have affected the work reported hereEthical Approval: The UKB, TW-MJ, and TWB cohorts were approved by the institutional review boards in UK and Chinese Taiwan, and all recruited participants provided written informed consent.</p>
5 Authors
- Ziqing Tang
- Po-Wen Ku
- Yang Xia
- Li-Jung Chen
- Yunquan Zhang
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