Objectives Exercise may increase the inhaled amount of air pollutants and exacerbate the adverse health effects. We investigated the combined effects of chronic exposure to fine particulate matter with an aerodynamic diameter less than 2.5 µm (PM2.5) and habitual exercise on C reactive protein (CRP), a sensitive marker of inflammation.
Methods We selected 40 209 Taiwanese adults who joined a standard medical screening programme between 2001 and 2016. The PM2.5 exposure was estimated at each participant’s address using a satellite-based spatiotemporal model. Information on habitual exercise was collected using a standard self-administered questionnaire. Mixed-effects linear regression models were used to investigate the associations of CRP with PM2.5 and exercise. An interaction term of PM2.5 and exercise was introduced in the models to test the modifying effects.
Results A greater amount of habitual exercise was associated with a decreased level of CRP, while a higher concentration of PM2.5 exposure was associated with an increased level of CRP. The inverse associations of habitual exercise with CRP were not modified by chronic exposure to PM2.5. The participants in the group with a low level of exercise and a high level of PM2.5 exposure exhibited a 19.1% higher level of CRP than those in the group with a high level of exercise and a low level of PM2.5 exposure (95% CI: 13.7% to 24.8%; p<0.001). The longitudinal and sensitivity analyses yielded similar results.
Conclusions Increased levels of exercise and reduced exposure levels of PM2.5 are associated with a lower CRP level. Habitual exercise reduces CRP level regardless of the levels of chronic PM2.5 exposure. Our results support that habitual exercise is a safe approach for reducing systemic inflammation to improve cardiovascular health even for people residing in relatively polluted areas.
- particulate matter
- longitudinal studies
Data availability statement
Data are available upon reasonable request.
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Contributors XQL conceived of and designed the study. L-yC, AKHL, CL, TT and XQL acquired the data. YQZ performed data analysis. YQZ and XQL interpreted the data. YQZ wrote the first draft of the manuscript. All authors critically revised the manuscript and contributed to the development of the manuscript for important intellectual content. XQL acquired the funding. L-yC, AKHL, TT and XQL supervised this study. XQL is the guarantor responsible for the overall content. All authors gave final approval and agreed to be accountable for all aspects of the work ensuring integrity and accuracy.
Funding This work was supported by the RGC-General Research Fund of University Grant Committee of Hong Kong (14603019) and Guangdong Basic and Applied Basic Research Foundation (2019A1515011697). YQZ is supported by the PhD Studentship of the Chinese University of Hong Kong. CG is supported by the RGC Postdoctoral Fellowship Scheme of the University Grants Committee of Hong Kong. YB is in part supported by the Faculty Postdoctoral Fellowship Scheme of the Faculty of Medicine of the Chinese University of Hong Kong. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Disclaimer Any interpretation or conclusion related to this manuscript does not represent the views of MJ Health Research Foundation.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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