Air pollution is associated with abnormal left ventricular diastolic function: a nationwide population-based study

Abstract

Background: Air pollution is a growing public health concern of global significance. Till date, few studies have explored the associations between air pollutants and cardiac imaging phenotypes. In this study, we aim to explore the association of ambient air pollution and abnormal left ventricular diastolic function (ALVDF) among a large-scale free-living population.

Methods: The participants were from a national representative large-scale cross-sectional study, i.e., the China Hypertension Survey (CHS), 2012-15. After exclusion, 25,983 participants from 14 provinces and 30 districts in China were included for the final analysis. The annual average ambient PM_2.5, PM₁₀ and NO₂ concentrations were obtained from the chemical data assimilation system (ChemDAS). The clinical evaluation of left ventricular function was conducted in the survey field which was based on echocardiography. Grading diastolic dysfunction was based on Recommendations for the evaluation of left ventricular diastolic function by echocardiography (2009).

Results: The mean age of 25,983 participants was 56.8 years, 46.5% were male, and the crude prevalence of GradeI-III ALVDF were 48.1%, 1.6% and 1.1%, respectively. The ORs (95% CI) for ALVDF in the fully adjusted model were 1.31 (1.11-1.56), 1.11 (1.01-1.21) and 1.18 (0.90-1.54) for an increase of 10 μg/m³ of PM_2.5, PM₁₀ and NO₂, respectively. And for different grades of ALVDF, elevated concentration of PM_2.5 and PM₁₀ exposures significantly increased the risk of gradeIinstead of gradeII ~ III ALVDF. There was a positive linear and "J" shape concentration-response association between annual average ambient PM_2.5 and NO₂ and the ALVDF risk assessed by the restricted cubic spline. The exposure level of most participants to PM₁₀ was less than 130 μg/m³, and the risk of ALVDF increased significantly with the concentration rise.

Conclusions: This large-scale nationwide population study demonstrated a significantly positive association between ambient PM_2.5, PM₁₀ and NO₂ with ALVDF, especially for mild ALVDF. The functional abnormality may partially explain the enhanced cardiovascular morbidity and mortality associated with air pollution, which highlights the importance of appropriate interventions to reduce ambient air pollution in China.

Keywords: Air pollution; Cardiac dysfunction; Particulate matter; Population; Risk factor.