The Effects of Ambient Air Pollutants on Changes in Cardiac Structure and Function

The effects of air pollutants on cardiac structure and function preceding the clinical diagnosis of heart failure are not well understood.

The objective of the study was to determine if ambient pollutant concentrations are associated with longitudinal changes in cardiac structure and function.

Measures of cardiac structure and function were serially assessed by echocardiogram at visits 1 (2008-2011) and 2 (2015-2018), respectively, with a median follow-up of 4.3 years (IQR: 4.0-4.4 years). Outdoor air pollution concentrations at residence were estimated from spatio-temporal models, as mean concentrations the year prior to each visit. We determined longitudinal relationships between air pollution and each echocardiographic measure, adjusted for baseline and time-varying covariates.

Echocardiographic data were available on 1,630 individuals; mean age was 55.3 years at visit 1. Per IQR of pollutant, higher mean residential concentrations of particulate matter air pollution <2.5 µm in aerodynamic diameter (particulate matter 2.5 [PM_2.5]) and traffic-related air pollutant gas (nitrogen dioxide) were associated with a 0.52% (95% CI: 0.20-0.83) and 0.12% (95% CI: 0.03-0.20) increase in global longitudinal strain, respectively. Higher PM_2.5 and nitrogen dioxide were associated with decreased left atrial volume index: -1.39 (95% CI: -2.25 to -0.54) and -0.94 (95% CI: -1.63 to -0.26) respectively. PM_2.5 was associated with a decrease in left ventricular ejection fraction of -1.05% per year (95% CI: -1.73 to -0.37) and increase in relative wall thickness by 0.12 (95% CI: 0.05-0.19) unit.

Our findings suggest that common air pollutant exposures are associated with longitudinal preclinical adverse changes in cardiac structure and function.