Background:
Air pollution contributes to cardiovascular morbidity, including heart failure. Exposure to pollutants has been associated with hypertension and inflammation, which contribute to cardiac remodeling. Few studies have investigated long-term air pollution concentrations and measures of cardiac structure, and no large longitudinal analyses have investigated this association.
Hypothesis:
Long-term air pollution concentrations are associated with magnetic resonance imaging-derived measures of left ventricular structure and function.
Methods:
In the Multi-Ethnic Study of Atherosclerosis (MESA), we investigated cross-sectional and longitudinal associations between modeled fine particulate matter (PM2.5), oxides of nitrogen (NOX) and ozone (O3) concentrations and left ventricular mass index (LVMI), mass to volume ratio, ejection fraction, and circumferential strain by cardiac magnetic resonance imaging (CMR) at two time points roughly 10 years apart. Multivariable linear regression was used to estimate the association between pollutants and both cross-sectional and longitudinal CMR measures.
Results:
At MESA Exam 1 (2000-2002), 4,825 participants in our cross-sectional analysis sample had a mean age of 61 years (standard deviation: 10), 53% were women, 40% were white, 13% were Chinese-American, 25% were African-American, and 21% were Hispanic. At Exam 1, Higher concentrations of PM2.5 and NOX in the year prior to Exam 1 were associated with higher LVMI at Exam 1 (1.6% per 5ug/m3 higher PM2.5, 95% CI: 0.3, 2.9; 1.8% per 40 parts per billion [ppb] NOX, 95% CI: 0.3, 3.3) and higher O3 was associated with lower LVMI (-3.5% per 10ppb, 95% CI: -6.0, -1.0). In longitudinal analyses, higher NOX was associated with a worsening of LV circumferential strain (-0.87% per 40ppb, 95% CI: -1.69, -0.05).
Conclusions:
Our study offers mixed evidence of a cross-sectional association between higher PM2.5 and NOx concentrations and greater LVMI. We also found associations between greater O3 concentration and lower cross-sectional LVMI, though this association may be confounded by other pollutants. These findings suggest a role for NOX, PM2.5, and O3 in cardiac remodeling. Additional work is needed to clarify that role and better understand the biological underpinnings of these associations.
Estimating long-term average household air pollution concentrations from repeated short-term measurements in the presence of seasonal trends and crossover
