Long-Term Exposure to Air Pollution and Markers of Inflammation, Coagulation and Endothelial Activation: a Repeat Measures Analysis in the Multi-Ethnic Study of Atherosclerosis (MESA)

Abstract

Air pollution is associated with cardiovascular disease (CVD) and systemic inflammation is posited to mediate this effect. Animal, experimental and epidemiologic studies suggest increases in short-term air pollution cause an inflammatory response. Much of the past literature has focused on the association between short-term air pollution exposure and markers of inflammation and coagulation. We assessed both the association between long- and short-term exposure to air pollution and markers of inflammation, coagulation and endothelial activation. We studied participants from the Multi-Ethnic Study of Atherosclerosis (MESA) with repeat measures of serum C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen, D-dimer, soluble E-selectin and soluble Intercellular Adhesion Molecule-1 (sICAM-1). We estimated associations of these markers with long-term ambient fine particulate matter (PM2.5), individual-level ambient PM2.5 (integrating indoor concentrations and time-location data), oxides of nitrogen (NOX), nitrogen dioxide (NO) and black carbon averaged over the year prior to blood draw. Short-term concentrations of PM2.5 reflected day of blood draw, prior day, and moving average of prior 2, 3, 4, and 5 day periods. CRP, IL-6 and D-Dimer were log-transformed. A random effects model was used to account for within-person clustering. After controlling for confounders, a 5 µg/m3 increase in long-term ambient PM2.5 was associated with a 5.53% higher IL-6 level (95% CI: 1.83, 9.36) and a 40 ppb increase in long-term NOx was associated with 7.07% higher level in D-dimer (95% CI: 1.62, 12.83). CRP, E-selectin and sICAM-1 showed little association with long-term air pollution and associations between short-term ambient PM2.5 and blood markers was largely null. These data are consistent with the hypothesis that associations between long-term exposure to air pollution are related to inflammation and fibrinolysis.