Urban Air Pollution, Systemic Inflammation, and Sub-Clinical Atherosclerosis in Ecuadorian Children

Exposure to fine particulate matter (PM2.5) and other urban air pollutants is linked with increased cardiovascular morbidity and mortality risk in adults. However, little is known about the effect of PM2.5 exposure on child health. To investigate the hypothesis that chronic childhood exposure to urban PM2.5 promotes oxidative stress, systemic inflammation, and vascular remodeling, we conducted an epidemiologic study in 300 schoolchildren (7-12 yrs), residing in a major urban center (Quito) with distinct PM gradient zones. Data were collected on PM and other air pollutants from central air monitors, inside air monitors, and an exposure questionnaire. Other data were collected on child and household characteristics, medical history, current health, anthropometry, diet, blood glucose and lipids, and systemic inflammation and endothelium activation biomarkers. Carotid intima-media thickness (cIMT) was measured by ultrasound. Preliminary results showed that systemic inflammation, measured by IL-6, was significantly increased (mean log-scale difference= 0.49 ± 0.07; P< 0.001) among children residing in higher compared to lower PM2.5 exposure zones (23.5 ìg/m3 vs. 16.4 ìg/m3). Higher exposure zone children exhibited greater endothelium activation, measured by higher mean E-selectin (0.72 ± 0.07; P< 0.001) and ICAM (0.17 ± 0.04; P < 0.001). They also had small but significantly increased cIMT compared to children in the lower exposure zone (0.02 ± 0.01; P=0.032). These findings suggest that early childhood exposure to high PM2.5 promotes systemic inflammation and vascular remodeling. They are important since small but progressive increases in arterial wall thickness and stiffness can lead to earlier cardiovascular morbidity and mortality.