Air pollution and retinal vessel diameter and blood pressure in school-aged children in a region impacted by residential biomass burning

Little is known about the early-life cardiovascular health impacts of fine particulate air pollution (PM 2.5 ) and oxidant gases. A repeated-measures panel study was used to evaluate associations between outdoor PM 2.5 and the combined oxidant capacity of O 3 and NO 2 (using a redox-weighted average, O x ) and retinal vessel diameter and blood pressure in children living in a region impacted by residential biomass burning. A median of 6 retinal vessel and blood pressure measurements were collected from 64 children (ages 4–12 years), for a total of 344 retinal measurements and 432 blood pressure measurements. Linear mixed-effect models were used to estimate associations between PM 2.5 or O x (same-day, 3-day, 7-day, and 21-day means) and retinal vessel diameter and blood pressure. Interactions between PM 2.5 and O x were also examined. O x was inversely associated with retinal arteriolar diameter; the strongest association was observed for 7-day mean exposures, where each 10 ppb increase in O x was associated with a 2.63 μm (95% CI − 4.63, − 0.63) decrease in arteriolar diameter. Moreover, O x modified associations between PM 2.5 and arteriolar diameter, with weak inverse associations observed between PM 2.5 and arteriolar diameter only at higher concentrations of O x . Our results suggest that outdoor air pollution impacts the retinal microvasculature of children and interactions between PM 2.5 and O x may play an important role in determining the magnitude and direction of these associations.