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.