Upper Airway Microbiomes Respond to Preceding Air Pollution During Periods of Health and Respiratory Illness Events

Air pollution is higher in urban populations, is associated with asthma exacerbations, and exhibits seasonal dynamics. Very little is known about the connection between air pollution exposure and the airway microbiome, especially in childhood asthma. Nasal blow samples were collected in the MUPPITS-1 study at baseline and first respiratory illness. Nasal microbiota profiles, from 16S V4 sequencing, were paired with regional levels of pollutants including PM2.5, Nitrogen Dioxide (NO2), Carbon Monoxide (CO) and Ozone (O3) up to one-week preceding sample collection (Day -7 to Day 0). A lagged Generalized Linear Model assessed associations between pollution and nasal microbiota, where time-lagged variables were included in the same model for each pollutant. In the week preceding the baseline sample, CO exposure in the preceding days related to bacterial community composition (Lagged Generalized Linear Model; Day -1 P=0.02, Day 0 P=0.01), while NO2 (Day -4 P=0.04) and PM2.5 (Day -3 P=0.05) exposures three to four days prior to sample collection related to baseline microbiota variance. Interactions between nasal microbiota and pollution related to asthma exacerbation. In the days preceding a respiratory illness visit, several pollutants (CO, NO2, PM2.5, O3) at Day -3 and -2 exhibited a significant (P < 0.05) interactions with the nasal microbiota in models of the association of illness-associated exacerbations with pollutant concentrations and microbiota. These data suggest that nasal microbiota, in combination with pollution exposure, relates to illness-associated exacerbations in children with asthma. This may allow identification of microbiomes that prevent or predict exacerbation in the context of pollutant exposure.