The Nasal Microbiome and Associations With Environmental Exposures and Respiratory Health.

BACKGROUND The nasal microbiome is directly in contact with the external environment and may play a role in respiratory health. This study aimed to evaluate the association of the nasal microbiome with air pollutants, meteorological conditions, and respiratory health in adolescents. METHODS We analyzed the nasal microbiome in 416 adolescents from the Project Viva cohort (mean age 13 years and 52% female). We tested for the association of alpha diversity, nasotypes, and bacterial genera abundance with environmental exposures from the past 2 days to the past year (PM2.5, NO2, O3, temperature, humidity, residential greenness) and respiratory outcomes (asthma, hay fever, wheezing, IgE, aeroallergen sensitization, FeNO, lung function) through regression models adjusted for confounders and corrected using a false discovery rate (FDR) < 5%. RESULTS Bacterial diversity was positively associated with hay fever and short-term exposure to NO2, while it was negatively correlated with temperature (FDR < 0.05). Adolescents whose nasal microbiome was dominated by Moraxella were exposed in the past week to lower O3 levels (ORs: 0.73-0.76) and higher temperature and humidity (ORs: 1.19-1.26). Staphylococcus dominance was positively associated with aeroallergen sensitization compared to Propionibacterium dominance (OR: 4.48, FDR = 0.03). Thirteen and eight bacterial genera abundance were associated with short-to-medium-term exposures (PM2.5, NO2, temperature) and respiratory outcomes (hay fever, wheezing, IgE, FeNO, lung function) (FDR < 0.05). Staphylococcus, Corynebacterium, Pelomonas, Lactococcus, Lachnospiraceae (unclassified), and Faecalibacterium abundance were associated with both environmental exposures and respiratory traits. CONCLUSIONS Nasal microbiome diversity was associated with hay fever, NO2, and temperature exposure. Multiple short-to-medium-term environmental exposures and respiratory outcomes were associated with nasotypes and bacterial genera abundance in adolescents.