Oral microbiome and associations with chemical exposure, asthma and lung function

Background: Previous studies indicated that lung health might be affected by both antibacterial chemicals and poor oral health. Aims and objective: Describe association between oral microbiome and paraben exposure, asthma and lung function. Methods: Interview data, lung function, gingival fluid and urine were collected from 288 adults (48% females, median age: 28 yrs) from the RHINESSA study in Bergen, Norway. Differential abundance in the gingival microbiome (Illumina sequencing) across dose groups (quartiles) for urine biomarkers of paraben exposure was evaluated using the Analysis of composition of microbiomes (ANCOM) methodology with 5% FDR, adjusting for gender and asthma status. Association between microbial diversity and lung function was assessed by linear regression with adjustment for height, weight, age, smoking, and asthma medication. Results: Propyl- and methyl-parabens were detected in 94% subjects, with 62 times higher concentration in women than men. With increasing exposure to parabens, Enterobacter spp in the gingival fluid decreased in a dose-response manner, whereas Fretibacterium spp increased. FEV 1 and FVC increased with increasing microbiome diversity in women; FEV 1 with b (95% CI) =0.13 (0.02, 0.24) and FVC with b=0.15 (95% CI: 0.01, 0.28) per unit increase in Shannon index. No association was seen for men. Conclusions: Lung function increased with increasing oral microbial diversity in women only. Paraben exposure was associated with bacteria linked to poor oral health (Fretibacterium), independent of gender and asthma status (including asthma medication). Exposure to antibacterial chemicals may modify the association between oral microbiome and lung health.