Airborne Microbial Signatures of Sleep Apnea Risk: Enrichment of Human-Associated and Loss of Environmental Taxa.

Sleep disorders such as obstructive sleep apnea (OSA) may be influenced by environmental exposures, yet the contribution of indoor microbial communities is not well understood. In this study, we examined whether the composition and load of airborne bacteria in bedrooms were associated with the Multivariable Apnea Prediction (MAP) index, a validated indicator of OSA risk. Bedroom air was sampled using electrostatic dust fall collectors in five Nordic centres participating in ECRHS III. Dust was analysed for bacterial load, endotoxin levels, and microbial composition using qPCR, LAL assay, and 16S rRNA sequencing. Associations between microbial exposures and MAP index were assessed using linear regression and categorical MAP cutoffs (≥ 0.5 and ≥ 0.7) adjusting for environmental factors. Bacterial community composition differed significantly between MAP groups, and participants with MAP ≥ 0.7 showed higher bacterial loads. However, alpha diversity and endotoxin levels did not vary by MAP category. A total of 35 bacterial genera were associated with MAP scores; taxa enriched in individuals with higher MAP values were primarily anaerobic and human-associated, whereas negatively associated genera were mostly aerobic and environmental. These findings suggest that the bedroom microbiome may carry a distinct microbial signature related to elevated OSA risk, potentially reflecting or contributing to sleep-disordered breathing.