Host and lifestyle factors associated with the anterior nares’ microbiome diversity and composition: a cross-sectional analysis based on the German National Cohort (NAKO)

BACKGROUND: The nasal microbiome plays an important role in respiratory and systemic health, but data from large adult population cohorts remain scarce. We analyzed nasal microbiota from 2,070 adults aged 21–73 years in the population-based German National Cohort (NAKO) to characterize community composition and identify host factors associated with variation in the anterior nares’ microbiome. Microbial profiles were obtained using 16S rRNA gene sequencing, and associations with host characteristics—including sex, age, body composition, tobacco smoking, pulmonary function, household context, and self-reported physician diagnoses—were evaluated using a two-stage regression framework, beta diversity analyses, and complementary Latent Dirichlet Allocation (LDA) community modeling. RESULTS: Despite detecting 358 genera across the cohort, more than 90% of all sequencing reads were assigned to only 15 genera. These core genera showed distinct associations with host physiology and lifestyle. Sex and body mass index were the strongest correlates of alpha and beta diversity, while pulmonary function and tobacco smoking were associated with differences in the relative abundance of several commensal taxa, including Lawsonella, Cutibacterium, and Dolosigranulum. Age was not related to overall diversity but exhibited characteristic shifts in community composition. Antibiotic use within the previous 12 months was associated with lower levels of multiple commensal genera and higher relative abundance of Staphylococcus. LDA-derived sub-communities largely mirrored the genus-level associations and indicated that these patterns reflect transitions between recurrent nasal community types rather than isolated changes in single taxa. CONCLUSIONS: This nationwide study provides a detailed characterization of nasal microbiome patterns in the general adult population (up to 73 years) of Germany and highlights that multiple host factors are associated with both taxon-specific and community-level variation. The findings offer a reference for future investigations into the role of the nasal microbiome in respiratory and systemic health.