(1206) Age-Related Changes in the Nasal Microbiota: A Systematic Review

Introduction: The nasal microbiota plays a key role in upper airway immunity and respiratory health, yet how it changes across the human lifespan and its relationship to disease remains incompletely understood. This review examines age-related nasal microbiota composition and its associations with respiratory and systemic conditions.

Methods: A systematic PubMed review was conducted for studies published between 2015 and 2025. Four reviewers screened studies using predefined inclusion and exclusion criteria. Eligible studies assessed nasal microbiota across age groups or disease states. Study quality was evaluated using the Downs and Black risk-of-bias tool. Data collected included number of patients, age, gender, clinical presentation, and potential disease pathogenesis.

Results: Twenty studies spanning infancy to advanced age were included. Actinobacteria, Firmicutes, and Proteobacteria dominated across all ages. Infants exhibited higher abundance of Moraxella, Haemophilus, and Streptococcus, linked to wheezing, asthma, and respiratory infections. Adolescents and adults showed greater microbial stability with Corynebacterium and Staphylococcus predominance. Older adults had reduced diversity and increased potentially pathogenic taxa, notably seen in chronic rhinosinusitis, neurodegenerative disease, as well as institutionalized populations.

Conclusions: Age-related shifts in the nasal microbiota reflect interactions between immune development, environmental exposure, and host physiology. Infancy and older age show increased disease susceptibility, whereas adolescence and adulthood demonstrate relative microbial stability. These findings highlight potential targets for age-specific prevention and therapeutic strategies.