Gender differences in the healthy lower airway microbiome

<bold>Introduction:</bold> Gender disparities in lung disease have been observed regarding prevalence, symptoms, and outcomes. The interplay between the lung microbiome and respiratory health is slowly being unveiled, but gender-specific variations in microbial composition remain underexplored. We aimed to examine the lung bacterial microbiome in healthy lungs according to gender. <bold>Methods:</bold> BAL was sampled from the right middle lobe with bronchoscopy in 100 healthy volunteers, age 35-81. Whole genome sequencing was performed with Illumina NovaSeq. Identification of taxa was made by the GAIA 2.0-software. Statistical analyses were performed in R (Phyloseq-, DESeq2- and AncomBC-packages). <bold>Results:</bold> Alpha diversity was significantly lower in women (p=0.01), based on observed data, but not on other measurements. Bray-Curtis dissimilarity was not significantly different between groups. With DESeq2, 16 species were differentially abundant, of which 15 were more prevalent in males, top 2 being Alloscardovia omnicolens and Citrobacter koseri, whereas Coriobacteriaceae bacterium was more prevalent in women (Figure 1). With AncomBC, 9 species were differentially abundant, 7 in women, top 2 were Blautia hansenii and Coriobacteriaceae bacterium, while Streptococcus mitis and Parvimonas micra were more prevalent in men. <bold>Conclusion:</bold> The lung microbiome for men and women is mostly similar, but several several species are differentially abundant. Further research is needed. <fig><object-id>erj;64/suppl_68/PA454/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>