Indoor Airborne Bacteria and Lung Health: Sex-Specific Associations

Abstract

Background Sex is a significant epidemiological factor in the incidence of respiratory disease. However, the role of sex in indoor bacterial exposure remains largely unexplored. Objective Our objective was to investigate the association between indoor bacterial exposure and lung function and airway inflammation, focusing on sex-specific differences. Methods Airborne dust samples from the bedrooms of 463 men and 575 women in the European Community Respiratory Health Survey (ECRHS) III from five Nordic cities were subjected to 16S rRNA amplicon sequencing to characterize bacterial communities. Limulus amebocyte lysate (LAL) assay and qPCR were used to measure endotoxin and bacterial load, respectively. Sex stratified adjusted linear regression analysis were used to examine the association between bacterial profile and lung function and FeNO measurements. Results Higher indoor bacterial diversity were significantly associated with higher lung function (FVC and FEV1 Z-scores) in men only, and with higher FeNO levels in women only. Indoor endotoxin levels were significantly associated with higher FeNO levels in women only. No clear associations were found between endotoxin levels and lung function. Most bacterial genera associated with higher lung function were affiliated with the Actinobacteriota phylum. Higher relative abundance of Bacteroidia, and Patescibacteria were associated with lower lung function, and the same was seen for several bacterial genera considered to be part of the core oral microbiome, including Streptococcus and Veillonella. More bacterial genera were associated with high FeNO levels in women than in men, among them Campylobacter, Fusebactrium, and several Bacteroidia genera. Conclusions The results of our study indicate that there might be distinct sex-specific differences in how individuals respond to indoor bacterial community exposure and its impact on lung health. This underlines the importance of talking sex into consideration in future evaluations of health implications associated with various indoor microbial communities.