Association between gut actinobacteria and obstructive sleep apnoea severity in Japanese adults

Gut microbiota are known to mediate human health and are affected by physiological conditions, including hypoxia. Although studies involving animal models have shown that intermittent hypoxia alters gut microbiota, its effects in adult Japanese patients with obstructive sleep apnoea (OSA) remain unclear. We investigated the association between OSA severity and gut microbiota composition in Japanese adults with OSA.

This cross-sectional study included 74 Japanese diagnosed with OSA via polysomnography. The average body mass index was 30.5 ± 3.8 kg/m² and the average 3 % oxygen desaturation index (ODI) was 39.9 ± 20.0. No control group was included. Faecal samples were collected in a fasting period of >10 h. The association between 3 % ODI and gut microbiota were analysed at the phylum, family and genus level.

At the phylum level, 3 % ODI significantly positively correlated with Actinobacteria (r = 0.3151, p = 0.0126) and negatively correlated with Firmicutes (r = -0.3150, p = 0.0126). No significant correlations were found with Proteobacteria or Bacteroidetes. At the family level, 3 % ODI significantly positively correlated with Bifidobacteriaceae in Actinobacteria (r = 0.2373, p = 0.0418). At genus level, Bifdobacterium was prominently increased compared with other group.

This study showed that the gut microbiome in Japanese with OSA showed an increase in Bifdobacterium. Although our cohort was biased towards moderate obesity and severe OSA severity, intermittent hypoxia might contribute to the change of gut microbiome. These findings suggest that increased Bifdobacterium may help maintain gut homeostasis under hypoxic stress, especially in Japanese.