Exploring gut microbiota diurnal fluctuation in alcohol-dependent patients with sleep disturbance

Introduction. Alcohol dependence (AD) and sleep disturbance (SD) independently affect gut microbiota, potentially disrupting the circadian rhythm of the microbiota and the host. However, the impact of SD on the composition and rhythmicity of gut flora in AD patients remains poorly understood.Gap Statement. Characteristics of gut flora and diurnal oscillations in AD patients experiencing SD are unknown.Aim. This study aims to explore alterations in gut flora and diurnal oscillations in AD patients experiencing SD.Methodology. Thirty-two AD patients and 20 healthy subjects participated, providing faecal samples at 7 : 00 AM, 11 : 00 AM, 3 : 00 PM and 7 : 00 PM for gut microbiota analysis using 16S rDNA sequencing. AD patients were further categorized into those with poor sleep (ADwPS) and those with good sleep (ADwGS) for further analyses.Results. The ADwPS group demonstrated elevated levels of anxiety, depression and withdrawal severity compared to the ADwGS group (all P<0.05). The β-diversity of gut microbiota in the ADwPS group differed from that in the ADwGS group (P<0.05). Bacterial abundances at various taxonomic levels, including Cyanobacteria and Pseudomonadales, differed between the ADwPS and ADwGS groups (all P<0.05). Utilizing unweighted UniFrac analysis, the β-diversity of gut microbiota in the ADwPS group demonstrated robust diurnal oscillation (P<0.05), whereas this pattern was statistically insignificant in the ADwGS group. Notably, the abundance of pathogenic bacteria like Pseudomonadales and Pseudomonadaceae exhibited marked diurnal fluctuation in the ADwPS group (all P<0.05).Conclusion. SD in AD patients extends beyond alcohol-induced alterations, impacting gut microbiota composition, function and diurnal oscillation patterns. This highlights its add-on influence, supplementing AD-related changes.