Purpose: To explore associations between the gut microbiome and overactive bladder (OAB) with daily urinary urgency among individuals reporting this diagnosis within a single community.
Methods: This cross-sectional study surveyed 1113 individuals who participated in the Iwaki Health Promotion Project in Japan. OAB was defined as urinary urgency at least once per week and an Overactive Bladder Symptom Score (OABSS) of ≥ 3. OAB with urinary urgency at least once a day was defined as daily urgency. The gut microbiomes were assessed by next-generation sequencing of 16S rRNA genes extracted from fecal samples. The participants were divided into two groups: OAB-daily urgency and non-OAB. Cases were selected for inclusion on the basis of 1:1 propensity score matching; we assigned 58 individuals to each group (23 men and 35 women) for our analysis.
Results: Individuals reporting OAB with daily urinary urgency demonstrated a lower bacterial diversity between individuals (Bray-Curtis distance 0.48 vs. 0.53, P < 0.001); the results cluster differently in the non-OAB groups. The relative abundance of genus Bifidobacterium was significantly lower among those reporting daily urgency (2.41% vs. 4.23%, P = 0.014). By contrast, the relative abundance of genus Faecalibacterium (9.25% vs. 6.26%, P = 0.006) was significantly higher in this group.
Conclusion: We observed significant differences in gut microbial contents and specific bacterial genera in association with OAB with daily urgency. Further study will be necessary to assess causal relationships between the gut microbiome and OAB.
Keywords: Bifidobacterium; Faecalibacterium; Gut microbiome; Overactive bladder; Urinary urgency.