The association between serum serotonin levels and overactive bladder: results from a community-based cross-sectional study in Japan.

PURPOSE: To investigate the association between serum serotonin (5-HT) levels and overactive bladder (OAB) in a community-dwelling population. METHODS: This cross-sectional study analyzed 1024 subjects who participated in the Iwaki Health Promotion Project in 2015 in Hirosaki, Japan. OAB was assessed using the Overactive Bladder Symptom Score (OABSS). OAB was defined as an occurrence of urinary urgency at least once a week and an OABSS of ≥ 3. We assessed serum 5-HT levels, laboratory data, and comorbidities of each participants. Participants' mental health status was evaluated using the Center for Epidemiologic Studies Depression (CES-D) scale. The association of serum 5-HT levels and OAB was analyzed by multivariable logistic regression analysis. RESULTS: This study included 394 men and 630 women. Of those, 118 (44 male and 74 female) were OAB sufferers. There were significant group differences in age, history of cardiovascular disease, chronic kidney disease, hypertension, diabetes mellitus, and CES-D score. Participants' serum 5-HT levels in the OAB group were significantly lower than those in the non-OAB group (100 vs. 127 ng/mL, P < 0.001). Multivariable analysis showed that age (odds ratio [OR]; 1.06, 95% confidence interval [CI]; 1.04-1.08, P < 0.001) and log serum 5-HT level (OR; 0.25, 95% CI; 0.10-0.68, P = 0.006) were independently associated with OAB. CONCLUSIONS: Lower serum 5-HT levels could independently be associated with the presence of OAB. Further study is necessary to elucidate a possible causal relationship between serum 5-HT levels and OAB.