Serotonin (5-hydroxytryptamine [5-HT]) is one of several important neurotransmitters associated with micturition. At the 36th annual European Association of Urology virtual congress, investigators presented new research correlating lower serum 5-HT levels with overactive bladder (OAB) symptoms.

Of 1024 individuals in the Iwaki Health Promotion Project, 118 (44 male and 74 female) had OAB and 906 did not. OAB was defined as at least 1 episode of urge urinary incontinence weekly and a total OAB Symptom Score (OABSS) of 3 or higher.

The OAB group had significantly lower serum 5-HT levels than the group without OAB: 111 vs 134 ng/mL, Teppei Okamoto, MD, of Hirosaki University Graduate School of Medicine in Japan, reported on behalf of his team. Lower serum 5-HT also significantly correlated with higher total OABSS. In a multivariate logistic analysis, lower serum 5-HT levels emerged as a possible independent risk factor for OAB along with older age.

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Many 5-HT receptors are associated with bladder contraction, Dr Okamoto explained in an oral presentation. The 5-HT 1D receptor in particular is widely distributed in the urothelium. It is believed that when urinary 5-HT 1D joins to its receptor it inhibits ATP release for dilatation. Thus, low serum 5-HT 1D levels might be a marker of low urinary 5-HT 1D levels and bladder hypersensitivity, he concluded. Whether low serum 5-HT levels causes OAB requires further research.

Other results showed that the groups with and without OAB differed significantly in their history of cardiovascular disease, chronic kidney disease, hypertension, diabetes mellitus, and Center for Epidemiologic Studies Depression score.


Okamoto T, Imai A, Hatakeyama S, et al. Serum serotonin level as an independent factor for overactive bladder: Results from the community based cross-sectional study in Japan. Presented at the EAU 2021 virtual conference, July 8-12, 2021. Abstract P0014.