Underactive bladder as defined by the International Continence Society in the 2023 Japan Community Health Survey

To investigate the characteristics of underactive bladder (UAB) in participants of the 2023 Japan Community Health Survey (JaCS 2023).

The JaCS 2023 was conducted among individuals aged 20-99 years old who had anonymously registered with a Japanese online research company. We divided the 6210 participants of JACS 2023 into UAB and non-UAB groups as defined by the International Continence Society Working Group (ICS-WG) and evaluated the prevalence of UAB as well as concomitant lower urinary tract symptoms. In addition, an association between UAB and vulnerability-related factors, namely participants' characteristics including frailty and comorbidities, was explored by univariable and multivariable analyses.

The prevalence of UAB in Japanese community-dwelling men and women aged 20 years or older was 9.3% and 4.0% overall (p < 0.0001), respectively, and when excluding benign prostatic hyperplasia or pelvic organ prolapse, 7.0% and 3.7%, respectively, (p < 0.0001). A significant increase in the prevalence of UAB with age was observed (p < 0.0001). In addition, storage symptoms including overactive bladder were more frequent in the UAB group than the non-UAB group (p < 0.0001). Frailty and several comorbidities were independently associated with UAB.

According to the definition proposed by the ICS-WG, the JaCS 2023 demonstrated that UAB was more prevalent in men than in women and increased in prevalence with age. Storage symptoms including overactive bladder sometimes coexisted with UAB. Vulnerability-related factors were associated with UAB.