Childhood Nocturnal Enuresis as a Risk Factor for Overactive Bladder in Young Adults

Nocturnal enuresis (NE), or bedwetting after age 5, is a common childhood condition, affecting approximately 15% of children and declining to 1% by age 15 due to spontaneous resolution. Consequently, it has traditionally been considered a benign condition. However, this perspective has been challenged by reports linking a history of childhood NE to lower urinary tract symptoms (LUTS) in middle-aged and older adults. Conversely, it remains unclear whether this risk extends to overactive bladder (OAB) in younger populations [1-3]. This study determined whether a history of childhood NE is a risk factor for OAB in young adults. The Institutional Review Board of Kansai Medical University approved this cross-sectional study (no. 2022124). Data were collected through an online Google Forms questionnaire from November 27, 2024, to December 6, 2024, with informed consent obtained from all participants. The questionnaire was distributed to 1189 students enrolled in the medical and nursing faculties at Kansai Medical University and was used to collect data on age, sex, height and weight, history of NE (including presence, age at resolution, history of consultation, and treatment), and OAB Symptom Score (OABSS). The history of NE was assessed through the question: “Did you wet the bed at least once a month after starting elementary school?” OAB was defined as an OABSS urgency score of ≥ 2 and a total score of ≥ 3, based on standard diagnostic criteria. Fisher's exact test was used to compare categorical variables. Overall, 622 students (247 males and 375 females) responded (response rate, 52.3%). The median age of respondents was 23 years (interquartile range, 21–25). A history of NE was reported by 66 (10.6%) respondents, comprising 33 males (13.4%) and 33 females (8.8%). Further characteristics of the respondents are presented in Table 1. OAB prevalence was significantly higher in young adults with a history of NE than in those without: 13.6 versus 3.2% in total (p = 0.001, odds ratio [OR] = 4.7), 12.1 versus 1.9% in males (p = 0.013, OR = 7.2) and 15.2 versus 4.1% (p = 0.018, OR = 4.2) in females. Item-by-item analysis of the OABSS showed that scores for nocturia, urgency, and urgency incontinence were significantly higher in participants with a history of NE, whereas no significant difference was observed in daytime frequency (Table 1). Our study demonstrates that young adults with a history of NE have a significantly higher prevalence of OAB. The 13.6% OAB prevalence in our NE cohort is markedly higher than the 6%–7% reported for the general Japanese population aged 20–29 years [4]. Our findings extend those of previous research that linked childhood NE to LUTS in middle-aged adults [1-3], providing novel evidence that this risk is already present in individuals in their 20s. The persistence of these symptoms suggests that underlying pathophysiological factors, including detrusor overactivity, do not fully resolve when enuresis ceases. This implies that childhood NE may be a clinical marker for a persistent predisposition to bladder dysfunction [5]; rather than a simple maturational delay, which manifests as OAB later in life. Our findings have significant clinical implications, challenging the traditional view of NE as a benign condition. A history of NE warrants long-term monitoring. Paediatricians should counsel families about this potential long-term risk; proactive questioning about OAB symptoms during routine check-ups could facilitate earlier diagnosis and improve quality of life. This study had some limitations. First, potential selection bias cannot be excluded. The response rate was 52.3%, and individuals with urinary symptoms might have been more inclined to participate. Furthermore, our cohort of medical students may exhibit a different prevalence of neurodevelopmental disorders, which are associated with NE and OAB. However, the prevalence of NE (10.6%) and OAB (4.3%) in our cohort was comparable to that of the general population, suggesting that this bias was not substantial. Second, our data relied on participant recall of childhood events and did not include details on the type or severity of NE. Third, as a single-centre study in Japan, the generalisability of our findings to other populations may be limited. Future prospective cohort studies are needed to address these issues. In conclusion, a history of childhood NE is a significant risk factor for OAB in young adults. Conceptualization, S.A. and K.K.; data curation, A.I. and S.A.; funding acquisition, Y.A.; formal analysis, A.I., S.A., and S.T.; investigation, A.I. and S.A.; methodology, S.A.; project administration, S.A.; supervision, K.K.; visualisation, A.I. and S.A.; validation, S.K., S.T., and Y.A.; writing – original draft, A.I. and S.A.; writing – review and editing, S.K., S.T., Y.A., and K.K. All authors have read and agreed to the published version of the manuscript. An earlier version of this research was presented by Ms. Ayaka Ito at the 36th Annual Meeting of the Japanese Society on Enuresis and Incontinence in June 2025; where it received the Best Encouragement Award. We thank Editage (www.editage.com) for the English language editing. The authors declare no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.