Objective: To determine the prevalence of nocturnal enuresis (NE) in a large cohort of children at 7.5 years old, and to examine the frequency of variables such as gender, severity, associated elimination problems, and clinical signs within the identified group.
Subjects and methods: Of an original cohort of 13 971 infants alive at 12 months, 11 251 who were still active in the Avon Longitudinal Study of Parents and Children (ALSPAC) survey, were followed at 91 months. The mother or main carer was given a questionnaire which asked, amongst other items, about the presence and frequency of bedwetting, other elimination problems, and signs related to the wetting behaviour; 8269 (73.5%) questionnaires were returned and 8151 contained information on the frequency of bedwetting.
Results: In all, 1260 children (15.5%) at 7.5 years wet the bed, but most wet once or less a week, and only 215 (2.6%) met the Diagnostic and Statistical Manual of Mental Disorders (fourth edition) criteria of NE (wetting at least twice a week). A higher prevalence was reported in boys than girls and 266 children (3.3%) had both daytime wetting and bedwetting, with 189 (2.3%) having both daytime soiling and bedwetting. Daytime urgency increased with severity of bedwetting and occurred in 28.9% of children with NE.
Conclusion: At 7.5 years old the incidence of bedwetting is high, but only 2.6% of this large population-based sample wet at a frequency meeting the definition of NE. Although a small percentage of children had both daytime wetting and bedwetting, the evidence suggests that these are discrete problems. Amongst children with NE, indicators of bladder overactivity were present, supporting the view of heterogeneity and the importance of individual assessment in deciding on appropriate treatment.