Objective: Although epidemiological surveys generally indicate declining rates of bedwetting with age, recent studies show that children with severe nocturnal enuresis have lower prevalence rates, which persist into adolescence. This study reports prevalence rates of both infrequent bedwetting (IB) and nocturnal enuresis (NE) at five time points during childhood with a large cohort of children.
Material and methods: The Avon Longitudinal Study of Parents and Children provided a cohort of 13,973 singleton/twin infants alive at 12 months. These were followed up at 54, 65, 78, 91 and 115 months with a questionnaire relating to frequency of bedwetting and other variables. The prevalences of IB and NE were derived from these measures with missing data imputation being used to correct for possible loss-to-follow-up bias.
Results: The overall prevalence rate of bedwetting declined from 30% (54 months) to 9.5% (115 months), being most pronounced between 54 and 65 months. Children with NE (wet at least twice a week) had lower prevalence rates at all ages but were more likely to persist with the problem over time and to have the non-monosymptomatic type of bedwetting compared to children with IB.
Conclusions: Children with the severest form of bedwetting are likely to persist with the problem and to have the more complex form (non-monosymptomatic). The results are discussed in relation to the clinical importance of early identification.