Trajectories of daytime wetting and soiling in a United Kingdom 4 to 9-year-old population birth cohort study

Purpose: This longitudinal, population based study describes trajectories of daytime wetting and soiling in children 4.5 to 9.5 years old. Materials and Methods: Participants consisted of a cohort of nearly 11,000 children forming part of the United Kingdom population based cohort study known as ALSPAC (Avon Longitudinal Study of Parents and Children). Repeated measures of parentally reported incidents of daytime wetting and soiling were modeled using longitudinal latent class analysis. Results: Developmental variation could be adequately described by 4 trajectories for each of daytime wetting and daytime soiling. Trajectory shapes could be interpreted as normative (daytime wetting 86.2%, daytime soiling 89.0%), delayed (6.9%, 4.1%), persistent (3.7%, 2.7%) and relapsing (3.2%, 4.1%). There were gender differences among many of the nonnormative groups defined by these trajectories. In particular, girls outnumbered boys by a ratio of 1.25:1 among those with persistent wetting and a ratio of 1.39:1 among those who suffered a relapse in daytime wetting. In contrast, boys outnumbered girls by a ratio of 1.63:1 among those who were delayed in bowel continence, 1.93:1 among those with persistent soiling and 1.80:1 among those who suffered a relapse in soiling. Conclusions: Identification of trajectories of daytime wetting and soiling in children is an essential starting point in understanding the development of bladder and bowel control. These findings can be used to examine risk factors for the different trajectory groupings identified in the study.