Incidence of enuresis and encopresis among children with attention-deficit/hyperactivity disorder in a population-based birth cohort

Objective: This study reports the incidence of enuresis and encopresis among children with attention-deficit/hyperactivity disorder (ADHD) versus those without ADHD. Methods: Subjects included 358 children (74.5% boys) with research-identified ADHD from a 1976 to 1982 population-based birth cohort (n = 5718) and 729 (75.2% boys) non-ADHD control subjects from the same birth cohort, matched by gender and age. All subjects were retrospectively followed from birth until a diagnosis of enuresis or encopresis was made or last follow-up before 18 years of age. The complete medical record for each subject was reviewed to obtain information on age of initial diagnosis of an elimination disorder, frequency and duration of symptoms, and identification of exclusionary criteria specified by DSM-IV, with confirmation of the diagnosis by expert consensus. Results: Children with ADHD were 2.1 (95% confidence interval [CI], 1.3-3.4; P =.002) times more likely to meet DSM-IV criteria for enuresis than non-ADHD controls; they were 1.8 (95% CI, 1.2-2.7; P =.006) times more likely to do so than non-ADHD controls when less stringent criteria for a diagnosis of enuresis were employed. Though not significant, children with ADHD were 1.8 (95% CI, 0.7-4.6; P =.23) times more likely to meet criteria for encopresis than non-ADHD controls. The relative risk was 2.0 (95% CI, 1.0-4.1; P =.05) when a less stringent definition for encopresis was utilized. Conclusions: Children with ADHD are more likely than their peers without ADHD to develop enuresis with a similar trend for encopresis.