This is the first nationally representative estimate of the prevalence of enuresis in the United States based on standardized diagnostic criteria. We found that 4.45% of U.S. children ages 8 to 11 years have enuresis. In addition to replication of the demographic correlates of enuresis from previous studies conducted outside the United States, we also show an association between enuresis and ADHD that has been shown in previous studies.
Our finding of the maximal prevalence of enuresis at age 8 years, followed by a decline to age 11 years, is consistent with the findings of most previous studies.1–8,10–12,18,19
Also confirming the findings of previous population-based surveys,1,5–7,10,19
there was a 2.7-fold greater risk of enuresis among boys than girls. We also found that black parents reported a twofold higher rate of enuresis in their children than white parents, which persisted after controlling for socioeconomic status. This association confirms previous studies of demographic correlates of enuresis.14,17,27
Contrary to previous clinical studies,31,32
socioeconomic status was not associated with enuresis in the current study.
The association between enuresis and ADHD confirms the findings of previous clinical studies31,33–42
and population-based studies6,7,10,18
in a large nationally representative sample. Although we could not address the explanations for this association, previous research has suggested that both enuresis and ADHD are related to delays in central nervous system maturation. This hypothesis is supported by findings of growth delay43
and a higher rate of rhythmic slow wave activity on EEG.44
However, the results of a family study suggest that ADHD and enuresis are etiologically independent.45
Comorbidity between enuresis and ADHD could either be due to common etiologic pathways underlying these two conditions or due to “causal” relations in which the nonresolution or treatment of one disorder increases the risk for the other disorder.46
Prospective studies, such as the Great Smoky Mountains Study of Youth,15
found that enuresis has a high level of continuity at 3- to 7-year follow-up. However, these authors did not report on whether the presence of enuresis earlier in life increased the risk of ADHD or other psychiatric disorders later in life. In a retrospective study, a higher rate of childhood enuresis was found among adults with bipolar disorder as compared with adults without mood disorders.47
Future developmental epidemiological studies are needed to better understand the comorbidity between enuresis and other psychiatric disorders and the possible role of enuresis in the development or nonresolution of other disorders.
Treatment targets for enuresis include arousal, nocturnal urine production, and abnormalities in urine storage/voiding.48
Management of enuresis includes maintaining a voiding diary, addressing the often comorbid constipation, alarms, and medications (imipramine and desmopressin).48
The use of alarms for children with enuresis is associated with nearly 4 fewer wet nights per week compared with no treatment or placebo.49
The NHANES collected information about the use of medications for bed-wetting but did not collect information about the use of alarms. Our finding that a little more than one third of the children with enuresis received health service confirms the findings of previous epidemiological studies.1,13
The relatively small proportion of children who received health service could be an indication that many families wait for spontaneous resolution of the symptoms. This may be especially true of familial enuresis, for which the parents have reason to expect resolution of symptoms. Lack of medical attention to enuresis may also be a cause for concern because the persistence of enuresis past the age of 7 years is frequently associated with low self-esteem in children.28,29
In addition to reducing enuresis symptoms, successful treatment of enuresis is also associated with improvement in self-esteem.28,50
In the current study, lower odds of receiving health service for enuresis was associated with comorbid ADHD.
Recent studies, including a double-blind randomized placebo-controlled trial, have noted that atomoxetine, a medication that is approved for the treatment of ADHD, has been found to decrease frequency of bedwetting among children with enuresis with or without ADHD.51,52
Interestingly, an earlier study found that the presence of ADHD predicted worse outcome for treatment of enuresis with alarm, DDAVP, or imipramine.53
In the current study, children with ADHD who received medications were less likely to report enuresis than children ADHD with who did not receive medications. Among the 117 children with ADHD, 10 (14.3%, SE 4.4) of the 87 who did not receive medications for ADHD reported enuresis. Only 2 (7.4%, SE 7.1) of 30 children who received ADHD medications reported enuresis. However, this difference was not statistically significant (χ2
= 0.597; p
= .446). More studies are needed to clarify the relation between treatment of ADHD/enuresis and the resolution of the other disorder.
There are several limitations of this study. First, the diagnosis of enuresis was not validated by medical evaluation. The diagnosis of DSM-IV enuresis requires exclusion of medical conditions that may have contributed to bed-wetting. As with most epidemiological studies, medical evaluation was not part of the diagnostic assessment in the current study. However, C-DISC 4.0, which was used in 2001–2004 NHANES (data used in the current study), does include a question: “In the last year, has [he/she] suffered from any medical condition that made [him/her] wet the bed during the night?” The presence of constipation, which is frequently a cause of enuresis, was not assessed specifically. A second limitation is the lack of an independent assessment of impairment at school or another situation because of inattention/hyperactivity symptoms. The DSM-IV diagnosis of ADHD requires information about impairment in two settings (e.g., at home and at school). Although the DSM-IV does not specifically require it, two-situation impairment is best established by interviewing caregivers in two different situations, for example, at home and at school. In this study, we have only the parent’s report of impairment at school and at home. The third limitation is that this study could not provide information on causal links between these conditions because of the cross-sectional nature of the study. Moreover, there was no direct clinical evaluation of the history of onset of these conditions, and there was no systematic evaluation of potential factors that could explain these conditions.
Overall, this study highlights the common occurrence of enuresis in children ages 8 to 11 years and its frequent comorbidity with ADHD. These findings suggest that children being assessed for either ADHD or enuresis should also be evaluated for the presence of the other condition. This study shows that few families seek treatment for enuresis, although earlier studies suggest that this disorder causes significant distress and family burden, especially in children older than 7 years. The findings of this study suggest that it is important to specifically inquire about symptoms of bed-wetting and its effects on the emotional health of the child and the family. Future longitudinal research is needed to determine the following: the influence of ADHD and other comorbid disorders on the persistence or re-emergence of enuresis, the factors that influence families to seek health service/treatment for enuresis, and the impact of treating one condition (enuresis or ADHD) on the concurrent symptoms or future occurrence of the other condition.