Margaret W. Fockema, Division of Urology, Department of Surgery, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2194, South Africa. e-mail: firstname.lastname@example.org
Study Type – Symptom Prevalence (prospective cohort)
Level of Evidence 2a
What's known on the subject? and What does the study add?
Nocturnal enuresis is a common childhood problem. Although its prevalence is known in many countries, no data are available from South Africa and it is difficult to extrapolate data from developed countries to a population with such diverse conditions and resource-poor settings.
This study is the first to report on the 16% prevalence rate and the low level of parental knowledge of enuresis in South African children aged between 5 and 10 years.
•To establish the prevalence of NE in 5–10 year old South African children in a cross-sectional study using a parent-completed questionnaire.
•To establish the parental perception and associated factors of mono-symptomatic nocturnal enuresis (MNE) treatment and treatment success rates in 5–10 year old children from South Africa.
PATIENTS AND METHODS
•A total of 4700 questionnaires were distributed to children at 37 selected schools willing to participate from South Africa. Parents anonymously filled out the questionnaire.
•Data were reported as frequencies and percentages of NE in tables according to different gender and age groups.
•The Chi-square test compared proportions between groups and Fisher's Exact test corrected for small numbers of observations (n ≤ 5). Age differences were determined using Student's t-test. A P-value ≤0.5 was considered to be statistically significant.
•The questionnaire's response rate was 72.1%, with 3389 children included in the study.
•The overall prevalence of NE was 16.0%–14.4% of children suffered from mono-symptomatic NE (MNE). The prevalence of NE in boys was double that in that in girls.
•Only 28.3% had received some form of treatment, whereas 13.5% had been medically treated by a doctor. Parents’ awareness of treatment modalities available is outdated and most of the management of MNE was done by parents themselves, albeit with low success rates.
•A positive family history was found in 50.5% of children suffering from MNE.
•Constipation was a problem in 15.8% of children with enuresis.
•This is the first study to estimate the prevalence of NE and report on the parental perception and possible associated factors of enuresis in children from South Africa. The study showed that South African children have a similar prevalence rate of NE (16%) when compared with other countries.
•The possible associated factors with MNE in South Africa include constipation and a family history of enuresis.
•Finally, there are low levels of parental knowledge of treatment modalities of MNE, leaving many children untreated.
Nocturnal enuresis (NE) is defined as the intermittent incontinence of urine while sleeping, regardless of the presence or absence of concomitant daytime symptoms according to the International Children's Continence Society. Bed-wetting during sleep is often seen as a psychological problem by clinicians, as well as the general public. NE is a very common childhood problem , which is rarely discussed at home. Definitions used for NE vary considerably and the terminology used can often be confusing or present a problem when comparing data [1–3]. Table 1 lists the International Children's Continence Society definitions of enuresis used in this study.
Intermittent incontinence of urine while sleeping, regardless of the presence or absence of concomitant daytime symptoms
Monosymptomatic NE (MNE)
NE in a child without any other lower urinary tract symptoms
Primary NE (PNE)
NE in a child who has previously been dry for less than 6 months
Secondary NE (SNE)
NE in a child who has previously been dry for at least 6 months
Age and gender are core descriptors of NE. Generally, children between the ages of 5 and 16 years have been investigated [1,4]. Large epidemiological studies show a decrease in the prevalence of NE with age [3,5]. A review of studies from western countries showed an NE frequency of 8.0% for 7 year olds, decreasing to 3.0% and 0.8% for 11–12 years olds and 16 year olds, respectively . There seems to be consensus that the frequency of NE in boys is greater than in girls, with the female to male ratio varying from 1:4.1 to 1:2.1 [1,5–7].
The prevalence of NE episodes varies in children. A study in the USA showed that 15.0% of children with NE have enuretic episodes every night, although most children had an episode more than once per week . Studies in the UK and Malaysia showed that 8.2% and 20% of children, respectively, have enuretic episodes every night [2,6]. However, these studies have not reported on frequencies for separate age groups. Yeung et al. show a decrease in overall prevalence of primary NE with increasing age, but the proportion of patients with severe enuretic symptoms increases with age.
Parents and treating physicians often treat NE as a psychological problem; however, the parental perception of NE can often, in turn, cause psychological damage to children suffering from NE through punishment, shaming and lack of support. Parental concern is often not high and, as a result, most children suffering from NE are not treated at all. A study in Nigeria reported that parents believed NE was caused by urinary tract infections, deep sleep and excessive play . A Turkish study showed that over 75% of enuretic children were not taken for treatment . Furthermore, in Malaysia only 5.8% of parents had taken their child to see a medical doctor, 5.2% had seen a traditional healer and 87.0% had not sought any medical consultation . The latter is partly because the condition often resolves spontaneously, or parents are unaware of treatment modalities. Figure 1 serves to illustrate the low percentage of parents with children suffering from NE in various countries that seek advice from healthcare workers, with the exception of Australia and Italy [6,7,9–13]. On the other hand, there is a strong tendency for families to self-treat their children who suffer from NE with behavioural strategies . As seen in Table 2, many findings of self-treatment have been reported from other countries [7,10,12,13]. These studies showed that behavioural modifications, such as fluid restriction, waking the child at night to void and counselling, are the most commonly used modalities for the treatment of NE. Although these treatment options have low success rates in many children, with limited evidence in the literature supporting their use, they are still the treatment of choice for most parents .
Table 2. Percentage use of behavioural strategies by parents for managing nocturnal enuresis in different countries [7,10,12,13]
Voiding before bedtime
Waking to void
Waiting for maturity
The possible cause of NE is misunderstood by parents the world over. Even though previous studies from other countries have linked many potential causative factors to NE, whether these factors are truly causative or merely associated with NE has, for the greater part, not been established.
As shown by many studies, NE runs in families . In a study comparing parental, sibling and other consanguineous relatives' history of NE in enuretic and non-enuretic children aged 5–15 years, results showed that 16.0% of children with NE had siblings with NE . Furthermore, approximately 14.0% of children with NE had a parent with a history of NE, whereas a lower prevalence of NE was reported in children whose family members did not suffer from NE .
Constipation is also a common problem in children suffering from NE and a study from Turkey found that 21.6% of children suffering from NE also suffered from constipation . The pressure effect of the stool on the bladder could cause an uninhibited contraction of the detrusor muscle . It is therefore important to detect and treat constipation in enuretic children as a potential cause [3,7].
Associations between NE, poor school performance and learning problems have been reported . Although parents and many medical professionals believe that NE is caused by stressful events in a child's life, accumulating evidence shows that psychological problems are more likely caused by the NE, rather than being a cause thereof [10,16–18]. Either way, causality has not been established. The parental response to NE often leads to shame, guilt and avoidance of peer contact . In addition, NE may result in low self-esteem, psychological problems and poor school performance [10,17,18]. Hence, it follows from the literature that children with NE do not necessarily have psychological problems requiring psychotherapy .
Study data from developed countries are difficult to extrapolate to a South African population because of the diverse conditions and resource-poor settings present in South Africa. At present, no data are available on the prevalence or severity of NE, the parental perception of monosymptomatic NE (MNE) or the factors associated with NE in South African children. This study is therefore the first to investigate and report on such data from South African children suffering from NE.
PATIENTS AND METHODS
A cross-sectional study using a questionnaire was set up to determine the prevalence and severity of NE, as well as daytime symptoms, in the different gender and age groups of children in South Africa; to record which treatment options, if any, were being sought by parents with enuretic children in South Africa and the perceived success of these different treatment modalities; and to determine factors associated with NE in South African children. Specific factors investigated included the child's family history of NE, constipation and psychological stress factors. The study was based on a population sample of selected schools in a middle-class setting.
A small pilot study conducted in a total of 200 children, aged 4–10 years, showed a prevalence of NE of 34.0%. This was considerably higher than the average prevalence reported from other countries  and highlighted the importance of a prevalence study for NE in the South African community (unpublished data).
Based on the pilot data, it was conservatively assumed that the prevalence of NE from a finite population of 1 million people is 15.0%. As the study is dependent on respondent-driven sampling, a convenience sampling approach was used to calculate sample size. Using a study power of 0.95, the minimum sample size required to show a prevalence of NE of 15.0% was calculated as 2800 respondents. We predicted a response rate of at least 60% and therefore distributed 4700 questionnaires.
Private and government schools in large metropolitan areas, like Johannesburg, Cape Town and Durban were asked to participate and these areas were selected, as they were convenient and easily accessible: The questionnaires were delivered to schools that were prepared to participate. Schools from different socio-economic classes were included, so children from differing socio-economic backgrounds and all race groups were included in the study. The authors did not approach schools in rural areas because this was not feasible, there was a very tight budget and we could not afford to courier questionnaires to the rural areas. As the children in the cities came from diverse cultural and socio-economic backgrounds, the authors believe that the children in this sample group were a good representation of children in South Africa.
A total of 4700 questionnaires were distributed to children at 37 selected schools in Gauteng (n= 21), the Western Cape (n= 6) and KwaZulu-Natal (n= 10). An accompanying letter to the parents requested that they fill out the questionnaire and return it to the school. Instructions were provided as to how these should be completed and returned in an anonymous way.
Returned questionnaires from each province and school were checked twice for children with and without NE. Data consisting of each reply to the questions from completed questionnaires about reported children with NE, were recorded using a Microsoft Excel spreadsheet.
Data were reported as frequencies and percentages in tables and graphs. The chi-squared test was used to compare the prevalence of NE between groups and Fisher's exact test was used to correct for small numbers of observations (n≤ 5). The significance of the differences between age groups was determined using the Student's t test. For all statistics a P value ≤0.05 was considered significant.
Due to limited resources and manpower, schools were selected if they were relatively accessible to the study investigator. Hence, schools in remote areas were excluded and selection was therefore not random. However, our study was powered and the response rate was high.
A total of 3389 questionnaires were returned, giving a response rate of 72.1%.
Overall prevalence of NE, MNE and NE associated with daytime urinary incontinence (DUI) according to age was calculated. Of the 3389 children, 541 were reported as having NE, giving an overall prevalence of 16.0%. Of the latter, 487 children reported having MNE (14.4% overall prevalence) and 54 children reported having NE associated with DUI (1.6% overall prevalence). The age of the children with NE ranged from 5 to 10 years, with an average age (±sd) of 6.5 (±1.4), 6.6 (±1.5) and 6.1 (±1.3) years for the NE group, MNE group and NE associated with DUI group, respectively. Children in the NE associated with DUI group were significantly younger than those in the MNE group (P= 0.011). The prevalence of NE, MNE and NE associated with DUI showed a significant decrease with age (P < 0.001 for all three groups; Table 3).
Table 3. Overall prevalence of nocturnal enuresis in South African children according to age
Age in years
All NE (MNE + NE associated with DUI)
NE associated with DUI only
MNE + constipation
P value for chi-squared test for trend. NE, nocturnal enuresis; MNE, monosymptomatic NE; DUI, daytime urinary incontinence
There was a higher prevalence of MNE among boys than girls with an overall ratio of approximately 1:2 (female : male). Even though this gender difference appeared to diminish with increasing age (Table 3), it did not reach significance (chi-squared test for trend P= 0.17).
The severity of NE episodes is shown in Fig. 2 and were categorized as follows: every night (severe), at least three times per week (moderately severe), once per week (infrequently), once per month, and occasionally (less than once per month). The commonest severity (28.3%) was three or more NE episodes per week.
Overall, 42% of parents with children suffering from MNE in this study were unaware that there are specific treatments available for MNE. There was no significant difference in the awareness of treatment among these parents with children suffering from MNE at different ages.
Overall, 61.3% of parents indicated a willingness to seek treatment for their children's MNE, if the problem did not resolve spontaneously. Figure 3 compares the percentage of children from parents who said they would potentially take them for treatment with the percentage of children actually being treated for MNE. Only 138 (28.3%) of the 487 children identified with MNE were receiving some form of treatment for their MNE. A significant overall difference was shown for the number of children receiving treatment with age (chi-squared test, P= 0.0014). In particular, fewer parents of children aged 5–6 years sought treatment compared with those whose children were aged 7 years and older (chi-squared test, P= 0.0063). The sample sizes in the 9-year-old and 10-year-old age groups were too small to draw meaningful conclusions.
To prevent future episodes of MNE, a total of 138 children received either advice or treatment as listed in Table 4. These results show that the various treatment modalities combined are only 30% effective in children with MNE. Specifically, administering medicine was the most effective with a 45.5% success rate. Conversely, taking no action resulted in no alleviation of the problem.
Table 4. Treatment modalities of children with nocturnal enuresis and their success rates according to parental appraisal
Advice or treatment received
Total number of children with MNE per treatment modality (%)
Number treated successfully (%)
*After parents sought treatment. †Some children received more than one treatment modality. NE, nocturnal enuresis; MNE, monosymptomatic NE; DUI, daytime urinary incontinence.
Of the 138 children with MNE receiving either advice or treatment, 66 of them (48%) were on medicine prescribed by their healthcare providers, of which 45.5% were successfully treated (Fig. 4). Treatment with desmopressin and imipramine had the highest success rates at 74% and 72%, respectively, and conventional drugs were significantly superior to homeopathic remedies (chi-squared test with Yates correction, P= 0.0083).
Possible causative factors of NE were investigated. Parents of 246 of the 487 children with MNE (50.5%) in this study population reported a family history of MNE, i.e. having at least one parent or sibling with a history of MNE. The proportion of children suffering from MNE and having at least one parent or at least one sibling with a history of MNE was 22.4% (n= 109) and 17.7% (n= 86), respectively, compared with 10.5% (n= 51) of children with MNE having at least one parent and one sibling with a history of MNE.
The overall prevalence of children with MNE also suffering from constipation was 15.8%. Table 3 shows the prevalence of constipation in children with MNE according to age. No apparent trend for the prevalence with age was found (chi-squared test, P= 0.82).
The prevalence of stress factors in enuretic children in South Africa, as reported by their parents, showed that most children suffering from MNE had no stress factors (71%), whereas 26% reported having one stress factor and only 3% reported more than one stress factor. The results of a potential link between the MNE in children and the different psychological stress factors as a possible cause of their enuresis are shown in Table 5. Of the 487 children with MNE, 143 (29.4%) were reported to have a link to stress. A total number of 179 stressful events were recorded in these children under the following listings in the questionnaire: serious injury to the child or a family member; illness in the family; violence towards the child of another family member; death in the family; divorced or separated parents; and other factors. The last category contributed to the stress factors in 42.0% of children and included strict parents or teachers, bullying at school, the birth of a sibling and moving house.
Table 5. Stressful events in children with monosymptomatic nocturnal enuresis
Age in years
Total with MNE (n)
Number of children with MNE and link to stress (%)
Serious injury to child or other family member (n)
*‘Other’ refers to events perceived by the parents to be contributing factors and included strict teachers, strict parents, bullying at school, the birth of a sibling and moving house. †The total is the sum of the children whose parents reported a stress factor, some more than one factor, so the total does not equal the number of children with MNE. MNE, monosymptomatic nocturnal enuresis.
This questionnaire-based study had a response rate of 72.1% and included 3389 children. Previous studies from other countries reported similar response rates: Thailand 70.1% ; Italy 77%  and Australia 74% . In keeping with these studies, similar methods were used in the present study to distribute and retrieve questionnaires. This study found an overall prevalence rate of 16% for NE. The latter included children with MNE (14.4% prevalence) and NE associated with DUI (1.6%) and the prevalence rates showed a significant trend for decreasing with age. Previous studies cited in the literature and using the same inclusion criteria to investigate children at the age of 7 years, report a prevalence of NE between 9.5 and 16.4% and a prevalence of MNE between 7.4 and 13.8% [6,12,19]. At this age, the prevalence of NE and MNE in our cohort of South African children was similar to that reported by these studies: 12.3% NE and 11.3% MNE.
In the present study, the overall prevalence of children with NE also suffering from daytime incontinence was 1.6%, which is in keeping with studies from the UK , Korea  and Australia . In contrast, a Turkish study  reported a rate of 21.0%, but there was no apparent reason for this discrepancy.
In this South African cohort, the overall prevalence of NE was greater in boys than in girls (female to male ratio of 1:2), which is similar to the ratio reported in studies from western countries .
The frequency of enuretic episodes varies in children. According to the literature, only 15% of children with NE have an enuretic episode every night, although most children suffering from NE have enuretic episodes more than once a week . This is less than the overall severity of NE episodes in the present study, where 24% of children with NE had enuretic episodes every night and 68% had an episode once a week or more. These results indicate that approximately one-quarter of children suffering from NE in South Africa have severe symptoms.
Significantly, 14% of children aged 5–10 years suffer from MNE in South Africa, of which only 28.3% received some form of treatment or advice. Parents did not seek help and were not enlightened about treatment options for MNE. In this study, 42% of parents reported being unaware of specific treatments available for the treatment of MNE and, as mentioned earlier, our data are in keeping with studies from other countries.
Where 61.3% of parents in our study indicated a possible willingness to take their children for treatment of some kind if the problem did not resolve spontaneously, a substantial 39% indicated that they would not seek treatment. The latter was, however, less than the proportion of unwilling parents from Turkey and Malaysia, where 75% and 87% of parents were unwilling to seek treatment, respectively. Butler et al. also found reluctance in seeking treatment and suggested that this may be because of the perceived high failure rate of treatment of MNE or the feeling that it is socially unacceptable to have this problem.
When we considered the use of behavioural strategies to alleviate MNE episodes in children, our study found that waking the child at night to void urine was most successful, followed by a star chart and fluid restriction. Also, the latter was the most popular behavioural strategy.
In concurrence with other previous studies [6,7,9–13], our study found that, according to parental perception, the administration of medicine was by far the most successful treatment for MNE. Even though only 13.6% of the children with enuresis in our study received medicine as a treatment option, this group showed the highest success rate. Conventional medications, such as desmopressin, imipramine and oxybutynin had similar and high success rates and were significantly more successful than homeopathic remedies according to parents from this study population.
Consistent with previous studies discussed above, our study shows that MNE has a strong tendency to run in families. Overall, 50.5% of the children suffering from MNE in this study had at least one family member, either a parent or sibling, with a history of MNE. However, as there was no significant difference between the proportion of MNE children with or without a family history of enuresis, family history can possibly account for MNE in some, but not all, children from South Africa.
The association between MNE and constipation in this South African cohort was 15.8%. This is lower than previously reported in a Turkish population where 21.6% of children suffered from both MNE and constipation , but our lower incidence may be explained by constipation being overlooked by parents and parents were not questioned in depth about constipation.
Controversy exists as to whether psychological stress factors cause MNE or vice versa. In this study, parents of 29.4% of MNE children perceived that the enuresis could be explained by a possible stressful incident, with the highest prevalence rate found in the 7-year-old group at 37.1%. This indicates that, despite evidence to the contrary, a large proportion of parents still believe that stressful events are the cause of MNE. No significant differences were seen in the reported incidence of stress factors for the different age groups. Notably, the parents of 71% of children in this study reported no psychological stress factors, so such stresses could not be characterized as a causative factor for most enuretic children in South Africa.
In conclusion, this is the first study to estimate the prevalence of NE and report on the parental perception and possible associated factors of enuresis in children from South Africa and trends found were similar to those in other studies. Awareness needs to be created about enuresis. This includes awareness about the condition as well as treatment options.
We thank Ferring (Pty) Ltd (South Africa) for their financial contribution to printing the study questionnaires.