MATERIALS AND METHODS

Participants were children age 5 to 11 recruited while visiting the Primary Health Care clinics; children with known neurological and genetic syndromes were excluded.

The study was conducted by requesting that parents complete a questionnaire on their child's history with urinary and other behaviors. The questionnaire was purpose-built for this research by the author and was subsequently validated by the Hamad Medical Corporation (HMC) Research Committee. This study was approved by HMC ethics committee.

The questionnaire consisted of three parts where the first part included socio-demographic characteristics and toilet training of the sample. The second part was designed to enquire about the presence of nocturnal enuresis and its relevant characteristics. Children without NE were asked about the age of dryness. The third part of the questionnaire asked all participants about psychological and medical conditions such as constipation, snoring, and the experience of stressful events. Sleep disturbances are defined by the ICD-10 such as nightmares, sleep terrors, sleep walking, and sleep talking.

Constipation was defined as delay or difficulty in defecation, present for two or more weeks and sufficient to cause distress to the patient. (4,5)

The questionnaire was not based on the Screening Instrument for Psychological Problems because ADD and ADHD subjects were not part of the study. The questionnaires were not validated as the Vancouver or Toronto voiding questionnaires.

Statistical Analysis: Qualitative and quantitative data values were expressed as frequency along with percentage and mean±SD. Descriptive statistics were used to summarize demographic and all other clinical characteristics of the participants. The prevalence of nocturnal enuresis was estimated and presented along with 95% CI. Associations between two or more qualitative variables were assessed using chi-square test, chi-square test with continuity correction factor or Fisher exact test as appropriate. Quantitative variables data between two independent groups (nocturnal enuresis and nocturnal continence) were analyzed using unpaired 't' test. The results were presented with the associated 95% confidence interval. Univariate and multivariate logistic regression analysis was carried out to assess the association of various potential factors and predictors such as age at diurnal dryness, age at nocturnal dryness, age when child started toilet training, gender, family size, family history enuresis, nocturnal dryness, suffer constipation, fecal incontinence, stressful events, snoring and other medical problems with outcome variable nocturnal enuresis. Logistic regression analysis results were presented in terms of odds ratio (OR) and associated 95% CI. A two-sided P value <0.05 was considered to be statistically significant. All Statistical analyses were done using statistical packages SPSS 22.0 (SPSS Inc. Chicago, IL).

There were 399 participants in the study; 145 (36.3%) were nocturnal enuresis, 254 (73.7%) participants were nocturnal continence. Mean age at diurnal dryness in the nocturnal enuresis group was significantly higher 30.7±7.8 years, compared to nocturnal continence group 27.9±7.4 years (P<0.001). Similarly, the mean age at nocturnal dryness (40.6±14.8 vs 34.4±10.1; P=0.004), age when child started toilet training (25.8±6.9 vs 23.8±6.9; P=0.006) in the nocturnal enuresis group was significantly higher compared to nocturnal continence group respectively.

Surprisingly, we found that 36.3% of children suffered from enuresis, while the remaining subjects didn't suffer from enuresis. This was based on analyzing data collected from 399 patients at Al Rayyan and Abu Baker primary health care centers, of which 84 (59%) were male (Table 2). Of all participants, the age when the child started toilet training was 24.6 months on average; diurnal dryness was achieved at age 28.9 months (±7.6), and nocturnal dryness was achieved at 35.5 months (±11.4) (Table 1).

The prevalence of nocturnal enuresis and their association with demographic, physiological, and other medical and clinical characteristics are shown in Table 2. The overall prevalence of nocturnal enuresis was 36.3% (95% CI: 31.6 to 41.1). The prevalence of nocturnal enuresis in the positive family history of enuresis was significantly higher 97/172; 56.4% compared with 48/227; 21.1% (P<0.001) in the nocturnal continence group. Significantly higher nocturnal enuresis prevalence occurred among children who presented with non-nocturnal dryness (87.6% vs 16.1%; P<0.001) compared to nocturnal dryness. Similarly children experiencing stressful events had significantly higher nocturnal enuresis compared with children with stressful events (56.3% vs 17.9%; P<0.00). Also, children with other medical problems showed a similar trend with significantly higher occurrences of nocturnal enuresis, P<0.001. Gender, age at diurnal dryness, family history, did not have any significant association with nocturnal enuresis as presented in Table 2.

The results of logistic regression analysis testing for each predictive variable and factors and their association with nocturnal enuresis are presented in Table 2. The results were presented with odds ratio (OR) and associated 95% confidence interval (CIs). Logistic regression analysis revealed that increasing age at nocturnal dryness, age when child started toilet training, family history enuresis, nocturnal dryness, suffer constipation, fecal incontinence, stressful events, snoring and other medical problems were common risk factors and predictors significantly associated with an increased risk for nocturnal enuresis. Risk of nocturnal enuresis was 2.6 times likely to be higher among children having age at nocturnal dryness more than 40 months (unadjusted OR 2.6, 95% CI 1.37-4.94; P=0.003) compared to age group less or equal to forty months. Children who had positive family history of enuresis were nearly 4.8 times as likely to have more risk for nocturnal enuresis (unadjusted OR 4.82, 95% CI 3.11-7.48; P<0.001). Children who had nocturnal enuresis were nearly 1.7 times as likely to suffer from constipation (unadjusted OR 1.68, 95% CI 1.0-2.82; P=0.05), 3.1 times as likely to be positive for fecal incontinence (unadjusted OR 3.06, 95% CI 1.09-8.61; P=0.034), 5.9 times as likely to have stressful events (unadjusted OR 5.91, 95% CI 3.75-9.32; P<0.001), 4.2 times as likely to have sleep disturbance and 3.4 times more likely to have other medical problems, than those who had nocturnal continence. Children with enuresis were twice as likely to snore than children without enuresis (unadjusted OR 2.1, 95% CI 1.29-3.78; P=0.003).

Children with enuresis were almost 8 times more likely to have worms than children without enuresis (unadjusted OR 7.9, 95% CI 4.19-15.14; P<0.001).

Using multivariable logistic regression analysis controlling for all other potential predictors and factors such as age at diurnal dryness, age at nocturnal dryness, age when child started toilet training, gender, family size, family history enuresis, suffer constipation, fecal incontinence, stressful events, snoring and other medical problems we found that the factors with the strongest and significant association with nocturnal enuresis are children having positive family history of enuresis, nocturnal dryness, stressful events and sleeping disturbance or snoring. No significant interactions were found between different potential factors and predictors considered above and including an interaction terms in the model, had no effect on the adjusted odds ratio as shown in Table 3.

Most parents were assisting their children when they bed wet (64); 43 blamed the child and 6 spanked the child (Table 1). At the follow up evaluations at 6, 12, and 18 months where the number of children with enuresis reduced from 102 children to 97 and 75 respectively (Table 4).

Table 1: Baseline Demographic, Physiological and other Clinical Characteristics


Table 2: Association of various predictors with nocturnal enuresis: Univariate Logistic regression analysis
CI: Confidence interval; OR: odds ratio; †Subjects in this category served as the reference group.
The sum may not equal to n=399 for some variables due to some missing data.

Table 3. Association of various predictors with nocturnal enuresis: Multivariate Logistic regression analysis

CI: Confidence interval; †Subjects in this category served as the reference group.
The sum may not equal to n=399 for some variables due to some missing data.

Table 4: Follow-up outcome measures

DISCUSSION AND CONCLUSIONS

In our study, we found a high prevalence and an unexpectedly high percentage of nocturnal enuresis (36.3%) with equal distribution in both sexes. In similar studies carried out in Jordan and Yemen, the prevalence of Nocturnal Enuresis among 5 to 15 years old children was reported as 8.8% to 28.6% respectively (6, 7). The prevalence found in this study was higher than reported worldwide, at 8.3 - 12.3% (9). This difference could be explained due to the high number of 5 and 6-year old participants in our study which also explains the reduction in the numbers found also at the follow up evaluations at 6, 12, and 18 months where the number of children with enuresis reduced from 102 (25%) children to 97 (24%) and 75 (19%) respectively. At this age, the rate of resolution worldwide is usually reported at 15% per year (9).

Stressful events and sleep disturbances were significantly higher in the children with enuresis compared with those without enuresis - 74.5% vs. 33.1% , p < .0001, and 54.5 % vs22 % p <0001 respectively. Worldwide the overall rate of comorbidity in epidemiological and in clinical studies are approximately: 13.5%-40.1% of all wetting children have clinically relevant behavioral problems (9), emphasizing the importance of taking a thorough history of sleep disturbances such as nightmares, sleepwalking, sleep talking, and stressful events like mother deprivation, school failure, and siblings' rivalry. It is helpful to support the family and children in these cases with follow up even without excellent outcome of the treatment,; (10) when necessary, patients should be referred to the appropriate professionals for related conditions.

Medical problems (e.g., UTI, bronchial asthma) were found to be higher in the children with enuresis compared to the control group (unadjusted OR 3.37, 95% CI 2.18-5.21; P<0.001) while intestinal worms in children in enuresis were also found to be higher (unadjusted OR 7.9, 95% CI 4.19-15.14; P<0.001) These children may benefit from medical treatment. Of course, treatment of intestinal worms will reduce one of the child's sufferings but it is not known whether this contributes to the resolution of enuresis or not.
It was found that 34 children with enuresis also were snoring (unadjusted OR 2.1, 95% CI 1.29-3.78; P=0.003). On the other hand 31 children without enuresis were also snoring. We don't know whether future treatment of snoring will improve bedwetting as was found in another study where half of the children tonsillectomised had improvement of their enuresis (8).

During the 3 follow ups (6, 12, and 18 months), spontaneous recovery was observed. Recovery rates of 26, 24, and 19% were observed after 3 times follow-up at 6, 12, and 18 months respectively. Interestingly, there were several new cases of children without enuresis starting to bed wet (likely from secondary enuresis), which should prompt a clinician to investigate and treat possible causes.

We recommend that clinicians obtain a thorough family, genetic, trauma, stressful events, and toilet-training history; conduct a physical examination; and perform urine and stool analysis and cultures, urine 24-hour osmolarity, and blood sugar tests. Abdominal and pelvic ultrasounds would be useful for suspected congenital malformation. Nocturnal enuresis is a benign condition, and its complications can often be resolved with special care and treatment.

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