An Italian epidemiological multicentre study of nocturnal enuresis

To estimate the prevalence of enuresis in schoolchildren in Italy.

The Italian Club of Nocturnal Enuresis promoted a prevalence study of nocturnal enuresis using a self-administered questionnaire in seven cities in Northern, Central and Southern Italy. The association between enuresis and potential risk factors, e.g. a family history of enuresis, stress, socio-economic status and abnormal diurnal voiding habits, was investigated. The perceived impact on the child and on the family was also evaluated. A random-cluster sampling scheme was used to obtain a sample of primary and secondary schoolchildren from each city. One primary school and one secondary school for each socio-economic level was sampled in each city, giving a total of 42 schools surveyed; 9086 children were covered by the survey. In a cluster sampling method, the variance of prevalence is divided into two components, binomial and extra-binomial variability. Both the DSM III and DSM IV definitions of enuresis were used because at present, there is no consensus on the diagnostic criteria.

Completed questionnaires were received from 7012 children, an overall response rate of 77.2%. Those aged 6-14 years were analysed, restricting the sample to 6892 children. There were 250 enuretic children using the DSM III definition of enuresis and 112 using the DSM IV definition. The overall prevalence was 3.88% and showed a decreasing trend with increasing age. Bedwetting was more frequent in boys than in girls. The prevalence of enuresis was higher when the child was from a family of low socio-economic status despite the child's age group. The logistic analysis showed that familiality, stress, birthweight, age of attaining diurnal continence, soiling and, for girls, menstruation, were statistically significant variables and thus contributed to predicting the probability of bedwetting, confirming the findings of previous studies. There was a large difference in prevalence using the two DSM definitions; a high percentage of DSM III enuretic children had more than two wet nights per week.

It is important that a consensus about the 'working definitions' of enuresis is reached to avoid bias in the recruitment step, to carry out comparable epidemiological studies and to obtain adequate therapeutic responses.