Aims A pilot survey shows that primary nocturnal enuresis (PNE) prevalence has increased significantly during the past decade in Mainland China. Whether it is related to the delay of elimination communication (EC) is unclear. This study retrospectively investigated the influence of delayed EC on the PNE prevalence in children and adolescents in mainland China. Methods A cross-sectional study of PNE prevalence was performed by distributing 19 500 anonymous self-administered questionnaires to parents in five provinces of mainland China from July 2017 to October 2017. The questionnaires included sociodemographic data, family caregivers' information, and details about the disposable diapers (DD) usage, EC commencement date, psychological disorders, lower urinary tract symptoms, and family history of PNE in children and adolescents. The 2017 PNE prevalence was compared with that of 2006 in Mainland China. Results The total response rate was 97.04% (18 631 of 19 500) and 92.39% (18 016 of 19 500) qualified for statistical analysis. The PNE prevalence in 2017 has increased significantly compared to that of 2006 (7.30% vs 4.07%, P < 0.001). The PNE prevalence in children with EC starting before 6 months of age was significantly lower than those who start after 12 months of age. The longer DD were used and the later the beginning of EC, the higher the PNE prevalence was found. Conclusions The PNE prevalence in Mainland China has increased significantly during the past 10 years. A longer use of DD and later onset of EC may be risk factors for PNE.

Objective To explore the effect of using disposable diaper (DD) on the prevalence of pediatric bladder and bowel dysfunction (BBD ) and analyze the relevant-factors .Methods From March 2017 to September 2017 ,37 primary schools and kindergartens were randomly selected from the municipalities of Shenzhen , Xiamen and Zhengzhou . An anonymous epidemiological survey of using DD from birth and status of voiding and defecation was conducted for 8950 children aged 2 to 8 years .The number of surveyed students was over 200 at each institution .A retrospective survey was conducted by parents recalling past events and filling out questionnaires .For ensuring the accuracy of questionnaires ,the investigators were specially pre-trained .The main contents of questionnaire include general profiles ,whether using DD from birth ,age of stopped using DD ,duration of daily use (fullday or night-only use) , start time of elimination communication (EC) (including potting training , assistant infant's toilet training ) , whether current status of voiding and defecation fulfilling the diagnostic criteria for BBD and presence or absence of organic diseases affecting voiding and defecation .Results A total of 8026 valid questionnaires were collected and analyzed . Statistical analysis of t-test and chi-square test indicated that the overall prevalence of BBD in children surveyed was 2 .73％ and the prevalence of BBD declined with advancing age from 4 .89％ at age 2 to 0 .85％ at age 8 (P< 0 .001) .With the delayed use of disposable diapers and the prolonged daily use of DD ,the prevalence of BBD showed a rising trend (P< 0 .05) .The prevalence of BBD children stopping using DD within the first 6 months of birth was 0 .95％ and the prevalence of BBD in children stopped using DD after an age of 2 years was 6 .11％ .With a delayed start of elimination communication (EC) ,the prevalence of BBD gradually increased ( P < 0 .001 ) . The prevalence of BBD in children starting elimination communication (EC) within 6 months of birth was 0 .91％ and elimination communication (EC) began after an age of 2 years .The prevalence of childhood BBD was 6 .47％ .The multivariate logistic regression analysis of prevalence of BBD revealed that age of stopping using DD ,whole-day use of DD and obesity were risk factors for an onset of childhood BBD (OR > 1 , P< 0 .05) .Starting toilet training within 6 months was a protective factor for childhood BBD (OR < 1 ,P< 0 .05) .Conclusions Rational usage of DD and early start of EC are effective for preventing BBD in children .