Abstract General Information

Title

ESTABLISHMENT OF NOCTURNAL BLADDER CONTROL AND BEHAVIORAL SEXUAL DIMORPHISM IN CHILDREN

Introduction and objective

Gender difference in establishment of bladder control has been reported, though exact mechanism of the difference is obscure. There is dimorphic brain development between genders as well as anatomical difference. Because establishment of bladder control would be affected by development of central nerve system, impact of sexual dimorphic brain development on establishment of nocturnal bladder control was investigated.

Method

Among participants in national birth cohort study “Japan Environment and Children’s Study (JECS)”, survey sheets including Pre-school Activities Inventory (PSAI) and night-time wetting (NTW) were sent to 1503 children’ mothers who agreed to participate in the adjunct study of “Effect of Maternal Exposure to Endocrine-disrupting Chemicals on Sex Development and Gonadal Function” when children became 3 years old between October 2015 and December 2017. PSAI is a questionnaire in which parents indicate their child’s involvement in various sex-type behaviors and in which higher scores was designed to represent masculine-typical behavior. Relationship between status of NTW and score of PSAI were investigated using Chi square test, Student’s t test and linear regression analysis.

Results

Among 990 children who returned the survey sheets (65.9%), 818 children (435 boys and 383 girls) who were born as singleton and whose score of PSAI and status of NTW at 37 to 39 months of age as well as their background data from JECS were available were enrolled in the present study.
Presence of NTW during a month tended to be higher in boys (80.2%) than girls (75.2%) (p=0.092). Score of PSAI was significantly higher in boys (56.8+/-8.2) than in girls (29.4+/-8.6) (p<0.0001). Frequency of NTW per week was classified as 4 days or more, less than 4 days or none. Score of PSAI in girls with NTW for 4 days or more was significantly higher than those without NTW (30.7+/-8.6 vs 28.0+/-8.3, p=0.017). A linear regression analysis revealed a positive relationship that as frequency of NTW increased, score of PSAI was higher in girls even after adjusted by presence of elder sisters or elder brothers or age at survey (β(95%CI): 0.013 (0.003, 0.022), p=0.001). These difference were not observed in boys.

Conclusion

The present study demonstrated that establishment of nocturnal bladder control was related to behavioral sexual dimorphism in girls. These findings suggest that factors affecting developing sexual dimorphic brain development may also affect the establishment of nocturnal bladder control.