Factors related to the age of attainment of nocturnal bladder control: an 8-year longitudinal study.

The age of attainment of nocturnal bladder control was studied in a birth cohort of New Zealand children. By 8 years of age, but all 3.3% of children had attained such control, but because some children had relapsed subsequent to the attainment of control, 7.4% of children had nocturnal enuresis. It was estimated that from 5 years of age onward between one half to two thirds of children experiencing nocturnal enuresis did so as a result of failure to attain nocturnal control and the remaining children had secondary or onset enuresis. Factors predictive of the age of attainment of nocturnal bladder control were a family history of enuresis, the child's developmental level at 1 and 3 years of age, and the child's early sleeping patterns. The age of attainment of bladder control was unrelated to a broad range of psychosocial factors including family social and economic background, family life-event measures, changes in parents in the family, and residential changes. These results favor the view that the etiology of primary enuresis is mainly biologic and that psychosocial factors play little role in this aspect of bed-wetting.