Family history of nocturnal enuresis and urinary incontinence: results from a large epidemiological study.

PURPOSE: Nocturnal enuresis is a common, genetically heterogeneous disorder. Family, twin and segregation analyses have demonstrated a high heritability. Molecular genetic linkage studies have identified several loci on different chromosomes. Much less is known about the genetics of daytime urinary incontinence. In this study we identify familial patterns in a large, representative sample of children with nocturnal enuresis and daytime urinary incontinence.
MATERIALS AND METHODS: Participants were a cohort of more than 8,000 children enrolled in the population based Avon Longitudinal Study of Parents and Children, a prospective longitudinal study of an original birth cohort of nearly 14,000 children. Parents completed postal questionnaires asking about their own nocturnal enuresis and urinary incontinence. At the age of 7½ years extensive data on nocturnal enuresis and urinary incontinence of their children were obtained.
RESULTS: At the age of 7½ years the prevalence of nocturnal enuresis was 15.5%. Infrequent nocturnal enuresis affected 12.8% of children and severe nocturnal enuresis (2 or more episodes weekly) affected 2.6%. The prevalence of urinary incontinence was 7.8%, and 6.8% had infrequent and 1.0% had severe daytime urinary incontinence. Of the 11,650 mothers who provided data on their own nocturnal enuresis and urinary incontinence 8.8% had nocturnal enuresis and 0.7% had daytime urinary incontinence. Of the 7,897 fathers 9.6% had nocturnal enuresis and 0.3% had daytime urinary incontinence. There were significant associations between parental and child nocturnal enuresis, and parental and child urinary incontinence. Specifically the odds ratios for severe child nocturnal enuresis were 3.63 times higher in maternal and 1.85 times higher in paternal nocturnal enuresis. The odds ratios for severe child urinary incontinence were 3.28 times higher in maternal and 10.1 times higher in paternal urinary incontinence. The associations were less pronounced between parental nocturnal enuresis and child urinary incontinence, as well as between parental urinary incontinence and child nocturnal enuresis.
CONCLUSIONS: Formal genetic risks exist for nocturnal enuresis and urinary incontinence, especially in severe incontinence. The magnitude of effects for child nocturnal enuresis and urinary incontinence is comparable. While the heritability of nocturnal enuresis is well-known, the familiarity of urinary incontinence has been underestimated.