Study design, materials and methods
A national questionnaire survey was conducted in 2014. The study population was identified by the Central Bureau of Statistics from the Total Population Register and comprised Swedish women that had not given birth and were 25-64 years of age. Twenty thousand women were randomly invited to participate in this study from the total number of eligible nullipara (n = 625 810). The 20 000 participants comprised four, independent, random samples, stratified by decades of age, with oversampling of the two youngest age groups for a subsequent longitudinal follow-up. The women were invited to answer a 40-item self administered questionnaire (web and postal version) which included questions about urinary or fecal incontinence, genital prolapse, childhood nocturnal enuresis, severity and subjective impact of disorders, treatment, etc. Childhood NE was defined according to the International Childrens Incontinence Society (ICCS). Multivariable logistic regression models were used.
The response rate was 52.2%, lowest (44.7%) in the youngest age group (25-34 years) increasing consistently to 62.4% among the oldest (55-64 years). One or more PFDs occurred in 26.7% (95% CI 25.8-27.7) of NE-negative women and increased to 43.4% (40.3-46.5) in NE-positive women. Correspondingly UI increased from 13.7% (CI 13.0-14.5) to 28.9% (CI 26.1-31.8). The subtypes of UI i.e. urge urinary incontience (UUI) and stress urinary incontinence (SUI) were doubled for UUI from 2.4% (CI 2.1-2.8) to 5.7% (CI4.4-7.3) and for SUI from 5.7%(CI 5.2-6.2) to 10.5% (CI 8.8-12.6) in women without a history of childhood NE compared to women with a history of NE. Mixed urinary incontinence (MUI), the most bothersome subtype of UI, more than doubled from 3.3% (CI 2.9-3.7) in NE-negative women to 8.3% (CI 6.8-10.2) in those with a history of childhood NE. FI and sPOP also nearly doubled in the NE-positive women in comparison to NE-negative women. The effect of BMI was substantial. UI increased nearly more than 5 fold from 11,2% in NE-negative group with normal BMI <25 to 55,7% in NE-positive group with high BMI >35.
Interpretation of results
A history of childhood NE was associated with a doubling of the prevalence of all pelvic floor disorers (PFDs) compared with nullipara without NE. One or more PFDs occurred in 26.7% of NE-negative women but increased to 43.4% for NE-positive women.