Prevalence and factors associated with overactive bladder and stress urinary incontinence in the Japan Nurses' Health Study.

OBJECTIVE

In this study, we aimed to investigate the prevalence and factors associated with urinary symptoms using cross-sectional data from the Japan Nurses' Health Study, a prospective cohort study among female nurses.

METHODS

A total of 12,198 women were included. We calculated the prevalence of urinary symptoms. Odds ratios with 95% confidence intervals were estimated to determine the odds for overactive bladder (OAB), stress urinary incontinence, and mixed urinary incontinence.

RESULTS

The mean age and body mass index (standard deviation, range) were 46.5 (±8.1, 27-82) years and 22.1 (±3.1, 12.9-44.6) kg/m2, respectively. The prevalence of OAB was 9.5% (OAB with urinary incontinence [-wet]: 5.4%, OAB without urinary incontinence: 4.1%), that of stress urinary incontinence (without OAB-wet) was 13.9%, and that of mixed urinary incontinence was 2.1%. Multivariable-adjusted logistic regression analysis showed a significant association between OAB and age 45 to 54 years, and postmenopausal status was moderately associated with OAB in that analysis. In the multivariable-adjusted model, age groups 45 to 49 and 50 to 54 years, body mass index 23-27.4 and ≥ 27.5 kg/m2, and parous status were significantly associated with stress urinary incontinence (without OAB-wet).

CONCLUSIONS

This study showed a significant association of OAB with ages 45 to 54 years and postmenopausal status. Further studies should consider the association between time since menopause and OAB symptoms in the perimenopausal period. A high body mass index and parous status are strongly associated with stress urinary incontinence, and stress urinary incontinence symptoms may become less frequent after menopause.