Nocturia and overactive bladder in obese women: A case-control study

To estimate the prevalence and severity of nocturia and lower urinary tract symptoms in obese women and to identify risk factors associated with nocturia in an obese population.

We performed a case-control study based on the registry of a university hospital obesity unit. A consecutive sample of women with body mass index ≥30 (obese) was randomly matched by age, gender and residential county to control subjects using the computerised register of the total population. Data were collected by a self-reported postal survey.

The questionnaire was completed and returned by 279/446 of the patients (62%) and 430/892 control subjects (48%). Compared to the non-obese control group, obese women reported a significantly increased prevalence and bother of nocturia (p < 0.001), frequent urination (p < 0.001) and bothersome experience of urination (p = 0.037). Moreover, they experienced significantly increased frequency of urinary urgency (p < 0.001), of urge urinary incontinence (p < 0.001) and of bladder emptying difficulties (p = 0.002). The adjusted odds ratio (95% CI) in obese women was 2.8 (1.0-7.9) for nocturia, 4.7 (1.5-14.6) for frequent urination, 5.5 (1.7-17.2) for strong urge to empty bladder and 7.2 (2.2-23.3) for urine leakage related to the feeling of urgency.

Obese women are at substantially increased risk for nocturia and overactive bladder symptoms.