The association between nocturia, hormonal symptoms and bladder parameters in women: an observational study

Postmenopausal nocturia is poorly understood. This study aimed to identify hormonal and lifestyle factors associated with nocturia and to understand the relative contribution of altered urine production and bladder storage dysfunction in women.

Women ≥40 years presenting to public continence services were enrolled in a cross-sectional study. A total of 153 participants completed a hormone status questionnaire, a validated nocturia causality screening tool and a 3-day bladder diary. Descriptive statistics and logistic regression models for nocturia severity and bladder diary parameters were computed.

Overall, 91.5% reported nocturia, 55% ≥2 /night. There was a difference of 167.5 ml (P < 0.001) in nocturnal urine volume between women with nocturia ≥2 (median 736 ml) versus less often (517 ml). Significant predictors of self-reported disruptive nocturia were age (odds ratio [OR] 1.04, 95% CI 1.002-1.073) and vitamin D supplementation (OR 2.33, 95% CI 1.11-4.91). Nocturnal polyuria was significantly more common with nocturia ≥2 compared with less frequent nocturia (P < 0.002). Exercise for 150 minutes a week was protective for nocturnal polyuria (OR 0.22, P = 0.001). Nocturia index >1.3 was significantly predicted by age (OR 1.07, P < 0.001), regular exercise (OR 0.41, P = 0.036), day flushes (OR 4.00, P = 0.013) and use of vitamin D (OR 2.34, P = 0.043). Maximum voided volumes were significantly lower with nocturia ≥2 versus less often (night: 268 ml versus 350 ml; day: 200 ml versus 290 ml).

Bothersome nocturia in postmenopausal women is associated with changes to both nocturnal diuresis and bladder storage. Regular physical activity, prolapse reduction and oestrogen replacement may be adjunctive in managing bothersome nocturia in women.