A population study of nocturia in Singapore

OBJECTIVE: To estimate the prevalence of nocturia in the multiracial Asian population of Singapore, using the new International Continence Society standardized definition of one or more voids per night, and to assess its associations, bothersomeness and impact on sleep. SUBJECTS AND METHODS: A door-to-door interview questionnaire survey was conducted amongst a randomly selected sample of 3000 individuals (response rate 78.2%). Nocturia and its associated problems were evaluated using questions from the International Prostate Symptom Score (IPSS), and concurrently, sociodemographic and health variables were recorded. RESULTS: Data from 1134 women (aged 20-95 years) and 1139 men (aged 20-92 years) were analysed; the overall prevalence of nocturia (one or more voids/night) was 55.5%, with an increasing proportion in older groups (P < 0.01). Women had nocturia significantly (P = 0.015) more often than men (58% vs 53%), and it was positively associated with poor health, with the highest odds ratios (95% confidence interval) for diabetes mellitus of 2.0 (1.3-3.1), for renal disease of 6.4 (2.3-18.2), and for strokes of 3.1 (1.1-9.2). In both men and women, the median IPSS in patients with nocturia was significantly higher than that in patients without nocturia (P < 0.001). For individuals waking once a night, only 9.5% considered nocturia a problem and 13.5% complained of sleep disturbances; these values increased to 36% and 40% for individuals waking up twice or more /night. CONCLUSION: Nocturia is a common condition amongst Singaporean adults, especially in the elderly; it has strong associations with poor health and other lower urinary tract symptoms. The degree of nocturia determines whether patients are likely to be bothered by it or have sleep disturbance, which will influence their help-seeking behaviour.