BACKGROUND:Nocturia (voids arising from sleep) is a ubiquitous phenomenon reflecting many diverse conditions but whether it has significance in its own right remains uncertain. We examined whether nocturia was an independent risk factor for mortality METHODS: These were observational analyses employing primarily North American and European participants and included 7343 men, aged 50-75 years participating in the REDUCE (Reduction by Dutasteride of Prostate Cancer Events) trial. Cox proportional hazards models were used to test the association between baseline nocturia (voiding ≥3 times per night) and all-cause mortality. Potential confounding variables included: age; race; region of origin; treatment group; self-reported coronary artery disease, diabetes mellitus, hypertension, and peripheral vascular disease; smoking; alcohol use; prostate volume; and diuretics. Self-reported sleep quality, as measured with the Medical Outcomes Study sleep scale, was entered as a final step in the model. RESULTS:Nocturia was associated with increased mortality risk (hazard ratio [HR] = 1.72; 95% CI 1.15-2.55) independent from demographics and medical comorbidities. Inclusion of disturbed sleep in the model reduced the magnitude of the association (HR = 1.43; 95% CI 0.93-2.19). CONCLUSIONS:Although the findings are limited to men, half of whom ingested dutasteride, the interruption of sleep by nocturia may have long-term impact on health and may warrant targeted intervention.