People with nocturia tend to be older and have more comorbid conditions than those without (reference 15 in article). Therefore, when estimating if nocturia is a risk factor for mortality, the effect of confounders must be considered carefully. This prospective, observational Nagahama Study by Funada et al explored the association between nocturia and mortality. While 5 of 11 (45%) earlier studies on this topic were conducted in men only (reference 5 in article), this Japanese study benefited from including both genders. Overall, the results of this study are in line with the findings of a recent systematic review and meta-analysis (including 19,590 men and 14,241 women with a total followup of 297,379 person-years) that found moderate quality evidence for nocturia as a prognostic factor of mortality (risk ratio 1.27, 95% CI 1.16e1.40) (reference 5 in article). The new study has many strengths, including 1) accurate assessments of nocturia with a validated questionnaire, 2) minimization of missing data at followup through time to event based analyses, 3) adequate adjustments to take into account the effect of several confounding factors, 4) testing of exposure-response relationship, and 5) use of time dependent analyses to take the effects of persistent and fluctuating nocturia at followup into account (reference 5 in article). However, as with many earlier studies, this study used opportunistic recruitment, which may yield a sample inadequately representing the general population. Overall, the study contributes to the existing moderate quality evidence of nocturia as a prognostic factor for mortality. However, there is only very low quality evidence supporting nocturia as a cause of mortality.