Impact of Nocturia on Bone Fracture and Mortality in Older Individuals: A Japanese Longitudinal Cohort Study

Purpose: We evaluated the association of nocturia with fracture and death in a large, community based sample of Japanese individuals 70 years old or older. Materials and Methods: The baseline in this population based study was determined in 2003 by an extensive health interview with each participant. In this study we followed 784 individuals with a mean +/- SD age of 76.0 +/- 4.6 years (range 70 to 97). Information on mortality and fracture during the study period was provided by the National Health Insurance system and details on fractures were collected from medical records. We compared the risk of bone fracture and death with or without nocturia in a multivariate Cox proportional hazard model. Results: Nocturia (2 or greater voids per night) was present in 359 of the 784 participants (45.7%). Fracture was observed in 41 cases, including 32 fall related cases. For all fractures and fall related fractures with nocturia the HR was 2.01 (95% CI 1.04-3.87) and 2.20 (95% CI 1.04-4.68, each p = 0.04). Death occurred in 53 cases. The mortality rate in individuals with nocturia was significantly higher than in those without nocturia. For mortality in patients with nocturia the age-gender adjusted HR was 1.91 (95% CI 1.07-3.43, p = 0.03). Even when further adjusted for diabetes, smoking status, history of coronary disease, renal disease and stroke, tranquilizers, hypnotics and diuretics, the positive relationship was unchanged (HR 1.98, 95% CI 1.09-3.59, p = 0.03). Conclusions: During a 5-year observation period elderly individuals with nocturia were at greater risk for fracture and death than those without nocturia.