Dr. Haruo Nakagawa and colleagues at Tohoku University, Sendai, Japan, followed 784 individuals ranging in age from 70 to 97 at baseline in a comprehensive geriatric-assessment study. Nocturia, defined as two or more voids per night, was present in 359 subjects (45.8%).
During follow-up, 41 fractures occurred, 31 of them related to falls. “The cumulative incidence rate of fracture was significantly higher in individuals with vs without nocturia (26 of 359 or 7.2% vs 15 of 425 or 3.5%),” the researchers report in October’s Journal of Urology.
Also, 35 patients (9.7%) died in the nocturia group compared with 18 (4.2%) in those without nocturia. The mortality hazard ratio adjusted for age and gender was 1.91. This remained almost unchanged (HR 1.95) when further adjusted for possible factors that could increase mortality risk, including BMI, diabetes, smoking status, history of coronary disease, renal disease and stroke, tranquilizers, hypnotics and diuretics.
Dr. Nakagawa and colleagues therefore think that nocturia is not merely a marker of an underlying condition that increases mortality and the risk of fractures. Rather, it could be more directly causative in that interrupted sleep can have negative physiological effects, such as on glucose metabolism and immunity.
It’s also possible that getting up frequently during the night increases the risk of falls, but the team was not able to ascertain the time of day of fall-related fractures.
They conclude by noting that nocturia can be treated, and “studies of the impact of treatment to effectively decrease the frequency of nocturia on the fracture and mortality rates would be of interest.”
Impact of Nocturia on Bone Fracture and Mortality in Older Individuals: A Japanese Longitudinal Cohort Study
J Urol 2010; 184:1413-1418.