Prevalent, morbid, and costly ($61 billion/year in 2012), nocturia is a major problem, especially for older adults. It increases the risk of falls, fractures, depression, nursing home placement, and death. Yet management of nocturia remains inadequate. Most behavior and pharmacotherapies for nocturia focus on bladder-related etiologies, and it?s most prevalent attribute nocturnal polyuria (NP), or increased urine production during sleep remains poorly understood and inadequately treated with little advancement over the last 50 years. Disruption of diurnal excretory pattern, with higher nighttime urine production is common in older adults. While studies in young adults show that sleep plays a critical role in regulating nighttime urine production, among older adults the role of poor sleep in NP is under-investigated. Urine production follows a circadian pattern in which transition from wake to sleep is followed by a pronounced decrease in excretion of water, electrolytes and other osmotically active substances. Studies in young population have established that physiological urine production follows a circadian rhythm, which is regulated by diurnal variation in secretion of hormones controlling water and salt excretion such as arginine vasopressin, renin-angiotensin-aldosterone system, and atrial natriuretic peptide. Sleep deprivation blunts nocturnal surge of these hormones and consequently alter water and salt excretion thereby increase nighttime urine volume leading to NP. Recent evidence suggests that poor sleep quality, frequent sleep interruptions especially in the first part of the night and shorter duration of first uninterrupted sleep period are associated with NP but its pathophysiology is not fully understood. Additionally, among older adults with poor sleep, we have shown that a behavioral intervention directed solely towards sleep (BBTI- brief behavioral treatment of insomnia an efficacious multimodal behavioral treatment for insomnia) not only improves sleep, but also nocturia. Hence, we postulate that sleep interruptions in the first part of the sleep impacts the hormonal regulation of nighttime urine production causing NP. In addition, we postulate that interventions to prolong the first uninterrupted sleep period will decrease NP and hence nocturia. The, aims of the present proposal are to: 1) examine the impact of BBTI on duration of the first of uninterrupted sleep period and NP in elderly with nocturia; and 2) establish NP and duration of first uninterrupted sleep as mechanisms by which BBTI impacts nocturia. Our hypothesis is that BBTI improves nocturia not only by improving sleep, (and specifically, duration of the first uninterrupted sleep period), but also by decreasing NP. To accomplish our goals we will recruit 60 community dwelling adults (aged >65) with nocturia and NP. Sleep will be assessed subjectively with the Insomnia Severity Index and objectively by 7-day sleep diary and wrist actigraph. Concurrently we will collect 3-day bladder diary data to document their voiding pattern and volume during day and night. Participants will be randomized to receive the 4-week behavioral sleep intervention BBTI by a trained therapist or an information control intervention. The participants will repeat the study measures post-intervention. The study results will provide important insights into shared pathological mechanisms underlying poor sleep, nocturia and nighttime urine production. We will use these findings to construct a larger R01 to explore in the elderly biological mechanisms of NP, circadian rhythms of hormones regulating salt and water excretion, and the impact of sleep treatment on these rhythms.
Nocturia is prevalent in older adults and it vastly reduces quality of life. Yet its treatment remains inadequate because its causes are not well understood, especially nocturnal polyuria or increased urine production at night. This study, which builds on our ongoing research, would be the first of its kind to explore the role of sleep in nighttime urine production. The findings will contribute important knowledge to guide development of better targeted and more effective therapy for this prevalent and morbid condition.
