Sleep related problems and urological symptoms: testing the hypothesis of bidirectionality in a longitudinal, population based study

Abstract

Purpose: We evaluate the bidirectional association between urological symptoms (urinary incontinence, lower urinary tract symptoms and nocturia) and sleep related variables.

Materials and methods: Data were obtained from a prospective cohort study of 1,610 men and 2,535 women who completed baseline (2002 to 2005) and followup (2006 to 2010) phases of the BACH (Boston Area Community Health) Survey, a population based random sample survey. Sleep restriction (5 hours or less per night), restless sleep, sleep medication use and urological symptoms were assessed by self-report. Urinary incontinence was defined as weekly leakage or moderate/severe leakage, lower urinary tract symptoms (overall, obstructive, irritative) were defined by the AUA-SI (American Urological Association symptom index) and nocturia was defined as urinary frequency 2 or more times per night.

Results: At the 5-year followup 10.0%, 8.5% and 16.0% of subjects newly reported lower urinary tract symptoms, urinary incontinence and nocturia, respectively, and 24.2%, 13.3% and 11.6% newly reported poor sleep quality, sleep restriction and use of sleep medication, respectively. Controlling for confounders, the odds of urological symptoms developing were consistently increased for subjects who reported poor sleep quality and sleep restriction at baseline, but only baseline nocturia was positively associated with incident sleep related problems at followup. Body mass index, a potential mediator, reduced selected associations between sleep and incident urinary incontinence and irritative symptoms, but C-reactive protein did not.

Conclusions: These data suggest that self-reported sleep related problems and urological symptoms are linked bidirectionally, and that body mass index may be a factor in the relationship between sleep and the development of urological symptoms.

Keywords: BMI; BPH; C-reactive protein; CRP; LUTS; SES; UI; benign prostatic hyperplasia; body mass index; cohort studies; epidemiology; lower urinary tract symptoms; sleep; socioeconomic status; urinary incontinence; urologic diseases.

Figure 1. Multivariable Regression Models of Sleep Variables Predicting Incident Obstructive and Irritative LUTS Symptoms, BACH Survey (2002–2010)

Exposures (sleep) were assessed at baseline. Black boxes represent ORs obtained from multivariable logistic regression models with incident urologic symptoms[(a) obstructive symptoms; (b) irritative symptoms] predicted by the sleep exposure variable and controlling for age, sex, race, SES, diabetes, heart disease, alcohol use, physical activity, smoking, anti-depressant use, secondary sedation, and secondary stimulation. Grey boxes represent ORs obtained with further adjustment for BMI. Note: Multivariable logistic regression models for sleep restriction does not control for sex as this measure is collected only in men.

Figure 2. Multivariable Regression Models of Irritative and Obstructive LUTS Symptoms Predicting Incident Sleep Variables, BACH Survey (2002–2010)

Exposures (LUTS) were assessed at baseline. Black boxes represent ORs obtained from multivariable logistic regression models with incident sleep disorders[(a) poor sleep quality, (b) sleep restriction, (c) sleep medication] predicted by the urologic symptom exposure variable and controlling for age, sex, race, SES, diabetes, heart disease, alcohol use, physical activity, smoking, anti-depressant use, secondary sedation, and secondary stimulation. Grey boxes represent ORs obtained with further adjustment for BMI. Note: Multivariable logistic regression models for sleep restriction does not control for sex as this measure is collected only in men.