Obstructive Sleep Apnea Syndrome as a Potential Cause of Nocturia in Younger Adults

Abstract

To investigate the impact of age on the relationship between obstructive sleep apnea syndrome (OSAS), nocturia, and other lower urinary tract symptoms (LUTSs). This was a secondary analysis study based on data derived from a previously conducted prospective observational cohort study on OSAS and nocturia. We analyzed 90 subjects who were suspected of having OSAS. Prior to polysomnography, we assessed International Prostate Symptom Score-Quality of Life scores, Overactive Bladder Symptom Scores, and International Consultation on Incontinence Modular Questionnaire-Nocturia Quality of Life scores to evaluate LUTSs. Nocturnal urine volume, night-time frequency, and night-time urine electrolyte content were measured during polysomnography. Patients were divided into groups according to age and OSAS severity determined using apnea-hypopnea index (AHI) scores. Young patients were those aged <65 years and elderly patients, ≥65 years. A multiple linear regression with multiple imputations was performed to examine the association of night-time frequency with demographic, polysomnographic, and clinical characteristics. In young patients, night-time frequency was significantly associated with nocturnal urine volume, AHI score, and total IPSS. However, night-time frequency in elderly subjects was not associated with demographic and polysomnographic characteristics. In order to compare the severity of OSAS, night-time frequency and urinary sodium content significantly increased only in young patients (P=.007 and .004, respectively). OSAS is a strong candidate of causative factor for nocturia in younger individuals. When a younger patient complains nocturia without any urological disorders, OSAS should be kept in mind as a potential cause of nocturia.