Is sleep apnea a risk factor for nocturia?

This study investigated the impact of age and obstructive sleep apnea syndrome (OSAS) on urinary symptoms. Researchers suggested that OSAS might be associated with nocturia (waking up at night to urinate) in younger adults.

OSAS occurs when the throat muscles, such as tongue and soft palate, temporarily relax during sleep. When this happens the throat airway becomes narrowed or closed and the breathing stops temporarily. It leads to poor sleep at night and daytime sleepiness and tiredness. OSAS is a potentially serious sleep disorder that is associated with heart disease and sudden death. Other symptoms associated with OSAS are urinary disorders, such as nocturia.

Nocturia is present in 50 to 70% of patients with OSAS and in 2 to 4% in young aged adults. It is possible that OSAS causes nocturia in younger patients. Therefore, detection and early treatment for OSAS in young patients may be beneficial. However, the impact of OSAS on nocturia in these patients is not clear.

This study included information about 90 patients with OSAS. The urinary symptoms were assessed followed by polysomnography (sleep study – used to diagnose sleep disorders). Young patients were considered those aged less than 65 years and the elderly were the ones aged 65 or older.

In younger patients, night-time urination frequency was associated with nocturnal urine volume. However, night-time frequency in elderly patients was not associated with OSAS. The severity of OSAS was associated with night-time frequency and salt intake in younger patients.  

This study concluded that OSAS might cause nocturia in younger patients.

This study included a small number of participants. Also, the monitors attached to the patients' bodies during the sleep study may have affected their sleep quality. This may have influenced urinary frequency.