Is frequent nocturnal sweating a symptom of obstructive sleep apnea?

Abstract

Aims: To estimate the prevalence and characteristics of frequent nocturnal sweating in subjects with obstructive sleep apnea (OSA) compared to the general population and to evaluate possible changes with positive airway pressure (PAP) treatment.

Methods: The Icelandic Sleep Apnea Cohort consisted of 822 newly diagnosed OSA subjects, referred for treatment with PAP. Of these, 700 subjects were also assessed at a 2 year follow-up. The control group consisted of 703 randomly selected general population subjects. Subjective reporting of nocturnal sweating was assessed on a frequency scale of 1 - 5: (1) never or very seldom, (2) less than once a week, (3) once to twice a week, (4) three to five times a week, (5) every night or almost every night. All OSA patients had a type 3 sleep study. Full PAP treatment was defined objectively as use ≥4 hrs./day and ≥5 days/week.

Results: Frequent nocturnal sweating (≥ 3x a week) was reported by 31.1% of the OSA cohort vs. 11.1% of the general population cohort (p < 0.0001). This difference remained significant after adjustment for demographic factors (age, gender, body mass index, current smoking, hypertension, diabetes and cardiovascular disease). Nocturnal sweating was related to younger age, presence of cardiovascular disease and hypertension, subjective sleepiness, and insomnia symptoms. The prevalence of frequent nocturnal sweating decreased with full PAP treatment (from 33.2% to 11.5%, p < 0.003 compared to the change in non-users).

Conclusion: The prevalence of frequent nocturnal sweating was three-fold higher in untreated OSA patients than in the general population and decreased to general population levels with successful PAP therapy.