The association between daytime sleepiness and sleep-disordered breathing in NREM and REM sleep.
BACKGROUND
Daytime sleepiness is common in patients with sleep-disordered breathing. Although respiratory events during sleep are associated with the occurrence of daytime sleepiness, the differential impact of these events during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep on daytime sleepiness has not been well characterized.


OBJECTIVE
To determine the effect of respiratory events during REM sleep and NREM sleep on daytime sleepiness, as assessed by the multiple sleep latency test (MSLT).


METHODS
Cross-sectional study.


METHODS
University-based sleep disorders laboratory.


METHODS
Patients referred for polysomnography and daytime MSLT (n=1,821).


METHODS
N/A.


RESULTS
The study sample was initially divided into quartiles based on the level of the apnea-hypopnea index (AHI) during NREM sleep. Within the first NREM-AHI quartile (NREM-AHI < 8.3 events/hr), the association between REM-related respiratory events and daytime sleepiness was examined using the method of Kaplan-Meier analysis and Cox proportional hazards regression. After adjusting for age, gender, body mass index, and the duration of NREM and REM sleep, REM-AHI was not associated with daytime sleepiness (Relative Risk: 1.01; 95%CI: 0.94-1.10). Similarly, no significant association was observed between REM-AHI and the MSLT in patients within the second through fourth NREM-AHI quartiles. In contrast, increasing severity of disordered breathing during NREM sleep was associated with daytime sleepiness. For a 10-point increase in NREM-AHI, the adjusted relative risks for daytime sleepiness in the second through fourth NREM-AHI quartile were 1.21 (95%CI: 1.01-1.46), 1.20 (95%CI: 1.05-1.37), and 1.10 (95%CI: 1.04-1.16), respectively.


CONCLUSIONS
Sleep-disordered breathing during NREM sleep, but not REM sleep, is associated with increased risk of daytime sleepiness.
Punjabi
Naresh M
NM
naresh@jhmi.edu
Bandeen-Roche
Karen
K
Marx
Jason J
JJ
Neubauer
David N
DN
Smith
Philip L
PL
Schwartz
Alan R
AR
D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D006970:Disorders of Excessive Somnolence / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D012895:Sleep, REM / Q000502:physiology*