Using difficulty resuming sleep to define nocturnal awakenings
Received 30 April 2009; received in revised form 7 November 2009; accepted 19 November 2009.
Abstract
Objective
Nocturnal awakenings are one of the most prevalent sleep disturbances in the general population. Little is known, however, about the frequency of these episodes and how difficulty resuming sleep once awakened affects subjective sleep quality and quantity.
Method
This is a cross-sectional telephone study with a representative sample consisting of 8937 non-institutionalized individuals aged 18 or over living in Texas, New York and California. The interviews included questions on sleeping habits, health, sleep and mental disorders. Nocturnal awakenings were evaluated according to their frequency per week and per night, as well as their duration.
Results
A total of 35.5% of the sample reported awakening at least three nights per week. Of this 35.5%, 43% (15.2% of the total sample) reported difficulty resuming sleep once awakened. More than 80% of subjects with insomnia symptoms (difficulty initiating or maintaining sleep or non-restorative sleep) also had nocturnal awakenings. Difficulty resuming sleep was associated with subjective shorter sleep duration, poorer sleep quality, greater daytime impairment, greater consultations for sleep disturbances and greater likelihood of receiving a sleep medication.
Conclusions
Nocturnal awakenings disrupt the sleep of about one-third of the general population. Using difficulty resuming sleep identifies individuals with significant daytime impairment who are most likely to seek medical help for their sleep disturbances. In the absence of other insomnia symptoms, nocturnal awakenings alone are unlikely to be associated with daytime impairments.
aStanford Sleep Epidemiology Research Center, Stanford University School of Medicine, Stanford, CA 94303, USA
bDuke University Medical Center, Durham, NC 27710, USA
cSleep Disorders and Research Center, Henry Ford Hospital, Detroit, MI 48202, USA
dSleep Research Group, Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
Corresponding author. Address: Stanford Sleep Epidemiology Research Center, Stanford University School of Medicine, 3430 W. Bayshore Road, Palo Alto, CA 94303, USA. Tel.: +1 650 494 1137; fax: +1 650 493 1225.
ABSTRACT