@article {623,
	title = {Does snoring predict sleepiness independently of apnea and hypopnea frequency?},
	journal = {Am J Respir Crit Care Med},
	volume = {162},
	year = {2000},
	month = {2000 Oct},
	pages = {1512-7},
	abstract = {<p>Obstructive apneas and hypopneas during sleep are a well recognized cause of excessive daytime sleepiness. Snoring is also associated with excess sleepiness, although it is not known whether this reflects an independent effect of snoring or whether snoring is simply a marker for obstructive sleep apnea. To further explore the relation of snoring to sleepiness, we conducted a cross-sectional cohort study of community-dwelling adults participating in the Sleep Heart Health Study. The study sample comprises 2,737 men and 3,040 women with a mean age of 64 (SD 11) yr. Sleepiness was quantified using the Epworth Sleepiness Scale (ESS). Snoring history was obtained via a self-completion questionnaire. The respiratory disturbance index (RDI), defined as the number of apneas plus hypopneas per hour of sleep, was measured during in-home polysomnography. The ESS score increased progressively with increasing RDI, from a mean of 7.1 (4.2) in subjects with RDI < 1.5 to 8.8 (4.8) in subjects with RDI >/= 15 (p < 0.001). A progressive increase in ESS score was also seen across five categories of snoring frequency, from 6.4 (4.2) in current nonsnorers to 9.3 (4.8) in subjects who snored six to seven nights per week (p < 0.001). The prevalence of excessive daytime sleepiness, defined as an ESS score >/= 11, increased from 15\% in never-snorers to 39\% in those who snored six to seven nights per week. The relation of snoring to sleepiness was seen at all levels of RDI, with no significant change in the relation of snoring to ESS score after adjustment for RDI in multivariate models. The effects of snoring and RDI on sleepiness were little affected by adjustment for age, sex, race, body mass index, or questionnaire evidence of insufficient sleep time or nocturnal leg jerks or cramps. We conclude that both snoring and RDI are independently associated with excess sleepiness in community-dwelling, middle-aged and older adults.</p>},
	keywords = {Adult, Aged, Arousal, Cohort Studies, Cross-Sectional Studies, Female, Humans, Male, Middle Aged, Polysomnography, Risk Factors, Sleep Apnea, Obstructive, Snoring, Wakefulness},
	issn = {1073-449X},
	doi = {10.1164/ajrccm.162.4.9911073},
	author = {Gottlieb, D J and Yao, Q and Redline, S and Ali, T and Mahowald, M W}
}
@article {609,
	title = {Effects of varying approaches for identifying respiratory disturbances on sleep apnea assessment.},
	journal = {Am J Respir Crit Care Med},
	volume = {161},
	year = {2000},
	month = {2000 Feb},
	pages = {369-74},
	abstract = {<p>Varying approaches to measuring the respiratory disturbance index (RDI) may lead to discrepant estimates of the severity of sleep-disordered breathing (SDB). In this study, we assessed the impact of varying the use of corroborative data (presence and degree of desaturation and/or arousal) to identify hypopneas and apneas. The relationships among 10 RDIs defined by various definitions of apneas and hypopneas were assessed in 5,046 participants in the Sleep Heart Health Study (SHHS) who underwent overnight unattended 12-channel polysomnography (PSG). The magnitude of the median RDI varied 10-fold (i.e., 29.3 when the RDI was based on events identified on the basis of flow or volume amplitude criteria alone to 2.0 for an RDI that required an associated 5\% desaturation with events). The correlation between RDIs based on different definitions ranged from 0.99 to 0.68. The highest correlations were among RDIs that required apneas and hypopneas to be associated with some level of desaturation. Lower correlations were observed between RDIs that required desaturation as compared with RDIs defined on the basis of amplitude criteria alone or associated arousal. These data suggest that different approaches for measuring the RDI may contribute to substantial variability in identification and classification of the disorder.</p>},
	keywords = {Adult, Aged, Aged, 80 and over, Arousal, Diagnosis, Differential, Female, Humans, Lung Volume Measurements, Male, Middle Aged, Observer Variation, Oxygen, Oxyhemoglobins, Polysomnography, Risk Factors, Sleep Apnea Syndromes},
	issn = {1073-449X},
	doi = {10.1164/ajrccm.161.2.9904031},
	author = {Redline, S and Kapur, V K and Sanders, M H and Quan, S F and Gottlieb, D J and Rapoport, D M and Bonekat, W H and Smith, P L and Kiley, J P and Iber, C}
}
