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1 April 1995 | Volume 122 Issue 7 | Pages 493-501
Objective: To investigate the various clinical presentations of sleep-disordered breathing in women.
Design: A retrospective case–control study.
Setting: A sleep disorders clinic.
Patients: 334 women, aged 18 years and older, seen between 1988 and 1993, who were diagnosed with upper airway sleep-disordered breathing. Controls were 60 women with insomnia and 100 men with sleep-disordered breathing.
Measurements: Clinical, anatomic, and polygraphic information.
Results: The mean lag time (±SD) in women between the appearance of symptoms and a positive diagnosis was 9.7 ±3.1 years; among participants 30 to 60 years of age, the duration of untreated symptoms differed (P <0.001) between women and men. Sleep-disordered breathing was blamed for divorce or social isolation by 40% of the case patients. Abnormal maxillomandibular features were noted in 45% of the women with disordered breathing. Dysmenorrhea and amenorrhea (which disappeared after treatment with nasal continuous positive airway pressure) were reported in 43% of premenopausal women compared with 13% of persons in the control group of women with insomnia. Thirty-eight women (11.4%) with upper airway sleep-disordered breathing had a respiratory disturbance index of less than 5 and were significantly younger, had a smaller neck circumference, and had a lower body mass index than women with a respiratory disturbance index of 5 or more.
Conclusion: Physicians should revise their understanding of upper airway sleep-disordered breathing so that they notice women with certain craniofacial features, a low body mass index, a small neck circumference, and a respiratory disturbance index of less than 5. These revisions may enable more rapid diagnosis and treatment of women with sleep-disordered breathing.
All women 18 years of age and older who contacted the clinic between 1988 and 1993 with symptoms of daytime tiredness, daytime fatigue, or daytime sleepiness were identified using our computerized clinic database.
Inclusion Criteria
For study inclusion, participants must have had a complete sleep-wake evaluation and a complete report in their chart that included the results of polygraphic evaluation. All participants included in our study had daytime sleepiness, based on either a score of 9 or more on the Epworth sleepiness scale [6, 7] or a score of 8 minutes or less on the multiple sleep latency test [8]. Nocturnal recordings included an electroencephalogram, an electrooculogram, a chin and a leg electromyogram (one lead), measurements of body position, and monitoring of respiration.
Breathing patterns during sleep had to have indicated the presence of partial or complete upper airway obstruction. Initially, we looked for obstructive patterns that lasted 10 seconds and for a respiratory disturbance index (the number of apneas and hypopneas per hour of sleep) of 5 or more. In 1991, however, it was shown that clinical consequences could be seen with a respiratory disturbance index of less than 5, even in the absence of classically defined hypopneas. In this group of affected participants (with a respiratory disturbance index < 5), flow remains more or less constant, but breathing effort (as reflected by esophageal pressure) is substantially increased, leading to ARTICLE
Upper Airway Sleep-Disordered Breathing in Women
Most surveys of the obstructive sleep apnea syndrome have emphasized the predominance of the syndrome in men, and the few reports [1-3] describing adult women with this syndrome have emphasized its frequent association with massive obesity. Previous reports have suggested that the appearance of the obstructive sleep apnea syndrome is 10 to 20 times more common in men than in women. Recently, however, a survey of the general population aged 30 to 60 years by Young and colleagues [4] concluded that sleep-disordered breathing or obstructive sleep apnea associated with excessive daytime sleepiness has a prevalence of 4% in middle-aged men and of 2% in middle-aged women; Gislason and colleagues [5] estimated the prevalence at 2.5% for women in Iceland aged 40 to 59 years. The discrepancy between previous estimates of the prevalence of sleep-disordered breathing in women and these recent reports suggests that sleep-disordered breathing in women is underdiagnosed. We studied the clinical presentation and consequences of sleep-disordered breathing in a large sample of women seen during the past 4 years at the Stanford Sleep Disorders Clinic for symptoms of excessive daytime sleepiness.
Methods
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Methods
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Discussion
Author & Article Info
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Participants
arousals on the electroencephalograms (the upper airway resistance syndrome) [9]. From this point on, we included participants with obstructive patterns of a shorter duration (one to two obstructed breaths) that induced sleep disturbances and daytime symptoms but who had a respiratory disturbance index of less than 5. The abnormal breathing patterns may have been shown by different means, from the use of complex protocols involving a facemask and pneumotachometer to simpler protocols that used measurements of esophageal pressure (Pes) with inductive respiratory plethysmography, monitoring of airflow, pulse oximetry, microphone monitoring, and intercostal electromyography (Figure 1). The minimum accepted protocol for inclusion involved monitoring of airflow, inductive plethysmography, and pulse oximetry, with the addition of Pes measurements after 1991. Finally, participants had to have shown clinical improvement in response to treatment using nasal continuous positive airway pressure (or nasal bilevel positive airway pressure in obese participants with a body mass index > 36.0 kg/m2).
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Exclusion Criteria
After reviewing their chart and test results, we excluded patients with sleepiness, a history of cataplexy, and two or more periods of sleep onset with rapid eye movement on the multiple sleep latency test. These patients were diagnosed as having narcolepsy. Patients with sleepiness and specific organic disorders (repetitive nocturnal epileptic seizures, brain tumor, neuromuscular disorders, untreated hypothyroidism) were also excluded. Patients with sleepiness and specific congenital or genetic defects or both (for example, trisomy 21 and substantial craniomandibular abnormalities such as the Hurler, the Hunter, the Traecher-Collin, and the Pierre Robin syndromes and other neurocrestopathies) were excluded even if their daytime sleepiness was related to an upper airway problem during sleep. Patients with major, noncongenital craniofacial deformities (particularly those associated with mandibular involvement) were also excluded, as were patients with psychiatric mood disorders in whom daytime somnolence was clearly a symptom of depression. All other participants 18 years and older were considered for the study and had polygraphic investigation.
Selection of Controls
Women with Insomnia
We selected 60 women with insomnia, aged 18 years or older, who were seen during the same period as the index cases to serve as a control group. Use of this group as a control allowed us to compare the severity of the symptoms of these two groups of women with different sleep disorders. The control participants reported insomnia of at least 6 months duration; all were diagnosed with psychophysiologic insomnia on the basis of interviews, questionnaires, sleep logs, actigraphy, and nocturnal polygraphic recordings [10]. The control group was subdivided into six age groups (18 to 30 years, 31 to 40 years, 41 to 50 years, 51 to 60 years, 61 to 70 years, and > 70 years). Ten women were in each age group. Women with insomnia were examined successively in order of first clinic visit. When a woman met the criteria for any group, she was selected as an appropriate control for the breathing disorders group.
The upper limit of normal weight for women in the control and index groups was defined as 26.8 kg/m2 [11]. A participant was considered overweight if her body mass index was more than 27.0 kg/m2 [11]. Participants in the control and sleep-disordered breathing groups were matched for weight on the basis of the above classifications and for menopausal status. Exact matching for obesity was difficult. Our two most obese controls with insomnia had body mass indices of 35.0 kg/m2 and 32.5 kg/m2,respectively, whereas our heaviest case patient with sleep-disordered breathing had a body mass index of 59.0 kg/m2.
Men with Insomnia
We selected 100 men who had been diagnosed during the past 3 years with upper airway sleep-disordered breathing as a second control group. Controls in this group met the same inclusion and exclusion criteria as female participants. Male controls were matched with case patients for body mass index (±2 kg/m2) and respiratory disturbance index (<5 or 
5). Exact matching for obesity was easy; we were able to match the men with the women's index group for highest body mass index.
Geographic Distribution of Participants
The Stanford Sleep Disorders Clinic has a high visibility locally and nationally and has frequent exposure in the media. Forty percent of the patients seen at the clinic are self-referred. These patients come to the Clinic for various reasons: Some have already seen sleep specialists and want second opinions, some are seeking different treatment options, and some have used the telephone book and come because our location is convenient. Twenty-five percent of our patients are referred by surgeons after consultation for a snoring problem; 35% are referred by general practitioners, internists, and pulmonary physicians who may be part of a health maintenance organization or a preferred provider organization that includes Stanford Medical Center as part of its referral list.
Collected Variables and Analysis
Data on the three groups of participants were collected from interviews. We used the Sleep Questionnaire and Assessment of Wakefulness, a previously validated questionnaire covering sleep-wake symptoms, past and present sleep-wake history, medical history, and drug intake [12, 13]. The sleep specialist reviewed answers to the questionnaire at the time of the patient's interview. Demographic, familial, and social histories are also included in this sleep questionnaire and in the clinic administrative questionnaire, and these data were used in our analysis. Body mass index [14], neck circumference [15-18], and fatty distribution [19] were taken from records of the initial evaluation (done within 1 month of polysomnography). Upper airway anatomy was examined, and a diagram of anatomic abnormalities of the region was made on a standard form. In women, hormonal status was derived from their histories, and, if necessary, a follicle-stimulating hormone test was done after determining whether the women were receiving hormonal treatment (including birth control pills or estrogen as prophylaxis for osteoporosis). Daytime sleepiness indices and sleep variables for statistical analysis before and after treatment were collected from the monitored nights.
Data and Statistical Analyses
All participants were given a number, and their data were processed anonymously. Histograms were generated to describe the overall group of participants. Simple, descriptive statistics were generated using the Statview statistical computer package (Abacus Concepts, Inc., Berkeley, California). Correlation matrices were obtained. We did linear and multiple regression analyses to evaluate the effect of independently collected variables on dependent variables, such as respiratory disturbance index. Analysis of variance (ANOVA) was used for analyses of noncontinuous variables, and ANOVAs were also used, in conjunction with nonparametric statistics, to compare data obtained from the groups with sleep-disordered breathing and insomnia.
Results
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Of 334 women with sleep-disordered breathing, 161 (48.2%) were premenopausal, 86 (25.8%) were menopausal, and 87 (26%) were postmenopausal. Twenty-eight women (8.4% of the total group) were 30 years of age or younger, 35 women (10.5%) were 70 years of age or older, and 271 women (81.1%) were between 31 and 65 years of age. The mean age of the women is shown in Table 1.
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Body Mass
The median body mass index for women in the sleep-disordered breathing group was 24.1 kg/m2. Most of the case patients were not overweight [11]. Histograms generated for menopausal status (that is, premenopausal, menopausal, or postmenopausal), showed that premenopausal (younger) women weighed less than menopausal and postmenopausal women (median, 22.6 kg/m2 compared with 26.3 and 23.0 kg/m2, respectively; ANOVA, P < 0.03).
Sleep-Disordered Breathing
Table 2 shows the relation between respiratory disturbance index and several other variables. Women with a low respiratory disturbance index were younger than the other participants. In participants with a respiratory disturbance index of less than 5 (the upper airway resistance syndrome) [9], neck circumference was not a useful differential variable. Women with a respiratory disturbance index of more than 15 events (apneas and hypopneas) per hour had larger neck circumferences [18], whereas those with a respiratory disturbance index of more than 30 had greater body mass indices (P < 0.01). The highest respiratory disturbance indices were seen in the most obese women with the largest neck circumferences.
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Linear regression analysis was done with respiratory disturbance index as the dependent variable and with age and body mass index as independent variables; the analysis indicated that body mass index correlated with the respiratory disturbance index (F = 98.6; P < 0.0001). We found a positive relation between menopausal status (menopausal and postmenopausal) and respiratory disturbance index (ANOVA, P < 0.0001). If body mass index was integrated into the model, however, menopausal status was no longer statistically related to the respiratory disturbance index.
In women with sleep-disordered breathing, a positive correlation was found (P < 0.0001) between respiratory disturbance index and minimum nocturnal oxygen saturation, and a negative correlation (P < 0.0001) was found between total sleep time and amount of time awake after sleep onset. Body mass index correlated with lowest percent of arterial oxygen saturation (SaO2) during sleep (r = 0.72). When body mass index was replaced by neck circumference in the model, the correlation coefficient was 0.58 (that is, still significant). This is not surprising because the respiratory disturbance index depends primarily on abnormalities in the upper airway, but the lowest SaO2 also depends on abdominal obesity, particularly during rapid eye movement sleep and rapid eye movement sleep-related atonia.
Nature of Symptoms
Tiredness, fatigue, and sleepiness may be considered similar or different by any given person. For this reason, persons with scores on the Epworth sleepiness scale or on the multiple sleep latency test suggestive of excessive daytime sleepiness often describe their symptoms in different ways. The presenting symptom was described as tiredness or fatigue by 83% of the index cases and as sleepiness by only 13% of the index case group. In response to the questionnaire, however, 87% admitted they had had symptoms of sleepiness for a long time. The remaining 13%, despite having scores of 9 or more on the Epworth sleepiness scale or scores of 8 minutes or less on the multiple sleep latency test, did not list daytime sleepiness on their questionnaire as a predominant problem; they instead listed daytime tiredness or fatigue.
Duration of Symptoms
Before referral to a physician for a sleep-related disorder, the mean duration of symptoms of excessive daytime sleepiness or of other symptoms related to sleep-disordered breathing (±SD) was 9.7 ±3.1 years. The greatest duration was 22 years. The mean duration of symptoms related to upper airway sleep-disordered breathing before appropriate referral and diagnosis is shown in (Figure 2). The data are shown by age and body mass index. The sleep-related breathing problem was recognized more quickly in elderly women than in middle-aged women and more quickly in obese women than in nonobese women.
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No statistical differences were noted between men and women younger than 30 years of age or for those 60 years of age and older. Sleep disturbances among those who were 30 to 60 years of age were recognized more slowly in women than in men (31 to 40 years, P < 0.0001; 41 to 50 years, P < 0.001; 51 to 60 years, P < 0.001). No statistical difference was noted in duration of symptoms between men and women with body mass indices of 31.0 kg/m2 or more, and the significance was borderline in those with body mass indices between 29.0 and 31.0 kg/m2 (P = 0.054). The number of men with body mass indices between 18.0 and 20.0 kg/m2 was too small (n = 3) to do valid statistical comparisons.
Symptom Analyses
Results of the symptom analysis are shown in Table 3. The group with morning headaches or heaviness reported disappearance of symptoms within 30 to 60 minutes after waking. Borderline (that is, diastolic pressure between 90 and 100 mm Hg) or high blood pressure was documented in 130 participants (38%).
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Two symptoms were of particular interest because they differed statistically from those in the control groups. First, 43% of women in the premenopausal group (n = 69) reported menstrual irregularities, including amenorrhea or long or irregular menstrual cycles (or both). Evaluation of hormonal status in these women (using questionnaires and follicle-stimulating hormone tests) confirmed their premenopausal condition. Second, 139 women (40.5%) with sleep-disordered breathing attributed divorce or dissolution of a love relationship to their chronic sleepiness and fatigue and attributed their social isolation to a physical and not a psychiatric (depressive or otherwise) problem.
In comparison, only eight women (13.3%) in the control group with chronic insomnia had menstrual irregularities, and only five women (8.3%) in the insomnia group attributed divorce or social isolation to their sleep-related problem. Although 18% of the men ended their nights with their bed partner sleeping in a different room to escape the snoring, divorce or dissolution of a relationship was attributed to sleep-disordered breathing by only 6% of this control group.
A significant association was noted between a higher respiratory disturbance index and the presence of morning headaches and between a higher body mass index and abnormal or borderline blood pressure. No significant associations were noted, however, between menstrual irregularities and severity of the respiratory disturbance index, the body mass index, or the neck circumference: Menstrual irregularities were seen in women of normal weight and in sleepy women with the upper airway resistance syndrome (that is, a respiratory disturbance index < 5).
Clinical Evaluation of the Oropharyngeal Region
The presence of higher-than-expected, narrow ogival hard palates in 46.7% of the index cases (n = 156) was noted during clinical evaluation. This anatomic pattern was associated with a triangular chin and a variable overjet (Figure 3). A class II malocclusion was noted in 141 of these 156 case patients. These anatomic features were more common among the participants who also had a low respiratory disturbance index; 76.2% (n = 131) of the women with a respiratory disturbance index of less than 15 and 76.3% (n = 29) with a respiratory disturbance index of less than 5 had these features. Twenty-five women without this anatomic feature had variable respiratory disturbance indices and marked obesity, defined as a body mass index of 35 kg/m2 or more. The rest of the case patients presented with various combinations of abnormal anatomic features and with increased body mass index.
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Effect of Nasal Continuous Positive Airway Pressure
Treatment with nasal continuous positive airway pressure for 1 to 3 months led to improvement in daytime sleepiness in all case patients, as measured by multiple sleep latency test scores or by Epworth sleepiness scale scores (P < 0.001). Residual problems were noted, but many symptoms were reported to have improved greatly, including dysmenorrhea in the premenopausal group.
Women with a Respiratory Disturbance Index of Less than 5 and Women with an Index of 5 or More
Patients with clinical symptoms and a respiratory disturbance index of less than 5 have been poorly documented in previous reports. Thus, we compared this group to the better-described group with a respiratory disturbance index of 5 or more. In women with a respiratory disturbance index of less than 5, the median age was 38 years (range, 22 to 79 years), the median body mass index was 22.5 kg/m2 (range, 18.6 to 57 kg/m2; only three patients had a body mass index > 26.1 kg/m2), and the median neck circumference was 32.8 cm (range, 32 to 38 cm) Figure 3 and Table 4. Twenty-three of the women with a respiratory disturbance index of less than 5 (57% of the subgroup) were loud, regular snorers, but 8 case patients (20%) were not snorers. When compared with all of the participants, women with a respiratory disturbance index of less than 5 had smaller neck circumferences (P < 0.05) and were younger (P < 0.01). Seventy-five percent of these women were premenopausal compared with 48.2% of the total group.
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Women with a Respiratory Disturbance Index of Less than 5 and No Substantial Sleep Fragmentation
Eleven women (27.5% of the subgroup with a respiratory disturbance index of less than 5) behaved differently. These 11 women, despite their reported sleepiness confirmed by a mean score of 7.7 ±1.1 minutes on the multiple sleep latency test, had a small amount of time awake after sleep onset and an absence of transient arousals (no activity) on their electroencephalograms (that is, they had no evidence of sleep fragmentation as was seen in the other patients with a respiratory disturbance index < 5). They had a mean total sleep time of 476.5 minutes, a mean time awake after sleep onset of only 24.6 minutes, and a mean number of transient electroencephalographic arousals ( activity) of 6 per hour of sleep. The mean age of these 11 women was 35.3 years, and only 1 woman was in the menopausal-postmenopausal group.
This subgroup of 11 women included the heaviest woman, who had a body mass index of 57.3 kg/m2 but a neck circumference of only 38 cm [18]. This subgroup had a mean body mass index of 24.95 kg/m2, but if we eliminated the most obese case patient, the other 10 women had a mean body mass index of 19.2 kg/m2. Overall, they were slim but had very high, arched palates, a mean overjet of 9 ±1.5 mm, and small triangular chins.
Comparison of Men and Women with Respiratory Disturbance Indices of Less than 5
Results for these comparisons are shown in Table 4. In men with a respiratory disturbance index of less than 5, trends were noted toward younger age and larger neck circumference (P < 0.06) when compared with the total group of men. One man had been diagnosed with the chronic fatigue syndrome, but most (72%) of the men with a respiratory disturbance index of less than 5 had been previously diagnosed as having idiopathic hypersomnia (seven men) or narcolepsy (one man).
Interestingly, 20 women in the group with a respiratory disturbance index of less than 5 (53%) had been previously diagnosed and, in some manner, treated for the chronic fatigue syndrome. Thus, men had been symptomatically treated, whereas women had not.
Discussion
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Many of the women in our study, particularly those with the upper airway resistance syndrome, were not obese and did not have large necks. Instead, their most telling clinical feature was the presence of certain craniofacial anomalies. Several investigators, including ourselves [20, 21], have previously noted the association between mild craniofacial anomalies and sleep-disordered breathing. Our report confirms that greater attention should be paid to clinical evaluation of maxillofacial-palatopharyngeal anatomic features.
Women who do not fit the conventional clinical picture of sleep-disordered breathing wait years before being appropriately diagnosed. Several factors may account for this delay. First, the association between certain physical symptoms (such as dysmenorrhea or amenorrhea) and upper airway sleep-disordered breathing has been missed. Even symptoms of tiredness and fatigue have not always been equated with pathologic sleepiness by physicians, as shown by the substantial number of women, particularly those with a respiratory disturbance index of less than 5, who had been diagnosed with the chronic fatigue syndrome. In patients who had symptoms of sleepiness but had a low respiratory disturbance index, specialists may have been misled by the absence of sleep apnea or sleep hypopnea as classically defined. Further, the international criteria [10] often used to score arousals are misleading because they do not include the transient electroencephalographic arousals ( activity) that are responsible for sleep fragmentation in persons with upper airway sleep-disordered breathing [9]. Indeed, it was only through the systematic monitoring of esophageal pressure (an indicator of respiratory effort) and a more sophisticated protocol that we were able to show the relation between abnormal upper airway resistance and repetitive, transient electroencephalographic arousals ( activity) [9, 22].
Previously, we showed that excessive somnolence (confirmed by a multiple sleep latency test) can be induced in a healthy, young person by replicating (with auditory stimuli) the transient electroencephalographic arousals ( activity) that are characteristic of the upper airway resistance syndrome [23]. Using visual scoring, however, we were unable to show the presence of a high number of transient electroencephalographic arousals ( activity) in 11 case patients with a respiratory disturbance index of less than 5. The number of transient electroencephalographic arousals per hour of sleep in these case patients was low and, in fact, did not differ from that seen in the control group of persons with insomnia or even from the published data on normal controls. Various hypotheses may account for this result.
1. Variability occurs from night to night in the number of transient arousals, and we may have done recordings on nights in which the frequency of arousals was low. Evidence against this interpretation is the fact that in all 11 case patients, recordings were done for more than one night.
2. A different response to sleep fragmentation may occur; certain participants may be more sensitive than others (that is, may have a lower threshold to daytime sleepiness).
3. Increased respiratory effort, clearly shown during the monitoring, exacts a metabolic cost despite the absence of transient electroencephalographic arousals.
4. Visual scoring of transient electroencephalographic arousals is sometimes inadequate because it is based on pattern recognition that requires complicated eye adaptation. The minimum duration of encephalographic change necessary to recognize an encephalographic arousal varies depending on the encephalographic background, and our analysis may have missed some electroencephalographic changes.
We favor this last interpretation, even though the last three hypotheses may all be correct. Although our team is experienced in sleep recording and great attention was paid to appropriate scoring of these short electroencephalographic events, we must emphasize the difficulty of visually scoring transient electroencephalographic arousals. Investigation using computer analysis may show that our 11 women also have disturbed sleep, as measured by the electroencephalograms, with corresponding overall sleep fragmentation that is not easily recognizable by visual scoring.
One hypothesis is that the hormonal status of premenopausal women may protect them from developing the obstructive sleep apnea syndrome; thus, menopause may enhance the risk for developing the disorder [24]. Our data indicate that the severity of the apnea-hypopnea index increases with onset of menopause but obesity also increases with onset of menopause. The effect of menopause on the upper airway resistance syndrome and on the severity of the obstructive sleep apnea syndrome remains an unresolved issue.
Finally, persons with sleep-disordered breathing have reduced quality of life. Our study indicates that abnormal breathing during sleep may have a substantial effect on women's personal relationships. Interestingly, although men may have sought consultation because of the familial disturbance created by their snoring and the exodus of the bed partner from the bedroom during the night, this exodus did not lead to divorce and complete dissolution of the relationship, as it often did with women.
Data collected by Young and colleagues [4] indicate that 2% of women aged 30 to 60 years have the obstructive sleep apnea syndrome. This calculation is based on participants with a respiratory disturbance index of 5 or more and with symptoms of daytime somnolence. Our study shows that disordered breathing during sleep in persons with a respiratory disturbance index of less than 5 is also associated with a clinical symptom of sleepiness treatable by nasal continuous positive airway pressure and suggests that a prevalence of 2% may be a low estimate of the problem [4]. Considering the overall effect of sleep-disordered breathing on women, it is crucial to create an accurate clinical picture of the syndrome to help physicians recognize a problem that typically goes unrecognized in women for many years.
Author and Article Information
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References
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1. Rajala R, Partinen M, Sane T, Pelkonen R, Huikuri K, Seppalainen MA. Obstructive sleep apnea syndrome in morbidly obese patients. J Intern Med. 1991; 230:125-9.
2. Wilhoit SC, Suratt PM. Obstructive sleep apnea in premenopausal women. A comparison with men and with postmenopausal women. Chest. 1987; 91:654-8.
3. Guilleminault C, Quera-Salva MA, Partinen M, Jamieson A. Women and the obstructive sleep apnea syndrome. Chest. 1988; 93:104-9.
4. Young T, Palta M, Dempsey J, Skatrud J, Weber S, Badr S. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med. 1993; 328:1230-5.
5. Gislason T, Benediktsdottir B, Bjornsson JK, Kjartansson G, Kjeld M, Kristbjarnarson H. Snoring, hypertension, and the sleep apnea syndrome. An epidemiologic survey of middle-aged women. Chest. 1993; 103:1147-51.
6. Johns MW. A new method for measuring daytime sleepiness, the Epworth sleepiness scale. Sleep. 1991; 14:540-5.
7. Johns MW. Reliability and factor analysis of the Epworth Sleepiness Scale. Sleep. 1992; 15:376-81.
8. Carskadon MA, Dement WC, Mitler MM, Roth T, Westbrook PR, Keenan S. Guidelines for the multiple sleep latency test (MSLT): a standard measure of sleepiness. Sleep. 1986; 9:519-24.
9. Guilleminault C, Stoohs R, Clerk A, Cetel M, Maistros P. A cause of excessive daytime sleepiness. The upper-airway resistance syndrome. Chest. 1993; 104:781-7.
10. Rechtschaffen A, Kales A, eds. A Manual of Standardized Terminology, Techniques and a Scoring System for Sleep Stages of Human Subjects. Los Angeles Brain Information Service-Brain Research Institute; University of California at Los Angeles; 1968; National Institutes of Health publication no. 204/G.
11. National Center for Health Statistics. Health United States 1985. Hyattsville, Maryland: U.S. Department of Health and Human Services; 1985.
12. Douglass AB, Bornstein R, Nino-Murcia G, Keenan S, Milers L, Zarcone VP, et al. Item test-retest reliability of the sleep disorders questionnaire. Sleep Research. 1990; 19:215.
13. Douglass AB, Bornstein R, Nino-Murcia G, Keenan S, Milers L, Zarcone VP, et al. Creation of the ASDC Sleep Disorders Questionnaire. Sleep Research. 1986; 15:117.
14. Kohosla T, Lowe CR. Indices of obesity derived from body weight and height. Br J Prev Soc Med. 1967; 21:122-8.
15. Davies RJ, Ali NJ, Stradling JR. Neck circumference and other clinical features in the diagnosis of the obstructive sleep apnoea syndrome. Thorax. 1992; 47:101-5.
16. Hoffstein V, Mateika S. Differences in abdominal and neck circumferences in patients with and without obstructive sleep apnoea. Eur Respir J. 1992; 5:377-81.
17. Katz I, Stradling J, Slutsky AS, Zamel N, Hoffstein V. Do patients with sleep apnea have thick necks? Am Rev Respir Dis. 1990; 141:1228-31.
18. Young T, Palta M, Badr MS. Sleep-disordered breathing (Letter). N Engl J of Med. 1993; 329:1429-30.
19. Peiris AN, Sothmann MS, Hoffman RG, Hennes MI, Wilson CR, Gustafson AB, et al. Adiposity, fat distribution, and cardiovascular risks. Ann Intern Med. 1989; 110:867-72.
20. Jamieson A, Guilleminault C, Partinen M, Quera-Salva MA. Obstructive sleep apneic patients have craniomandibular abnormalities. Sleep. 1986; 9:469-77.
21. Partinen M, Guilleminault C, Quera-Salva MA, Jamieson A. Obstructive sleep apnea and cephalometric roentgenograms. The role of anatomic abnormalities in the definition of abnormal breathing during sleep. Chest. 1988; 93:1199-205.
22. Flemale A, Gillard C, Dierckx JP. Comparison of central venous, esophageal and mouth occlusion, pressures with water-filled catheters for estimating pleural pressure changes in healthy adults. Eur Respir J. 1988; 1:51-7.
23. Philip P, Stoohs R, Guilleminault C. Sleep fragmentation in normals: a model of upper airway resistance syndrome. Sleep. 1994; 17:242-7.
24. Pickett CK, Regensteiner JG, Woodward WD, Hagerman DD, Weil JV, Moore LG. Progestin and estrogen reduce sleep-disordered breathing in postmenopausal women. J Appl Physiol. 1989; 66:1656-61.
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|
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C. Guilleminault and R. Dave Upper Airway Resistance Syndrome, Insomnia, and Functional Somatic Syndromes Chest, January 1, 2003; 123(1): 12 - 14. [Full Text] [PDF]
|
|
|
|
|
|
R. A. Dart, J. R. Gregoire, D. D. Gutterman, and S. H. Woolf The Association of Hypertension and Secondary Cardiovascular Disease With Sleep-Disordered Breathing Chest, January 1, 2003; 123(1): 244 - 260. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. E. Peppard, T. Young, M. Palta, J. Dempsey, and J. Skatrud Longitudinal Study of Moderate Weight Change and Sleep-Disordered Breathing JAMA, December 20, 2000; 284(23): 3015 - 3021. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E. BLACK, C. GUILLEMINAULT, I. M. COLRAIN, and O. CARRILLO Upper Airway Resistance Syndrome . Central Electroencephalographic Power and Changes in Breathing Effort Am. J. Respir. Crit. Care Med., August 1, 2000; 162(2): 406 - 411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. J. Douglas Upper Airway Resistance Syndrome Is Not a Distinct Syndrome Am. J. Respir. Crit. Care Med., May 1, 2000; 161(5): 1413 - 1415. [Full Text]
|
|
|
|
|
|
C. O'CONNOR, K. S. THORNLEY, and P. J. HANLY Gender Differences in the Polysomnographic Features of Obstructive Sleep Apnea Am. J. Respir. Crit. Care Med., May 1, 2000; 161(5): 1465 - 1472. [Abstract] [Full Text]
|
|
|
|
|
|
REBUTTAL FROM DR. DOUGLAS Am. J. Respir. Crit. Care Med., May 1, 2000; 161(5): 1415b - 1416. [Full Text]
|
|
|
|
 |
|
 Y. Finkelstein, D. Wexler, G. Berger, A. Nachmany, M. Shapiro-Feinberg, and D. Ophir Anatomical Basis of Sleep-Related Breathing Abnormalities in Children With Nasal Obstruction Arch Otolaryngol Head Neck Surg, May 1, 2000; 126(5): 593 - 600. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. C. Fletcher, J. Stich, and K. L. Yang Unattended Home Diagnosis and Treatment of Obstructive Sleep Apnea Without Polysomnography Arch Fam Med, February 1, 2000; 9(2): 168 - 174. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J SCHWAB Sex differences and sleep apnoea Thorax, April 1, 1999; 54(4): 284 - 285. [Full Text]
|
|
|
|
|
|
R. D. CHERVIN and M. S. ALDRICH Effects of Esophageal Pressure Monitoring on Sleep Architecture Am. J. Respir. Crit. Care Med., September 1, 1997; 156(3): 881 - 885. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. M. Claman and B. A. Votteri EFFECTS OF ESOPHAGEAL PRESSURE MONITORING ON SLEEP ARCHITECTURE Am. J. Respir. Crit. Care Med., May 1, 1997; 157(5): 1697 - 1698. [Full Text]
|
|
|
|
 |
|
 Sleep Apnea Profiled in Women Journal Watch Psychiatry, June 1, 1995; 1995(601): 17 - 17. [Full Text]
|
|
|
|
 |
|
 SLEEP APNEA IN WOMEN Journal Watch (General), April 14, 1995; 1995(414): 5 - 5. [Full Text]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||
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