Effect of obesity and erect/supine posture on lateral cephalometry: relationship to sleep-disordered breathing.

Craniofacial and upper airway anatomy, obesity and posture may all play a role in compromising upper airway patency in patients with the sleep apnoea/hypopnoea syndrome. The aim of this study was to investigate the relationship between obesity, facial structure and severity of sleep-disordered breathing using lateral cephalometric measurements and to assess the effect of body posture on cephalometric measurements of upper airway calibre variables in obese and non-obese subjects. Lateral cephalometry was carried out in erect and supine postures in 73 awake male subjects randomly selected from patients referred for polysomnography who had a wide range of apnoea/hypopnoea frequencies (1-131 events x h sleep(-1)). Subjects were divided into non-obese (body mass index (BMI) < 30 kg x m(-2); n=42) and obese (BMI > or = 30 kg x m(-2); n=31) groups. Significant but weak correlations were found between apnoea/hypopnoea index (AHI) and measurements reflecting upper airway dimensions: uvular protrusion-posterior pharyngeal wall (r=-0.26, p<0.05) and hyoid-posterior pharyngeal wall (r=0.26, p<0.05). Multiple regression using both upper airway dimensions improved the correlation to AHI (r=0.34, p=0.01). Obese subjects had greater hyoid-posterior pharyngeal wall distances than non-obese subjects, both erect (42+/-5 versus 39+/-4 mm, respectively (mean+/-SD) p<0.01) and supine (43+/-5 versus 40+/-4 mm, p<0.05). Skeletal craniofacial structure was similar in obese and non-obese subjects. In conclusion, measurements reflecting upper airway size were correlated with the severity of sleep-disordered breathing. Differences in upper airway size measurements between obese and non-obese subjects were independent of bony craniofacial structure.     

Family aggregation of upper airway soft tissue structures in normal subjects and patients with sleep apnea

RATIONALE: Sleep apnea is believed to be a genetic disorder. Thus, we hypothesized that anatomic risk factors for sleep apnea would demonstrate family aggregation. OBJECTIVES: We used volumetric magnetic resonance imaging in a sib pair "quad" design to study the family aggregation of the size of upper airway soft tissue structures that are associated with increased risk for obstructive sleep apnea. METHODS: We examined 55 sleep apnea probands (apnea-hypopnea index [AHI]: 43.2 +/- 26.3 events/h), 55 proband siblings (AHI: 11.8 +/- 16.6 events/h), 55 control subjects (AHI: 2.1 +/- 1.7 events/h), and 55 control siblings (AHI: 4.2 +/- 4.0 events/h). The study design used exact matching on ethnicity and sex, frequency matching on age, and statistical control for visceral neck fat and craniofacial dimensions. MEASUREMENTS AND MAIN RESULTS: The data support our a priori hypothesis that the volume of the important upper airway soft tissue structures is heritable. The volume of the lateral pharyngeal walls (h(2) = 36.8%; p = 0.001), tongue (h(2) = 36.5%; p = 0.0001), and total soft tissue (h(2) = 37.5%; p = 0.0001) demonstrated significant levels of heritability after adjusting for sex, ethnicity, age, visceral neck fat, and craniofacial dimensions. In addition, our data indicate that heritability of the upper airway soft tissue structures is found in normal subjects and patients with apnea. Thus, it is not simply a consequence of the prevalence of apnea. CONCLUSIONS: This is the first time family aggregation of size of the upper airway soft tissue structures has been demonstrated.     

Gender differences in the expression of sleep-disordered breathing : role of upper airway dimensions.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is a common disorder that is characterized by repetitive episodes of upper airway narrowing and collapse. Obesity is a major risk factor for OSA. Compared with men, women have greater total body fat and are more obese, and yet the prevalence of OSA is much higher in men. The airway size and compliance and pharyngeal muscle tone are important determinants of upper airway patency during sleep. The discrepancy between greater frequency of obesity and lower prevalence of OSA in women has not been explained and suggests a different pathogenetic mechanism underlying this condition. Most clinical studies in OSA have either combined the sexes or have described results from men only. The object of this study was twofold: (1) to examine the effect of obesity on pharyngeal size in both men and women, and (2) to determine the role of upper airway dimensions in the expression of sleep-disordered breathing (SDB) and its relationship to gender. DESIGN: Prospective study of subjects referred for evaluation of SDB. SETTING: University-based sleep center. SUBJECTS: Seventy-eight male patients (mean +/- SE age, 49.2 +/- 1.5 years) and 52 female patients (mean age, 47.4 +/- 1.5 years). MEASUREMENTS AND RESULTS: All subjects underwent in-laboratory polysomnography with measurement of upper airway size using the acoustic reflectance method. Although the two groups were similar in age, the female patients were slightly heavier than the male patients (body mass index [BMI], 36.0 +/- 1.7 kg/m(2) vs 33.3 +/- 0.8 kg/m(2), respectively; p < 0.0001). Despite similar clinical presentation of snoring and excessive daytime sleepiness, women had mild OSA (respiratory disturbance index [RDI], 9.2 +/- 2.7 events per hour) or increased upper airway resistance syndrome compared with men with more severe OSA (RDI, 28.0 +/- 3.5 events per hour; p < 0.0001). In contrast, women had a significantly smaller oropharyngeal junction and pharynx than men (p < 0.02). Upper airway size correlated significantly with the severity of sleep apnea in men only. There was no correlation between BMI and pharyngeal size in either gender. CONCLUSIONS: This study demonstrates that the static properties of upper airway in awake men but not women correlate with the severity of sleep apnea. This suggests inherent structural and functional differences in upper airway during sleep between men and women with more favorable airway mechanics in women.     

Daytime polysomnography for early diagnosis and treatment of patients with suspected sleep-disordered breathing

Excessive daytime sleepiness (EDS) is a common complaint among patients with sleep-disordered breathing (SDB). Population-based studies on traffic and industrial accidents suggest a relationship between EDS and life-threatening events, and adults with EDS have cognitive and memory problems. Nocturnal polysomnography (nPSG) is essential for diagnosing SDB but it is time and energy consuming. We examined the usefulness of daytime polysomnography (dPSG) for the early diagnosis and treatment of patients with suspected SDB. We studied 108 consecutive patients aged 51.9 +/- 13.5 years (mean+/-SD). All patients underwent dPSG and nPSG. The number of apnea/hypopnea episodes per hour (apnea/hypopnea index: AHI) and the number of 3% desaturation episodes per hour (desaturation index: DSI) were calculated. All patients were classified into two groups. The REM group consisted of subjects who had an AHI < or = 25/h, AHI(REM)/AHI(NREM) > 2, and AHI(NREM) < 15/h. Those who did not satisfy these criteria were placed in the NREM group. Continuous positive airway pressure (CPAP) titration was performed for patients whose AHI was > or =20/h on dPSG. Using the international classification of sleep disorders, 96 patients were diagnosed as obstructive sleep apnea [including five upper airway resistance syndrome (UARS) patients], six patients were snoring, four had idiopathic hypersomnia due to a medical condition, and two had circadian rhythm sleep disorders. The sensitivity of dPSG for AHI was 81.0%, specificity was 100%, and accuracy was 83.5%. The sensitivity and accuracy of dPSG for AHI in the REM group were considerably lower than in the NREM group. There was no significant difference for optimal CPAP between dPSG and nPSG. In the five patients with UARS, their AHI, DSI, and arousal index on dPSG were 0.92 +/- 1.2/h, 2.9 +/- 3.4/h, and 29.3 +/- 3.5/h, respectively, and their AHI and DSI on nPSG were 3.2 +/- 2.5/h and 2.8 +/- 2.4/h, respectively. However, their respiratory effort-related arousals were 37.9 +/- 7.4/h, and their arousal index was 33.2 +/- 6.3/h. The five patients with UARS were also treated with CPAP, and their daytime sleepiness was improved. Although dPSG has limitations, these results indicate that dPSG recording is clinically useful for the diagnosis of and determination of types of treatment in patients with suspected SDB.     

Prevalence of sleep-disordered breathing and continuous positive airway pressure compliance: results in chinese patients with first-ever ischemic stroke

OBJECTIVE: To assess the prevalence of sleep-disordered breathing (SDB), continuous positive airway pressure (CPAP) acceptance, and CPAP compliance in patients who have experienced ischemic stroke. DESIGN: A case-controlled study. SETTING: A university hospital. MEASUREMENTS AND RESULTS: We recruited 23 women and 28 men, who were admitted to the hospital within 4 days of stroke onset, with a mean (+/- SD) age of 64.2 +/- 13.0 years and a body mass index (BMI) of 24.3 +/- 4.4 kg/m(2) for this study. Twenty-seven patients (53%) and 9 patients (17.6%), respectively, reported a history of snoring and severe daytime sleepiness prior to experiencing a stroke, while the mean Epworth sleepiness scale score was 6.8 +/- 3.6. Polysomnography revealed 34 patients (67%) with an apnea-hypopnea index (AHI) of > or = 10 events per hour, 31 patients (61%) with an AHI of > or = 15 events per hour, and 25 patients (49%) with an AHI of > or = 20 events per hour. Significant obstructive SDB, defined as an AHI of > or = 20/h, was more prevalent in ischemic stroke patients than in control subjects (49% vs 24%, respectively; p = 0.04) and was associated with a higher BMI (p = 0.046). Among the 34 patients with an AHI of > or = 10/h, CPAP titration was tolerated by 16 patients, but only 4 patients who had typical sleep apnea features proceeded to home CPAP treatment with objective compliance over a period of 3 months of 2.5 +/- 0.6 h per night. A subgroup of 20 patients not receiving CPAP showed partial spontaneous improvement of SDB at 1 month (baseline AHI, 32.3 +/- 17.6 events per hour; AHI at 1 month, 23.0 +/- 18.8 events per hour; p = 0.01) with a trend toward improvement for the obstructive but no significant change for the central events, whereas no improvement in AHI was noted for the four patients receiving CPAP. CONCLUSION: There is a high prevalence of obstructive SDB in patients who have experienced acute ischemic stroke, which, in many cases, is different from classic obstructive sleep apnea syndrome, and this is reflected by the lack of significant sleepiness, poor CPAP acceptance, and partial spontaneous improvement at 1 month.     

A community study of sleep-disordered breathing in middle-aged Chinese men in Hong Kong

BACKGROUND: Sleep-disordered breathing (SDB) in Asian populations is being increasingly recognized. This study investigated the prevalence of SDB in Chinese middle-aged office-based male workers in Hong Kong. METHODS: Sleep questionnaires were distributed to 1,542 men (age range, 30 to 60 years), and 784 questionnaires were returned. Subsequently, full polysomnographic (PSG) examinations were conducted in 153 questionnaire respondents. Subjects with an apnea-hypopnea index (AHI) > or =5 were recalled for clinical assessment. RESULTS: Questionnaire respondents were similar in age and body mass index (BMI) to the general community in the target age range and gender. Habitual snoring was reported by 23% of this cohort and was associated with excessive daytime sleepiness (EDS), hypertension, witnessed abnormal breathing pattern, BMI, and leg movements during sleep. Allowing for subject bias in undergoing PSG, the estimated prevalence of SDB and obstructive sleep apnea syndrome (OSAS) (defined as SDB in the presence of EDS) at various AHI cutoff threshold values was 8.8% and 4.1% (AHI > or =5), 6.3% and 3.2% (AHI > or =10), and 5.3% and 3.1% (AHI > or =15). Multiple stepwise logistic regression analysis identified BMI, habitual snoring, time taken to fall asleep, and age as predictors of SDB at AHI > or =5. Analysis of anthropometric parameters indicated that the relative risk of OSAS attributable to obesity was less than in white subjects. CONCLUSION: This community-based study of sleep apnea among middle-aged men in Hong Kong using full PSG demonstrated an estimated prevalence of OSAS (AHI > or =5 and EDS) at 4.1%. Increasing BMI and age were associated with SDB, although factors other than adiposity may also have an important pathogenic role in OSA in Chinese subjects.     

Gender differences in sleep apnea: the role of neck circumference

STUDY OBJECTIVES: To determine whether differences in sleep apnea severity between men and women referred to a sleep clinic are related to the differences in neck circumference (NC). STUDY DESIGN: Case series. SETTING: University hospital sleep disorders clinic. PARTICIPANTS: A total of 3,942 patients (2,753 men and 1,189 women) referred to the sleep clinic. MEASUREMENTS AND RESULTS: All patients underwent nocturnal polysomnography. NC was used as a surrogate measure of upper airway obesity. We found that sleep apnea, defined an the apnea/hypopnea index (AHI) > 10/h, was significantly more frequent (60% vs 32%, chi(2) < 0.0001) and severe (mean +/- SE, 25 +/- 26/h vs 12 +/- 19/h, p < 0.0001) in men than in women. Men had significantly larger NC than women, but the difference became much less pronounced when we normalized NC to body height (0.24 +/- 0.02 vs 0.23 +/- 0.03, p < 0.0001). Men had significantly higher AHI than women even after controlling for age, body mass index (BMI), and neck/height ratio (NHR); analysis of covariance showed that mean AHI was 24.4 +/- 0.4 in men vs 14.8 +/- 0.7 in women (p < 0.0001). This difference persisted even when we matched men and women for NHR and BMI. Finally, multiple regression analysis revealed the following: (1) NHR was the most significant predictor of AHI, accounting for 19% of the variability; and (2) the slope of AHI vs NHR was significantly higher in men than in women. CONCLUSIONS: We conclude the following: (1) the frequency and severity of sleep apnea in the sleep clinic population is greater in men than women, and (2) factors other than NC, age, and BMI must contribute to these gender differences.     

Systemic hypertension in snorers with and without sleep apnea.

To investigate the impact of sleep-disordered breathing events on daytime hypertension (HT) in patients with increased upper airway resistance during sleep, we studied 191 male snorers aged 49.9 +/- 0.8 years. In 116 of them, an apnea-hypopnea index (AHI) above 10--defined as the presence of obstructive sleep apnea (OSA)--was found; the other 75 subjects had an AHI lower than 10 and were classified as habitual snorers (HSN). Prevalence of HT was not different between OSA (56 of 116 = 48 percent) and HSN (33 of 75 = 44 percent) and there was also no difference in systolic, diastolic, and mean blood pressures between the two groups. Hypertensive OSA patients had higher body mass index (BMI) than normotensive OSA subjects (31.4 +/- 0.7 vs 29.4 +/- 0.6; p less than 0.05), but there was no difference in age, AHI, and nocturnal oxygenation parameters. The same was true for the HSN group, with hypertensive subjects being more obese than normotensive subjects (BMI: 30 +/- 0.8 vs 27.3 +/- 0.8; p less than 0.05), but no difference in age and polysomnographic features. Discriminant analysis with HT as the classification variable and age, BMI, AHI, mean, and lowest nocturnal oxyhemoglobin saturation as independent variables, revealed an independent influence on HT only for BMI (F-prob = 0.001). Thus, our results stand against the hypothesis of a causal relationship between sleep-disordered breathing events and daytime hypertension. We conclude that the high prevalence of HT in male snorers is more directly linked to obesity than to sleep apnea, but an independent effect of snoring per se cannot be excluded.     

Inflammatory mediators in exhaled breath condensate of children with obstructive sleep apnea syndrome

BACKGROUND: Upper airway inflammation is now recognized in adults with obstructive sleep apnea (OSA) syndrome. However, the role played by eicosanoids such as leukotrienes and prostaglandins is unclear. OBJECTIVE: To investigate whether eicosanoids are measurable in exhaled breath condensate (EBC), and to determine whether differences in these inflammatory mediators emerge among children with and without sleep-disordered breathing (SDB). METHODS: EBC was collected from 50 consecutive snoring children undergoing overnight polysomnography for suspected SDB, and from 12 nonsnoring control subjects. Prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and cysteinyl leukotrienes (cys-LTs: leukotriene C4 [LTC4]/leukotriene D4 [LTD4]/leukotriene E4 [LTE4]) EBC levels were analyzed using enzyme-linked immunosorbent assay. RESULTS: LTB4 levels were elevated in children with an apnea-hypopnea index (AHI) > 5/h (SDB; 97.6 +/- 6.3 pg/mL) compared to children with an AHI < 5/h (mild SDB; 66.4 +/- 19.1 pg/mL; p < 0.01) and control subjects (27.8 +/- 3.7 pg/mL; p < 0.01). Similarly, cys-LT (LTC4/LTD4/LTE4) concentrations were also increased in SDB (45.1 +/- 10.6 pg/mL in SDB vs 27.6 +/- 8.3 pg/mL in mild SDB, and 15.7 +/- 7.6 pg/mL in control subjects; p < 0.01). In contrast, PGE2 concentrations were similar among the three groups. CONCLUSIONS: Inflammatory mediators such as leukotrienes and prostaglandins can be readily quantified in EBC collected from the upper airway of children. Disease severity-dependent increases in leukotriene concentrations (LTB4 and LTC4/LTD4/LTE4) emerge among children and may serve as a noninvasive tool in the clinical assessment of these children.     

Cephalometric analysis in obese and nonobese patients with obstructive sleep apnea syndrome

STUDY OBJECTIVES: The aims of this study were to comprehensively evaluate the cephalometric features of patients with obstructive sleep apnea syndrome (OSAS), and to elucidate the relationship between cephalometric variables and severity of the apnea-hypopnea index (AHI). PATIENTS: The study population consisted of 62 male patients with OSAS, classified into 33 obese patients (body mass index [BMI] >or= 27) and 29 nonobese patients (BMI < 27), and 13 male simple snorers (AHI < 5 events per hour). METHOD: and measurements: Diagnostic polysomnography and measurements of 22 cephalometric variables were carried out for all patients and simple snorers. RESULTS: Patients with OSAS in both subgroups showed several significant cephalometric features compared with simple snorers: (1) inferiorly positioned hyoid bone, (2) enlarged soft palate, and (3) reduced upper airway width at soft palate. More extensive and severe soft-tissue enlargements including anteriorly positioned hyoid bone and a longer tongue were found in the obese patients. In the nonobese patients, the anteroposterior distances of the bony nasopharynx and oropharynx were significantly smaller than those of simple snorers and obese patients. Stepwise regression analysis showed that anterior displacement of the hyoid bone and retroposition of the mandible were the dominant overall determinants for AHI in patients with OSAS, and that narrowing of the bony oropharynx and inferior displacement of the hyoid bone were dominant determinants for AHI in nonobese patients. A significant regression model for AHI using cephalometric variables could not be obtained for the obese patients, but the BMI proved to be the most significant determinant. CONCLUSION: Characteristics of the craniofacial bony structure such as narrowing of the nasopharynx and oropharynx and enlargement of the soft tissue in the upper airway may be important risk factors for the development of OSAS in nonobese patients. In obese patients, the deposition of adipose tissue in the upper airway may aggravate the severity of OSAS.     

Age related differences in electroencephalographic and cardiac arousal at the termination of sleep apnea/hypopnea

OBJECTIVE: The purpose of the present study was to determine whether electroencephalographic (EEG) and cardiac arousal, i.e. heart rate elevation at the termination of apnea/hypopnea are related to aging. METHODS: The subjects were 13 middle-aged (40-60 years of age, 47.8+/-5.35 years) and 10 elderly (>60 years of age, 69.8+/-5.31 years) male patients with obstructive sleep apnea syndrome. We evaluated the number of apneas per an hour of sleep (apnea index: AI), the number of hypopneas per an hour of sleep (hypopnea index: HI), the summation of HI and AI (apnea/hypopnea index: AHI), sleep stage, the amount of time during which nocturnal oxygen saturation was decreased below 90% (oxygen desaturation time: ODT), and EEG and cardiac arousal at the termination of apnea/hypopnea using polysomnography with pulse oximetry. RESULTS: There was no significant difference in AHI, duration of apnea/hypopnea, and sleep stage distribution between the two groups. However, the ratio of apnea/hypopnea with EEG and cardiac arousal was significantly higher in middle-aged than in elderly patients. The ratio of HI to AHI was significantly lower in middle-aged than in elderly patients. In middle-aged patients, EEG and cardiac arousal were significantly correlated with AI, AHI, and ODT, whereas, in elderly patients, these parameters were not similarly correlated. CONCLUSION: Our findings suggest that the differences in EEG and cardiac arousal, and the pattern of sleep-disordered breathing (SDB) between middle-aged and elderly patients with SDB might be a physiological phenomenon of aging.     

Circulating plasma levels of vascular endothelial growth factor in patients with sleep disordered breathing

INTRODUCTION: Cellular vascular endothelial growth factor (VEGF) expression is increased in response to regional hypoxia, however, contradictory results were reported on the effects of systemic hypoxemia on circulating VEGF levels. This study investigated plasma concentrations of VEGF in patients with a variable degree of overnight hypoxemia due to sleep disordered breathing (SDB). METHODS: VEGF levels were assessed by ELISA in non-activated (VEGFbl) and thrombin stimulated platelet rich plasma (VEGFprp) of 45 patients with SDB: Group 1 patients with obstructive sleep apnea and an apnea-hypopnea index (AHI) > 15/h; Group 2 subjects with an AHI < 5/h; Group 3 patients on CPAP treatment for sleep apnea. RESULTS: 39 patients were included in the final analysis. Patients in Group 1 had a higher %time of sleep with SaO2 <90% and a significantly lower mean and minimum overnight oxygen saturation than subjects in Group 2 and patients in Group 3 (P<0.05). Despite significant differences in overnight oxygenation, VEGFbl and VEGFprp concentrations were not significantly different between the three study groups. However, plasma levels of VEGFbl were significantly higher (P = 0.02) in SDB patients with arterial hypertension (n = 19; VEGFbl: 14.0+/-3.3 pg/ml) than in those without arterial hypertension (n = 20; VEGFbl: 10.9+/-5.2 pg/ml). There were no relationships between VEGF levels and polysomnographic oxygenation parameters. In univariate analysis we observed significant relationships for VEGFbl with BMI (C: 0.393; P<0.05) and serum fibrinogen (C: 0.399; P<0.05). CONCLUSIONS: Circulating plasma VEGF levels in patients with sleep disordered breathing may be unrelated to night time hypoxemia (257 Words).     

A new method of negative expiratory pressure test analysis detecting upper airway flow limitation to reveal obstructive sleep apnea

BACKGROUND: Expiratory flow limitation (EFL) by negative expiratory pressure (NEP) testing, quantified as the expiratory flow-limited part of the flow-volume curve, may be influenced by airway obstruction of intrathoracic and extrathoracic origins. NEP application during tidal expiration immediately determines a rise in expiratory flow (V) followed by a short-lasting V drop (deltaV), reflecting upper airway collapsibility. PURPOSES: This study investigated if a new NEP test analysis on the transient expiratory DeltaV after NEP application for detection of upper airway V limitation is able to identify obstructive sleep apnea (OSA) subjects and its severity. METHODS: Thirty-seven male subjects (mean +/- SD age, 46 +/- 11 years; mean body mass index [BMI], 34 +/- 7 kg/m2) with suspected OSA and with normal spirometric values underwent nocturnal polysomnography and diurnal NEP testing at - 5 cm H2O and - 10 cm H2O in sitting and supine positions. RESULTS: deltaV (percentage of the peak V [%Vpeak]) was better correlated to apnea-hypopnea index (AHI) than the EFL measured as V, during NEP application, equal or inferior to the corresponding V during control (EFL), and expressed as percentage of control tidal volume (%Vt). AHI values were always high (> 44 events/h) in subjects with BMI > 35 kg/m2, while they were very scattered (range, 0.5 to 103.5 events/h) in subjects with BMI < 35 kg/m2. In these subjects, AHI still correlated to deltaV (%Vpeak) in both sitting and supine positions at both NEP pressures. CONCLUSIONS: OSA severity is better related to deltaV (%Vpeak) than EFL (%Vt) in subjects referred to sleep centers. DeltaV (%Vpeak) can be a marker of OSA, and it is particularly useful in nonseverely obese subjects.     

Impact of menopause on the prevalence and severity of sleep apnea.

STUDY OBJECTIVES: To compare the prevalence and severity of sleep apnea between premenopausal and postmenopausal women, and to determine whether these differences are affected by the body mass index (BMI) and neck circumference. DESIGN: Cross-sectional study utilizing a sleep clinic patient database. SETTING: University hospital. PATIENTS: A total of 1,315 women, classified into premenopausal and postmenopausal groups based on age (< 45 years and > 55 years, respectively). MEASUREMENTS: Anthropometric measurements included height, weight, and neck circumference. Sleep measurements included full nocturnal polysomnography. Sleep apnea was defined as an apnea-hypopnea index (AHI) > 10/h. RESULTS: There were 797 premenopausal and 518 postmenopausal women. The latter group was more obese (mean +/- SE BMI, 32.2 +/- 0.4 kg/m(2) vs 30.2 +/- 0.4 kg/m(2); p < 0.0001) and had larger neck circumference (37.1 +/- 0.2 cm vs 35.8 +/- 0.2 cm; p < 0.0001). The prevalence of sleep apnea was greater in postmenopausal women than premenopausal women (47% vs 21%; chi(2) < 0.0001). There were proportionately more postmenopausal than premenopausal women in all ranges of apnea severity (AHI, 10 to 30/h, 30 to 50/h, and > 50/h). Postmenopausal women had a significantly higher mean AHI compared to premenopausal women (17.0 +/- 0.9/h vs 8.7 +/- 0.6/h; p < 0.0001); this significant difference persisted even after adjusting for BMI and neck circumference. CONCLUSION: There may be functional, rather than anatomic, differences in the upper airway between premenopausal and postmenopausal women, which may account for the observed differences in apnea prevalence and severity.     

Effect of Sandostatin® LAR® on sleep apnoea in acromegaly: correlation with computerized tomographic cephalometry and hormonal activity

OBJECTIVES: Sleep apnoea has been reported to occur in subjects with acromegaly. This study evaluates the relationship among biochemical activity, sleep apnoeic activity and upper airway anatomic profile in acromegaly, and the effect of Sandostatin LAR, a long-acting somatostatin analogue, on these parameters. PATIENTS: Fourteen subjects with acromegaly were recruited. MEASUREMENTS: Subjects were assessed at baseline and those with apnoea-hypopnoea index (AHI) > or = 5 were reassessed after 6 months of treatment with Sandostatin LAR 20-30 mg IMI 4-weekly. Biochemical activity was assessed with levels of GH and IGF-1. Sleep disordered breathing was assessed with overnight polysomnography. Upper airway anatomic profile was defined with computerized tomographic cephalometry. RESULTS: Of 14 subjects (age 42.0 +/- 8.1 years, mean +/- SD; 11 men) at baseline, there was a positive correlation between GH and tongue length (VT; P = 0.004), and between AHI and cephalometric indices: length of soft palate (PMU; P = 0.002); mandibular plane-hyoid bone distance (MPH; P = 0.017), maximum thickness of soft palate (Max-SP; P = 0.018) and VT (P = 0.027). Eight patients had sleep disordered breathing (AHI > or = 5) which was predominantly obstructive in nature (AHI = 29.4 +/- 22.6). After treatment, there were significant improvements in hormonal profile: GH, mU/l (before, 51.5 +/- 27.8; after, 8.0 +/- 7.4; P = 0.017) and IGF-1, nmol/l (before, 95.5 +/- 23.4; after, 35.0 +/- 12.4; P = 0.012); sleep-disordered breathing: AHI (before, 29.4 +/- 22.6; after, 13.4 +/- 11.12; P = 0.025), snoring episodes (before, 486 +/- 240; after, 165 +/- 170; P = 0.05); cephalometric indices, mm: MPH (before, 18.8 +/- 12.1; after, 14.8 +/- 8.4; P = 0.018), VT (before, 72.3 +/- 4.4; after, 69.7 +/- 4.3; P = 0.05). There was a positive correlation between the reduction in GH and AHI (r = 0.738, P = 0.037). CONCLUSIONS: The findings demonstrated that there was correlation between sleep apnoea severity and soft tissue overgrowth at the upper airway region in acromegaly. They also suggest that Sandostatin LAR improved obstructive sleep apnoea in acromegaly, and the effect might be partly mediated via a reduction in upper airway soft tissue, in particular that of the tongue, concomitant with a reduction in GH levels.     

Variation in severity and type of sleep-disordered breathing throughout 4 nights in patients with heart failure

BACKGROUND: Over 50% of patients with chronic heart failure (CHF) have sleep-disordered breathing (SDB). Any variation in the type of SDB in CHF will have implications for patient management. Currently there is good evidence for treatment of obstructive sleep apnea (OSA) in CHF with continuous positive airway pressure; however, for central sleep apnea (CSA) the treatment is less clear. AIMS: The aim of this study was to investigate the variation in the severity and type of SDB (OSA vs. CSA) throughout 4 consecutive nights in CHF patients with SDB. METHODS: Nineteen male CHF patients (mean+/-sd: age 61+/-9 years; left ventricular ejection fraction: 34+/-10% and percent predicted peak VO2: 67+/-19%) underwent cardiorespiratory monitoring in their own home throughout 4 consecutive nights. RESULTS: There was minimal variation in apnea-hypopnea index (AHI) throughout 4 nights in CHF patients with SDB [intraclass correlation coefficient (95% confidence interval (CI)): 0.97 (95% CI 0.76 and 0.97)]. Eight patients [42% (95% CI 20% and 64%)] demonstrated a shift in the type of their SDB, from CSA to OSA or vice versa; these patients had significantly smaller neck circumference (group mean+/-sd) 42+/-2 vs. 44+/-2 cm; p=0.04), and had significant variation in the central AHI [intraclass correlation coefficient: 0.51 (95% CI 0.16 and 0.85)]. CONCLUSIONS: A single night of cardiorespiratory monitoring is representative of moderate-to-severe SDB in patients with CHF. However, a high proportion of patients shift their type of SDB over 4 nights. These findings may have implications for the management of SDB in CHF.     

Cephalometric abnormalities in non-obese and obese patients with obstructive sleep apnoea.

The aim of this work was to comprehensively evaluate the cephalometric features in Japanese patients with obstructive sleep apnoea (OSA) and to elucidate the relationship between cephalometric variables and severity of apnoea. Forty-eight cephalometric variables were measured in 37 healthy males and 114 male OSA patients, who were classed into 54 non-obese (body mass index (BMI) <27 kg x m(-2), apnoea-hypopnoea index (AHI)=25.3+/-16.1 events x h(-1)) and 60 obese (BMI > or = 27 kg x m(-2), AHI=45.6+/-28.0 events h(-1)) groups. Diagnostic polysomnography was carried out in all of the OSA patients and in 19 of the normal controls. The non-obese OSA patients showed several cephalometric defects compared with their BMI-matched normal controls: 1) decreased facial A-P distance at cranial base, maxilla and mandible levels and decreased bony pharynx width; 2) enlarged tongue and inferior shift of the tongue volume; 3) enlarged soft palate; 4) inferiorly positioned hyoid bone; and 5) decreased upper airway width at four different levels. More extensive and severe soft tissue abnormalities with a few defects in craniofacial bony structures were found in the obese OSA group. For the non-obese OSA group, the stepwise regression model on AHI was significant with two bony structure variables as determinants: anterior cranial base length (S-N) and mandibular length (Me-Go). Although the regression model retained only linear distance between anterior vertebra and hyoid bone (H-VL) as an explainable determinant for AHI in the obese OSA group, H-VL was significantly correlated with soft tissue measurements such as overall tongue area (Ton), inferior tongue area (Ton2) and pharyngeal airway length (PNS-V). In conclusion, Japanese obstructive sleep apnoea patients have a series of cephalometric abnormalities similar to those described in Caucasian patients, and that the aetiology of obstructive sleep apnoea in obese patients may be different from that in non-obese patients. In obese patients, upper airway soft tissue enlargement may play a more important role in the development of obstructive sleep apnoea, whereas in non-obese patients, bony structure discrepancies may be the dominant contributing factors for obstructive sleep apnoea.     

Obstructive sleep apnea and cephalometric roentgenograms. The role of anatomic upper airway abnormalities in the definition of abnormal breathing during sleep

In a six-month period, 157 obstructive sleep apnea syndrome (OSAS) patients seen consecutively in clinic had standardized cephalometric roentgenograms and underwent polygraphic monitoring during sleep. Different variables, including cephalometric landmarks, body mass index (BMI), and polygraphic results (particularly degree of O2 saturation and number of abnormal breathing events), were statistically analyzed. As a rule, OSAS patients had upper airway anatomic abnormalities and an elevated BMI: massive obesity was associated with less anatomic abnormality, less nocturnal sleep disruption, and longer total sleep time (TST). Patients having a high respiratory disturbance index (RDI) were more likely to have upper airway anatomic abnormalities; they slept for a shorter time and had increased stage 1 non-rapid eye movement (NREM) sleep but decreased stage 3 and 4 and REM sleep. Long mandibular plane to hyoid bone (MP-H) distance and width of the posterior airway space (PAS) (space behind the base of the tongue) were statistically significant predictors of elevated RDI. The cephalometric variables were much less useful for predicting frequency of O2 saturation drops below 80 percent. The patient population can be subdivided into (a) patients with clear anatomic abnormalities and low BMI, (b) patients with morbid obesity with few abnormal cephalometric measurements, and (c) patients who have variably increased BMI and abnormal cephalometric measurements. This is the largest group. We concluded that standardized cephalometric roentgenograms can be useful in determining the appropriate treatment for OSAS patients.     

阻塞性睡眠呼吸障碍患者频繁觉醒的原因探讨

目的探讨导致睡眠呼吸障碍患者睡眠中频繁发生觉醒的原因。方法对因有白天过度困倦而就诊的25例患者作全晚多导睡眠图(PSG)检查和呼吸模式分析,并与7名健康正常人对照。按国际标准人工判断觉醒。结果上气道阻力综合征(UARS)组10例,呼吸暂停／低呼吸指数(AHI)（2.5±1.4）次/h,动脉血氧饱和度(SaO2)<90%累计时间%(SLT90%)（0.1±0.1）%,觉醒指数(ArI)（30±16）次/h;阻塞性睡眠呼吸暂停综合征(OSAS)组15例,AHI（32.8±19.1）次/h,SLT90%（11.3±16.5）%,ArI（35±17）次/h;正常人组7名,AHI（5.9±4.4）次/h,SLT90%（0.2±0.4）%,ArI（13±5）次/h。OSAS和UARS组的ArI无统计学差异(H=0.49,P=0.48),均高于正常对照组的ArI(H分别为7.36和5.22,P值分别为0.001和0.02),但UARS组AHI、SLT90%明显低于OSAS组(H>5.00,P<0.05),与正常组相近(P>0.05)。结论睡眠时上气道吸气性阻力增高,是导致睡眠频繁觉醒的主要原因。