Cluster analysis identifies a pathophysiologically distinct subpopulation with increased serum leptin levels and severe obstructive sleep apnea.

PURPOSE: To investigate the different pathophysiologies of obstructive sleep apnea (OSA) phenotypes using cluster analysis. Differences between leptin/adiponectin levels in the resulting OSA phenotypes were also examined. METHODS: In total, 1057 OSA patients were selected, and a retrospective survey of clinical records, polysomnography results, and blood gas data was conducted. Patients were grouped into four clusters by their OSA severity, PaCO2, body mass index (BMI), and sleepiness. A k-means cluster analysis was performed, resulting in a division into four subpopulations. The Tukey or Games-Howell tests were used for intergroup comparisons. RESULTS: Among the 20 clinical OSA items, four common factors (Epworth Sleepiness Scale [ESS], BMI, Apnea-Hypopnea Index [AHI], and PaCO2) were extracted by principal component analysis, and a cluster analysis was performed using the k-means method, resulting in four distinct phenotypes. The Clusters 1 (middle age, symptomatic severe OSA) and 4 (young, obese, symptomatic very severe OSA) exhibited high leptin levels. C-reactive protein levels were also elevated in Cluster 4, indicating a different pathophysiological background. No apparent differences between clusters were observed regarding adiponectin/leptin ratios and adiponectin levels. Classification into groups based on phenotype showed that Epworth Sleepiness Scale [ESS] score and disease severity were not correlated, suggesting that sleepiness is affected by multiple elements. CONCLUSIONS: The existence of multiple clinical phenotypes suggests that different pathophysiological backgrounds exist such as systemic inflammation and metabolic disorder. This classification may be used to determine the efficacy of continuous positive airway pressure treatment that cannot be determined by the AHI.

Association between a composite measure of sleep health and depressive symptoms in patients with obstructive sleep apnea treated with CPAP therapy: Real-world data.

OBJECTIVE: Sleep health is known to be multidimensional, and there is increasing clinical interest in composite sleep health scores that capture the number of adverse sleep characteristics. We investigated whether a composite sleep health score was associated with depressive symptoms in patients with obstructive sleep apnea (OSA) treated with continuous positive airway pressure (CPAP). METHODS: Participants were OSA patients using CPAP (n = 1768, (92.1 % men, age 52.7 ± 10.7 years) attending sleep clinics in Japan. A cross-sectional survey conducted in 2020 assessed self-reported sleep and depressive symptoms. Sleep health was categorized as "good' or "poor' on five dimensions: satisfaction, daytime sleepiness, mid-sleep time, efficiency, and duration. A composite sleep health score was calculated by summing the "poor' dimensions. Depressive symptoms were assessed using two items from the Patient Health Questionnaire (PHQ-2). Associations between sleep health and depressive symptoms were assessed using multivariable logistic regression analysis. RESULTS: Individual sleep health symptoms of poor satisfaction and efficiency were significantly associated with depressed mood; poor satisfaction, daytime sleepiness, and duration were significantly associated with loss of interest; and poor satisfaction, efficiency, and duration were significantly associated with depressive symptoms. Composite sleep health scores were associated with greater odds of depressive symptoms in a graded manner. CONCLUSIONS: Individual and composite sleep health scores were associated with depressive symptoms. Measures of multidimensional sleep health may provide a better understanding of the association between poor sleep and depressive symptoms among patients with OSA using CPAP, accounting for CPAP adherence, leading to improved intervention strategies.

A case of Kleine-Levin syndrome arising during chemotherapy: efficacy of oral L-carnitine.

A woman in her 50 s with Kleine-Levin syndrome (KLS) was referred to our sleep clinic for recurrent episodes of sleep hypersomnia lasting for two to 3 days, despite attempts to remain awake. These episodes were unaccompanied by anxiety or depression, increased appetite, increased sex drive, irritability, or hallucinations, and had first appeared during chemotherapy for malignant lymphoma. Video polysomnography revealed mild obstructive sleep apnea syndrome (apnea-hypopnea index 7.9/h), but no other abnormalities. All blood tests and brain imaging investigations, including brain MRI and A 123I-ioflupane SPECT, yielded normal results. Oral L-carnitine was found to be effective for shortening the period of hypersomnolence, reducing the degree of hypersomnolence, and prolonging the inter-episode period. Since it has been reported that alkylating agents may induce carnitine deficiency, the present observations appear to support the involvement of carnitine in the onset of KLS.

The validity and reliability of the Japanese version of RU-SATED.

OBJECTIVE: We developed a Japanese version of RU-SATED (RU-SATED-J), a simple self-rated scale for measurement of multidimensional sleep health, and examined its reliability and psychometric validity. METHOD: The RU-SATED-J was developed by a rigorous reverse translation process. It consists of six questions, each with three Likert-type response options. The total score (range 0-12) was calculated by summing the item scores. Psychometric characteristics were tested in an observational cross-sectional study involving factory workers in Japan (n = 177, mean age 42.8 ± 11.6 years, range 19-65 years). The distribution and reliability of the scale scores were examined in terms of Cronbach's alpha coefficient. The convergent and divergent validity of the scale score were assessed by examining the correlations of various factors with the Insomnia Severity Index (ISI) and the Epworth Sleepiness Scale (ESS). RESULTS: The distribution of scores was left-skewed, with a mean of 8.21 ± 2.72 points, and range of 0-12. The internal reliability of the scale was α = 0.758. The total score showed a significant negative correlation with the ISS (rs = -0.542, P < 0.001) and the ESS (rs = -0.178, P = 0.018). Exploratory factor analysis (EFA) demonstrated a two-factor structure. Confirmatory factor analysis (CFA) showed that the goodness of fit of the higher-order factor model had a Root Mean Square Error of Approximation (RMSEA) of <0.001 and a Comparative Fit Index (CFI) of 1.00, confirming its factorial validity. CONCLUSION: The RU-SATED is a promising new instrument for measuring multi-dimensional sleep health perception among Japanese adults. Further general population studies using this Japanese version of the questionnaire should be considered.

Multimodal Telemonitoring for Weight Reduction in Patients With Sleep Apnea: A Randomized Controlled Trial.

BACKGROUND: Telemonitoring the use of CPAP devices and remote feedback on device data effectively optimizes CPAP adherence in patients with OSA. RESEARCH QUESTION: Can expanding the scope of telemonitoring and remote feedback to body weight (BW), BP, and physical activity enhance efforts for BW reduction in Patients with OSA receiving CPAP? STUDY DESIGN AND METHODS: Participants were recruited from patients at 16 sleep centers in Japan with OSA and obesity who were receiving CPAP therapy. Obesity was defined as a BMI of ≥ 25 kg/m2, based on Japanese obesity guidelines. Implementation of CPAP telemonitoring was enhanced with electronic scales, BP monitors, and pedometers that could transmit data from devices wirelessly. Participants were randomized to the multimodal telemonitoring group or the usual CPAP telemonitoring group and were followed up for 6 months. Attending physicians provided monthly telephone feedback calls to the usual CPAP telemonitoring group on CPAP data obtained remotely. In the multimodal telemonitoring group, physicians additionally encouraged participants to reduce their BW, after sharing the remotely obtained data on BW, BP, and step count. The primary outcome was set as ≥ 3% BW reduction from baseline. RESULTS: One hundred sixty-eight participants (BMI, 31.7 ± 4.9 kg/m2) completed the study, and ≥ 3% BW reduction occurred in 33 of 84 participants (39.3%) and 21 of 84 participants (25.0%) in the multimodal telemonitoring and usual CPAP telemonitoring groups, respectively (P = .047). Whereas no significant differences were found between the two groups in the change in office and home BP, daily step counts during the study period were significantly higher in the multimodal telemonitoring group than in the usual CPAP telemonitoring group (4,767 steps/d [interquartile range (IQR), 2,864-6,617 steps/d] vs 3,592 steps/d [IQR, 2,117-5,383 steps/d]; P = .02) INTERPRETATION: Multimodal telemonitoring may enhance BW reduction efforts in patients with OSA and obesity. TRIAL REGISTRY: UMIN Clinical Trials Registry; No.: UMIN000033607; URL: www.umin.ac.jp/ctr/index.htm.

Identifying unrecognized airflow obstruction in cases with lifestyle-related diseases using a data mining system with electronic medical records.

BACKGROUND: Airflow obstruction is the most important pathophysiologic factor in chronic obstructive pulmonary disease (COPD). Although the prevalence of airflow obstruction has been increasing worldwide, airflow obstruction is often under-recognized in clinical practice because of insufficient use of spirometry. The aim of the present study was to identify unrecognized airflow obstruction in cases with lifestyle-related diseases using a data mining system that we have developed for use with electronic medical records. METHODS: Clinical, spirometric data on 27,111 patients aged 40 years or older treated during the period from January 1999 to December 2008 was retrospectively collected from the electronic medical records of the Nihon University School of Medicine clinical data warehouse. Airflow obstruction was defined according to the criteria established by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). RESULTS: Of the 27,111 patients, 6,098 (22.5%) showed airflow obstruction. Airflow obstruction was significantly more frequent in males, the elderly and smokers. The prevalence of airflow obstruction in patients with atherosclerosis (29.3%) was greater than that in patients with dyslipidemia (24.3%), diabetes mellitus (23.1%) or hypertension (27.1%). Only 14% of patients with airflow obstruction had a previous diagnosis of COPD. CONCLUSIONS: Latent COPD patients with airflow obstruction are highly prevalent, not only in those over 70 years of age with lifestyle-related diseases, but also in middle-aged patients. Spirometry should be widely used for patients with lifestyle-related diseases and a history of smoking, to effectively detect undiagnosed COPD.

Obstructive sleep apnoea is associated with risk factors comprising the metabolic syndrome.

BACKGROUND AND OBJECTIVE: Several features of OSA syndrome suggest that it is a manifestation of the metabolic syndrome (MS). In this study, we investigated the prevalence of the MS among male Japanese patients with OSA, as well as the relationship between OSA in non-obese patients and components of the MS other than obesity (hypertension, dyslipidaemia and glucose intolerance). METHODS: The study included 416 Japanese men who were diagnosed as having OSA by polysomnography. Among these, 101 non-obese patients were selected and the severity of OSA, as well as the prevalence of hypertension, dyslipidaemia and glucose intolerance, was assessed. RESULTS: The MS was associated with OSA in 218/416 patients (52.4%). A significant increase in the prevalence of the MS was associated with increased severity of OSA, as categorized according to AHI. In the non-obese patients with OSA (mean age 57.6 years, BMI 22.7 kg/m(2), AHI 34.3 events/h), hypertension, dyslipidaemia and glucose intolerance were identified in 70 (69.3%), 43 (42.6%) and 20 patients (19.8%), respectively. At least two of these factors were identified in 40 patients (39.6%). Non-obese patients with severe OSA had a significantly higher prevalence of two or more of these factors (33/59 patients, 55.9%). CONCLUSIONS: Although Asians are generally less obese than Caucasians, the prevalence of the MS was high among Japanese patients with OSA, and even among non-obese patients, OSA was associated with risk factors for the MS.

A Randomized Controlled Trial of Telemedicine for Long-Term Sleep Apnea Continuous Positive Airway Pressure Management.

Rationale: The effects of telemedicine on adherence in patients with obstructive sleep apnea with long-term continuous positive airway pressure (CPAP) use have never been investigated.Objectives: To examine effects of a telemedicine intervention on adherence in long-term CPAP users.Methods: In a prospective, randomized, multicenter noninferiority trial conducted in 17 sleep centers across Japan, patients who had used CPAP for >3 months and were receiving face-to-face follow-up by physicians every 1 or 2 months were randomized by a coordinating center in a blind manner to the following three groups: 1) follow-up every 3 months accompanied by a monthly telemedicine intervention (telemedicine group: TM-group), 2) follow-up every 3 months (3-month group: 3M-group), or 3) monthly follow-up (1-month group: 1M-group). Each group was followed up for 6 months. The change in percentage of days with ≥4 h/night of CPAP use from baseline to the end of the study period was evaluated. A decline of ≥5% from baseline was considered deterioration of adherence. Noninferiority of TM- and 3M-groups compared with the 1M-group according to the number of patients with deterioration of adherence was evaluated with the Farrington and Manning test (noninferiority margin 15%).Results: A total of 483 patients were analyzed (median duration of CPAP use, 29 [interquartile range, 12-71] mo), and deterioration of adherence was found in 41 of 161 (25.5%), 55 of 166 (33.1%), and 35 of 156 (22.4%) patients in the TM-, 3M-, and 1M-groups, respectively. The noninferiority of the TM-group compared with the 1M-group was verified (difference in percentage of patients with adherence deterioration, 3.0%; 95% confidence interval [CI], -4.8% to 10.9%; P < 0.01). Conversely, the 3M-group did not show noninferiority to the 1M-group (percentage difference, 10.7%; 95% CI, 2.6% to 18.8%; P = 0.19). In the stratified analysis, adherence in TM- and 1M-group patients with poor adherence at baseline improved (TM: 45.8% ± 18.2% to 57.3% ± 24.4%; P < 0.01; 1M: 43.1% ± 18.5% to 53.6% ± 24.3%; P < 0.01), whereas that of the 3M-group did not (39.3% ± 20.8% to 39.8% ± 24.8%; P = 0.84).Conclusions: Intensive telemedicine support could help to optimize CPAP adherence even after long-term CPAP use.Clinical trial registered with www.umin.ac.jp/ctr/index.htm (trial number: UMIN000023118).

Predicting optimal continuous positive airway pressure in Japanese patients with obstructive sleep apnoea syndrome.

BACKGROUND AND OBJECTIVE: Several algorithms that predict the optimal CPAP have been developed for Caucasian patients with OSA syndrome, but these algorithms do not allow for racial differences in craniofacial anatomy. We investigated whether an equation that included data on craniofacial structure, physique and severity of OSA could more accurately predict the optimal CPAP for Japanese patients with OSA syndrome. METHODS: In 170 Japanese patients with OSA syndrome, the optimal CPAP was determined by manual titration during polysomnography. An equation predicting the optimal pressure was derived from anthropometric, polysomnographic and cephalometric data. This equation was validated in another 110 Japanese patients with OSA syndrome. RESULTS: Stepwise multiple regression analysis identified AHI, BMI, mean SaO(2) and a cephalometric parameter: the angle between a line from point B to the menton (Me) and a line from Me to the hyoid bone (H) (BMeH), as independent predictors of optimal CPAP. The following equation was constructed to predict the optimal CPAP: 27.78 + (0.041 x BMeH) + (0.141 x BMI) + (0.040 x AHI) - (0.312 x mean SaO(2)). This equation accounted for 47% of the variance in optimal pressure (R(2) = 0.47, P < 0.0001). The measured optimal pressure and the pressure calculated using this equation were very similar in the other 110 patients with OSA syndrome (9.5 +/- 3.0 and 9.2 +/- 2.1 cmH(2)O, respectively). CONCLUSION: Optimal CPAP was more accurately predicted by combining a cephalometric parameter with BMI and polysomnographic data in Japanese patients with OSA, suggesting that craniofacial structure may be important in the pathogenesis of OSA syndrome among Asians.

Sleep disordered breathing in cardiac surgery patients: The NU-SLEEP trial.

BACKGROUND: Sleep disordered breathing (SDB) is associated with lifestyle-related diseases and its treatment influence the prognosis of cardiac disease, but little investigation of SDB has been conducted in cardiac surgery patients. METHODS AND RESULTS: A prospective study was performed in 1005 patients undergoing cardiac surgery. The primary endpoint was the severity of SDB determined from the apnea/hypopnea index. The secondary endpoints were patient background factors, cardiovascular risk factors, ejection fraction, atrial and brain natriuretic peptides, oxidative stress and inflammatory markers, and postoperative atrial fibrillation. While 227 patients (22.6%) did not have SDB, there were 361 patients (35.9%) with mild SDB, 260 patients (25.9%) with moderate SDB, and 157 patients (15.6%) with severe SDB. Patients with severe SDB had a lower ejection fraction and higher levels of atrial and brain natriuretic peptides than the other groups. Postoperative atrial fibrillation occurred in 28 patients without SDB (13.6%), 43 patients with mild SDB (13.5%), 74 patients with moderate SDB (31.9%), and 73 patients with severe SDB (52.5%), being significantly more frequent in the severe group than the other groups. CONCLUSIONS: SDB was frequent in cardiac surgery patients. Activation of the renin-angiotensin-aldosterone system, postoperative atrial fibrillation atrial, and cardiac dysfunction were associated with severe SDB. Markers of inflammation and oxidative stress also increased as SDB became more severe.

Nasal CPAP improves the quality of life and lessens the depressive symptoms in patients with obstructive sleep apnea syndrome.

OBJECTIVE: To assess changes in response to nasal continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea syndrome (OSAS) concerning excessive daytime sleepiness (EDS), depressive state, and quality of life (QOL). PATIENTS AND METHODS: We assessed for EDS using the Epworth sleepiness scale (ESS), for mood using The Zung self-depression scale (SDS), and for QOL using Short-Form 36 (SF-36) in 132 patients with obstructive sleep apnea syndrome (OSAS) and control subjects. Patients had severe OSAS (apnea-hypopnea index, 59.4+/-23.8/h) and were more hypersomnolent and depressed, and had poorer QOL than 38 age- and gender-matched controls. RESULTS: Before treatment most QOL domains in the SF-36 were significantly associated with patients' SDS scores. With nasal CPAP, ESS and SDS scores were respectively decreased from 9.7+/-4.5 to 4.0+/-2.4 (p<0.0001) and from 49.2+/-10.4 to 45.1+/-9.6 (p<0.0005). Total SF-36 score and scores for seven of eight domains were increased significantly with treatment. Thus, nasal CPAP lessens EDS and depression, and improves QOL, in patients with severe OSAS. Further, magnitudes of changes in total SF-36 scores and in five of eight domains correlated significantly with magnitude of change in SDS score upon nasal CPAP treatment. No relationship was evident between treatment-associated score changes in SF-36 domains and ESS score change. CONCLUSION: Although patients with severe OSAS have poorer QOL than control subjects, nasal CPAP appears to improve QOL by alleviating depression.

Effects of long-term nasal continuous positive airway pressure on C-reactive protein in patients with obstructive sleep apnea syndrome.

Serum levels of C-reactive protein (CRP) were measured in 96 consecutive patients with obstructive sleep apnea syndrome (OSAS) before and after nasal continous positive airway pressure treatment. CRP levels only displayed significant correlations with body mass index (BMI) before treatment. No significant changes were observed in BMI and CRP levels after 9 months of treatment. These data suggest that CRP levels in patients with OSAS may be associated with obesity rather than OSAS itself.

Prevalence of chronic kidney diseases in patients with chronic obstructive pulmonary disease: assessment based on glomerular filtration rate estimated from creatinine and cystatin C levels.

BACKGROUND: Cardiovascular diseases, osteoporosis, and depression are identified comorbidities of chronic obstructive pulmonary disease (COPD), but there have been few reports of chronic kidney disease (CKD) as a comorbidity of COPD. The objective of this study was to investigate the prevalence of CKD in COPD patients using estimated glomerular filtration rate (eGFR) based on creatinine (Cr) and cystatin C (Cys) levels. METHODS: The prevalence of CKD and the values of various CKD-related parameters were compared between 108 stable COPD outpatients (COPD group) and a non-COPD control group consisting of 73 patients aged 60 years or more without a history of COPD or kidney disease. CKD was defined as an eGFR less than 60 mL/min/1.73 m(2). RESULTS: The Cr level was significantly higher in the COPD group, but eGFR based on serum Cr (eGFRCr) was not significantly different between the two groups (73.3±25.3 vs 79.7±15.5 mL/min/1.73 m(2)). The Cys level was significantly higher and eGFR based on serum Cys (eGFRCys) was significantly lower in the COPD group (60.0±19.4 vs 74.0±13.5 mL/min/1.73 m(2), P<0.0001). The prevalence of CKD evaluated based on eGFRCr was 31% in the COPD group and 8% in the non-COPD group with an odds ratio of 4.91 (95% confidence interval, 1.94-12.46, P=0.0008), whereas the evaluated prevalence based on eGFRCys was 53% in the COPD group and 15% in the non-COPD group with an odds ratio of 6.30 (95% confidence interval, 2.99-13.26, P<0.0001), demonstrating a higher prevalence of CKD when based on eGFRCys rather than on eGFRCr. CONCLUSION: CKD is a comorbidity that occurs frequently in COPD patients, and we believe that renal function in Japanese COPD patients should preferably be evaluated based not only on Cr but on Cr in combination with Cys.

Relationship between quality of life and mood or depression in patients with severe obstructive sleep apnea syndrome.

STUDY OBJECTIVES: To assess the quality of life (QOL) in patients with severe obstructive sleep apnea (OSAS), and the relationship between the QOL and severity of OSAS, excessive daytime sleepiness (EDS), and mood. METHODS: Sixty patients with OSAS and 34 normal control subjects were assessed for QOL using the Medical Outcomes Study Short-Form 36 Health Survey questionnaire (SF-36), for EDS using the Epworth sleepiness scale (ESS), and for mood using the Zung self-rated depression scale (SDS). The associations between each domain and the total score on the SF-36 and the baseline characteristics, polysomnographic parameters, ESS score, and SDS score were examined by simple regression analysis and stepwise multiple regression analysis. RESULTS: Six of eight domains and the total score on the SF-36 were significantly lower than those in the control subjects. The ESS and SDS scores were also more impaired in the patients than in the control subjects. There was no relationship between each domain on the SF-36 and the severity of OSAS and ESS score. Five of eight domains and the total score on the SF-36 were significantly correlated with the SDS score. Stepwise multiple regression analysis selected three variables, the SDS score (partial R(2) = 0.505), the lowest arterial oxygen saturation during sleep (partial R(2) = 0.064), and ESS score (partial R(2) = 0.053), as independent factors for predicting the total score on the SF-36. These three variables accounted for 62.2% of the total variance in the total score on SF-36 (R(2) = 0.622, p < 0.0001) CONCLUSIONS: The QOL of patients with severe OSAS was decreased compared with normal control subjects. The QOL of patients was strongly correlated with the depression scale on simple regression analysis. However, EDS score and oxygen desaturation during sleep also affected the QOL, although the magnitude of its effect was small.

[Clinical usefulness of a cardiopulmonary sleep study in patients with sleep apnea syndrome].

Although polysomnography is indispensable in the diagnosis of sleep apnea syndrome (SAS), a common disease in Japan, it is a time-consuming procedure. We therefore assessed the clinical usefulness of a cardiopulmonary sleep study (CPSS), which monitors indices of respiratory and circulatory kinetics during sleep. Of ninety male patients (50 +/- 11 years old, BMI: 27 +/- 4), those with apnea indices (AI) > 5, as determined using an apnomonitor, underwent CPSS with a Night Watch System. Sixty-nine patients with indications for nasal CPAP (NCPAP) therapy underwent overnight CPSS and the optimum pressure was determined. AI was 31 +/- 17, whereas CPSS showed an apnea-hypopnea index of 49 +/- 24, a mean SaO2 of 93 +/- 3%, and a minimum SaO2 of 71 +/- 11%, indicating severe OSAS. The mean optimum pressure was 10 +/- 2 cm H2O, and the compliance was 86%, which was comparatively good. As CPSS can be performed on many patients in a short time, it may be useful for the early diagnosis and initial treatment of SAS.

Arrhythmia and sleep-disordered breathing in patients undergoing cardiac surgery.

BACKGROUND: Recently, the role of sleep-disordered breathing (SDB) in cardiovascular disease has attracted attention. In this study, we investigated the influence of SDB on postoperative arrhythmias after cardiac surgery. METHODS AND RESULTS: In 89 patients undergoing cardiac surgery, postoperative portable monitoring for SDB and Holter electrocardiography were performed. The primary end-points were the apnea-hypopnea index (AHI) and occurrence of arrhythmia. The secondary end-points were: (1) patient background factors; (2) average heart rate; (3) maximum heart rate (total, daytime, and nighttime); (4) minimum heart rate (total, daytime, and nighttime); (5) minimum SaO(2) during sleep; and (6) an independent predictor for arrhythmia. Twenty-six patients (29.2%) had an AHI≥15 and they were classified into the SDB group, while patients with an AHI<15 formed the non-SDB group (70.8%). Although there was no significant difference in atrial fibrillation, frequent nocturnal premature ventricular contractions were significantly more common in the SDB group (19.2%) than the non-SDB group (3.2%) (p=0.01). Maximum daytime and nighttime heart rates were also significantly higher in the SDB group. AHI was a significant predictor for frequent nocturnal premature ventricular contractions. CONCLUSIONS: This study showed that SDB is common among patients undergoing cardiac surgery, and that SDB might be closely associated with arrhythmia in these patients.

The association between sleep problems and perceived health status: a Japanese nationwide general population survey.

OBJECTIVE: Sleep problems in humans have been reported to impact seriously on daily function and to have a close association with well-being. To examine the effects of individual sleep problems on physical and mental health, we conducted a nationwide epidemiological survey and examined the associations between sleep problems and perceived health status. METHODS: Cross-sectional surveys with a face-to-face interview were conducted in August and September, 2009, as part of the Nihon University Sleep and Mental Health Epidemiology Project (NUSMEP). Data from 2559 people aged 20 years or older were analyzed (response rate 54.0%). Participants completed a questionnaire on perceived physical and mental health statuses, and sleep problems including the presence or absence of insomnia symptoms (i.e., difficulty initiating sleep [DIS], difficulty maintaining sleep [DMS], and early morning awakening [EMA]), excessive daytime sleepiness (EDS), poor sleep quality (PSQ), short sleep duration (SSD), and long sleep duration (LSD). RESULTS: The prevalence of DIS, DMS, and EMA was 14.9%, 26.6%, and 11.7%, respectively, and 32.7% of the sample reported at least one of them. At the complaint level, the prevalence of EDS, PSQ, SSD, and LSD was 1.4%, 21.7%, 4.0%, and 3.2%, respectively. Multiple logistic regression analyses revealed that DMS, PSQ, SSD, and LSD were independently associated with poor perceived physical health status; DIS, EDS, and PSQ were independently associated with poor perceived mental health status. CONCLUSIONS: This study has demonstrated that sleep problems have individual significance with regard to perceived physical or mental health status.

Clinical characteristics of obesity-hypoventilation syndrome in Japan: a multi-center study.

OBJECTIVE: To clarify the prevalence and clinical characteristics of obesity-hypoventilation syndrome (OHS) in a large number of patients with moderate to severe obstructive sleep apnea syndrome (OSAS). METHODS: Subjects comprised 611 patients with OSAS registered from 7 sleep centers and clinics and analyzed according to the definitions of the Respiratory Failure Research Group of the Japanese Ministry of Health and Welfare. Baseline characteristics, polysomnographic data during sleep, laboratory blood examinations, excessive daytime sleepiness, pulmonary functions, and arterial blood gases were compared between OHS and non-OHS patients. Determinants of daytime hypercapnia were also examined in OHS patients. RESULTS: OHS was identified in 55 of the 611 patients with OSAS (9%). OHS patients were younger, heavier, and more somnolent than non-OHS patients and displayed more severe OSAS, liver dysfunctions, higher total cholesterol, and impaired pulmonary function. However, these differences were resolved except for pulmonary function after correction for obesity. Daytime hypercapnia was associated with impaired pulmonary function. Percent vital capacity (%VC) was most closely correlated with PaCO2 in OHS. CONCLUSION: OHS patients display numerous abnormalities due to obesity compared with non-OHS patients. Impaired pulmonary function, particularly %VC, may play an important role in the development of daytime hypercapnia independent of obesity in OHS patients.

Pharyngeal pressure and flow effects on genioglossus activation in normal subjects.

Pharyngeal dilator muscles are clearly important in the pathogenesis of obstructive sleep apnea syndrome. Substantial data support the role of local mechanisms in mediating pharyngeal dilator muscle activation in normal humans during wakefulness. Using a recently reported iron lung ventilation model, we sought to determine the stimuli modulating genioglossus activity, dissociating the influences of pharyngeal negative pressure, from inspiratory airflow, resistance, and CO(2). To achieve this aim, we used two gas densities at several levels of end-tidal CO(2) and a number of intrapharyngeal negative pressures. The correlations between genioglossus electromyography (GGEMG) and epiglottic pressure across a breath remained robust under all conditions (R values range from 0.71 +/- 0.07 to 0.83 +/- 0.05). In addition, there was no significant change in the slope of this relationship despite variable gas density or CO(2) levels. Although flow also showed strong correlations with genioglossus activity, there was a significant change in the slope of the GGEMG/flow relationship with altered gas density. For the group averages across conditions (between breath analysis), the correlation with GGEMG was robust for negative pressure (R(2) = 0.98) and less strong for other variables such as flow and resistance. These data suggest that independent of central pattern generator activity, intrapharyngeal negative pressure itself modulates genioglossus activity both within breaths and between breaths.