Background —Obstructive sleep apnea syndrome (OSAS) is a common disorder in obese subjects. Visceral fat accumulation (VFA) is a better predictor of coronary heart disease than body mass index. Leptin is a hormone involved in the control of body weight and fat distribution. The effect of nasal continuous positive airway pressure (NCPAP) treatment on VFA and serum leptin levels in OSAS patients has not been known. Methods and Results —VFA and subcutaneous fat accumulation (SFA) were assessed by CT before and after NCPAP treatment in 22 OSAS patients (mean apnea and hypopnea index >50 episodes/h). Serum leptin levels of another 21 OSAS patients were measured before and after 3 to 4 days of NCPAP to gain insight into the mechanism by which NCPAP affects fat distribution. VFA and SFA decreased significantly after 6 months of NCPAP treatment (236±16 to 182±14cm ² , P =0.0003 and 215±21 to 189±18 cm ² , P =0.003, respectively). VFA decreased significantly in the body weight reduction group (n=9, P <0.01) and the no body weight reduction group (n=13, P <0.03). In contrast, SFA changed significantly in the body weight reduction group only ( P <0.01). Leptin levels decreased significantly following 3 to 4 days of NCPAP ( P <0.01), whereas body weight, fasting insulin, and cortisol levels did not change significantly. Conclusions —Correction of sleep disordered breathing by NCPAP may be used to reduce VFA in OSAS patients. OSAS may have significant effects on the serum leptin levels.

The prevalence of sleep disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern countries, including Japan. Since 1998, when health insurance coverage became available, the number of patients using continuous positive airway pressure (CPAP) therapy for sleep apnea has increased sharply, with the number of patients about to exceed 500,000 in Japan. Although the "Guidelines for Diagnosis and Treatment of Sleep Apnea Syndrome (SAS) in Adults" was published in 2005, a new guideline was prepared in order to indicate the standard medical care based on the latest trends, as supervised by and in cooperation with the Japanese Respiratory Society and the "Survey and Research on Refractory Respiratory Diseases and Pulmonary Hypertension" Group, of Ministry of Health, Labor and Welfare and other related academic societies, including the Japanese Society of Sleep Research, in addition to referring to the previous guidelines. Because sleep apnea is an interdisciplinary field covering many areas, this guideline was prepared including 36 clinical questions (CQs). In the English version, therapies and managements for SAS, which were written from CQ16 to 36, were shown. The Japanese version was published in July 2020 and permitted as well as published as one of the Medical Information Network Distribution Service (Minds) clinical practice guidelines in Japan in July 2021.

Background: Health status, dyspnea and psychological status are important clinical outcomes in chronic obstructive pulmonary disease (COPD). However, forced expiratory volume in one second (FEV₁) measured by spirometry, the standard measurement of airflow limitation, has only a weak relationship with these outcomes in COPD. Recently, in addition to spirometry, impulse oscillometry (IOS) measuring lung resistance (R) and reactance (X) is increasingly being used to assess pulmonary functional impairment. Methods: We aimed to identify relationships between IOS measurements and patient-reported outcomes in 65 outpatients with stable COPD. We performed pulmonary function testing, IOS, high-resolution computed tomography (CT), and assessment of health status using the St. George's Respiratory Questionnaire (SGRQ), dyspnea using the Medical Research Council (MRC) scale and psychological status using the Hospital Anxiety and Depression Scale (HADS). We then investigated the relationships between these parameters. For the IOS measurements, we used lung resistance at 5 and 20 Hz (R5 and R20, respectively) and reactance at 5 Hz (X5). Because R5 and R20 are regarded as reflecting total and proximal airway resistance, respectively, the fall in resistance from R5 to R20 (R5-R20) was used as a surrogate for the resistance of peripheral airways. X5 was also considered to represent peripheral airway abnormalities. Results: R5-R20 and X5 were significantly correlated with the SGRQ and the MRC. These correlation coefficients were greater than when using other objective measurements of pulmonary function, R20 on the IOS and CT instead of R5-R20 and X5. Multiple regression analyses showed that R5-R20 or X5 most significantly accounted for the SGRQ and MRC scores. Conclusions: IOS measurements, especially indices of peripheral airway function, are significantly correlated with health status and dyspnea in patients with COPD. Therefore, in addition to its simplicity and non-invasiveness, IOS may be a useful clinical tool not only for detecting pulmonary functional impairment, but also to some extent at least estimating the patient's quality of daily life and well-being.

The individual prevalence of sleep-disordered breathing (SDB), short sleep duration, and obesity is high and increasing. The study aimed to investigate potential associations between SDB, objective sleep duration, obesity, diabetes and hypertension across genders, and the effect of pre- or post-menopausal status. A cross-sectional study evaluated 7051 community participants with wrist actigraphy for a week, and nocturnal oximetry ≥ 2 nights. SDB was assessed by 3 per cent oxygen desaturation index (ODI) corrected for sleep duration obtained from wrist actigraphy. Moderate-to-severe SDB was defined as ODI3% levels ≥ 15 per hour. Both logODI3% and body mass index showed independent negative associations with sleep duration (β = −0.16, p < 0.001 and β = −0.07, p < 0.001, respectively). Moderate-to-severe SDB (men/premenopausal women/postmenopausal women; 23.7/1.5/9.5%, respectively) was associated with a higher risk of diabetes in premenopausal women (OR 28.1; 95%CI 6.35–124.6; p < 0.001) and postmenopausal women (OR 3.25; 95%CI 1.94–5.46; p < 0.001), but not in men (OR 1.47; 95%CI 0.90–2.40; p = 0.119). Moderate-to-severe SDB was associated with a higher risk of hypertension in men (OR 3.11; 95%CI 2.23–4.33; p < 0.001), premenopausal women (OR 3.88; 95%CI 1.42–10.6; p = 0.008), and postmenopausal women (OR 1.96; 95%CI 1.46–2.63; p < 0.001). Short sleep duration was not associated with diabetes or hypertension. The associations of obesity with diabetes or hypertension were indirectly mediated by SDB (24.0% and 21.5%, respectively), with possible sex differences emerging (men/women; 15.3/27.8% and 27.0/16.9%, respectively). Notwithstanding the cross-sectional design, SDB and obesity, but not short sleep duration, were independently associated with diabetes and hypertension, with gender and menopausal status–related differences in risk emerging.