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Rationale: Obstructive sleep apnea (OSA) can affect not only sleep quality but also sleep duration. Determining the therapeutic effects of continuous positive airway pressure (CPAP) on habitual sleep profiles may shed light on the impact of OSA on sleep duration.Objectives: To determine whether and how CPAP affects habitual sleep duration in patients with OSA.Methods: Assessments of sleep duration and sleep quality were performed on 57 newly diagnosed study subjects with OSA (46 men; median age, 63 yr; apnea-hypopnea index, >20 h-1) at baseline and 3 months after initiation of CPAP therapy. Measurements included in-laboratory sleep tests (polysomnography), assessments of habitual sleep (actigraphy with sleep diary for 7 d), and questionnaires on subjective symptoms (Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, and Hospital Anxiety and Depression Scale).Results: Actigraphic night sleep time did not change after CPAP (from 354.0 ± 64.5 min to 353.0 ± 57.0 min; P = 0.87) in the entire group, despite improvements in sleep efficiency and sleep fragmentation. Changes in habitual night sleep duration varied among the participants; habitual night sleep duration increased by 33 minutes (interquartile range, 14-45 min) in 28 participants (sleep time restorers) and decreased by 23 minutes (interquartile range, -48 to -11 min) in 29 participants (sleep time nonrestorers). Subgroup analyses revealed that sleep time restorers were characterized at baseline as having shorter and more fragmented sleep with frequent daytime napping. Nonrestorers were characterized by frequent use of hypnotic drugs and comorbid insomnia, despite longer habitual sleep duration. Actigraphic sleep fragmentation, sleep efficiency, daytime sleepiness, and the frequency of daytime napping were improved after CPAP only in the sleep time restorers, whereas subjective sleep quality was improved in the nonrestorers. Multivariate linear regression showed that shorter baseline night sleep time, baseline daytime napping, and percentage of sleep time under CPAP were positive predictors of the restoration of actigraphic night sleep time, whereas hypnotic use was a negative predictor.Conclusions: Short-term CPAP did not affect habitual night sleep duration in the group as a whole but induced intraindividual changes in relation to phenotypic features of OSA. Clinical trial registered with www.umin.ac.jp (UMIN000012639). [ABSTRACT FROM AUTHOR]

Rationale: Disrupted energy homeostasis in obstructive sleep apnea (OSA) may lead to weight gain. Paradoxically, treating OSA with continuous positive airway pressure (CPAP) may also promote weight gain, although the underlying mechanism remains unclear.Objectives: To explore the underlying mechanism by which patients with OSA gain weight after CPAP.Methods: A comprehensive assessment of energy metabolism was performed in 63 newly diagnosed OSA study participants (51 men; 60.8 ± 10.1 yr; apnea-hypopnea index >20 h(-1)) at baseline, CPAP initiation, and at a 3-month follow-up. Measurements included polysomnography, body weight, body composition, basal metabolic rate (BMR), hormones (norepinephrine, cortisol, leptin, ghrelin, insulin-like growth factor-1), dietary intake, eating behavior, and physical activity.Measurements and Main Results: BMR significantly decreased after CPAP (1,584 kcal/d at baseline, 1,561 kcal/d at CPAP initiation, and 1,508 kcal/d at follow-up; P < 0.001), whereas physical activity and total caloric intake did not significantly change. In multivariate regression, baseline apnea-hypopnea index, Δurine norepinephrine, and CPAP adherence were significant predictors of ΔBMR. The weight gainers had higher leptin levels, lower ghrelin levels, and higher eating behavior scores than the non-weight gainers, indicating a positive energy balance and disordered eating behavior among the weight gainers. Among the parameters related to energy metabolism, increased caloric intake was a particularly significant predictor of weight gain.Conclusions: Although a reduction in BMR after CPAP predisposes to a positive energy balance, dietary intake and eating behavior had greater impacts on weight change. These findings highlight the importance of lifestyle modifications combined with CPAP. Clinical trial registered with http://www.umin.ac.jp/english/ (UMIN000012639). [ABSTRACT FROM AUTHOR]

Rationale: Incretin hormones, namely glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide/glucose-dependent insulinotropic polypeptide (GIP), and dipeptidyl peptidase-4 (DPP-4) activity are important factors in glucose metabolism and have not been investigated in patients with obstructive sleep apnea (OSA).Objectives: The objective of this study was to investigate the association between OSA and incretin and DPP-4 activity.Methods: This study included 96 consecutive patients without diabetes who were suspected of having OSA. We investigated the fasting and post-prandial incremental area under the curve (IAUC) of GLP-1, GIP serum levels, and serum DPP-4 activity levels, as well as their association with OSA. Changes in clinical variables were evaluated in the 43 patients who continued continuous positive airway pressure therapy for 3 months.Measurements and Main Results: Apnea-hypopnea index was an independent determining factor for fasting GLP-1 (β = 0.31; P = 0.0019) and IAUC GIP (β = -0.21; P = 0.037) after adjusting for known confounding factors. In those with very severe OSA (apnea-hypopnea index ≥50), the IAUCs for GLP-1 and GIP were significantly decreased, while fasting GLP-1 and fasting GIP were significantly increased. DPP-4 activity had no relation to OSA parameters or severity, while body mass index was significantly higher in those with severe OSA. Although significant changes in incretin secretion were not seen for 3 months after onset of continuous positive airway pressure therapy, the fasting GLP-1 level in the treated patients with severe OSA decreased to the same level as in untreated patients with normal to moderately severe OSA.Conclusions: OSA is associated with elevated serum levels of the incretin hormones GLP-1 (fasting) and GIP (post-prandial) in patients without diabetes. A significant association between body mass index and DPP-4, which is said to exist in healthy persons, was not found in the patients with OSA. Fasting GLP-1 in patients without diabetes with OSA may influence fasting glucose levels. [ABSTRACT FROM AUTHOR]

Rationale: Microalbuminuria is said to reflect systemic vascular damage and endothelial dysfunction and is an established indicator of cardiovascular morbidity and mortality. Patients with obstructive sleep apnea (OSA)-chronic obstructive pulmonary disease (COPD) overlap syndrome have worse survival than those with OSA or COPD alone.Objectives: This study evaluated the association between overlap syndrome and microalbuminuria.Methods: Data on patients in whom OSA was suspected and who underwent polysomnography between January 2010 and December 2012 were reviewed. Microalbuminuria was defined as an albumin-creatinine ratio between 20 and 299 mg/g in men and between 30 and 299 mg/g in women.Measurements and Main Results: Of 740 consecutive patients, 344 were analyzed. Sixty-four were control participants, 248 had OSA only, 4 had COPD only, and 28 had OSA-COPD overlap syndrome. Prevalence of microalbuminuria significantly increased in the order of control, OSA, and overlap syndrome groups (3.1, 12.9, and 32.1%, respectively; P = 0.0006). After adjusting for age and sex, multivariate logistic regression analysis demonstrated a significant association of overlap syndrome with microalbuminuria compared with OSA (odds ratio, 2.61; 95% confidence interval, 1.02-6.38; P = 0.047), but after adjusting for other confounding factors, the difference in the association did not reach significance (odds ratio, 2.54; 95% confidence interval, 0.93-6.72; P = 0.070). Of 63 patients reevaluated after 3 months of continuous positive airway pressure therapy, the logarithm of the albumin-creatinine ratio in 36 patients with good compliance significantly decreased, but there was no difference in patients with poor compliance.Conclusions: OSA-COPD overlap syndrome was more prevalent than OSA alone in patients with microalbuminuria, but the difference might be mediated by conventional risk factors rather than the addition of COPD itself. [ABSTRACT FROM AUTHOR]