Non-obese Obstructive Sleep Apnea Patients Research Articles

Long-term incident hard outcomes in a prospective cohort of non-obese obstructive sleep apnoea patients free of comorbidities at inclusion

Long-term incident hard outcomes in a prospective cohort of non-obese obstructive sleep apnoea patients free of comorbidities at inclusion

P016 Effects of Aerobic Exercise versus Inspiratory Muscle training on Apnea-Hypopnea Index in patients with Obstructive Sleep Apnea

Abstract Introduction There is some evidence indicating that exercise, such as aerobic training (AT) and inspiratory muscle training (IMT), improves Obstructive Sleep Apnea (OSA) symptoms. Nonetheless, no study compares the types of exercise in OSA patients. Objective To compare the effects of type of exercise on Apnea-Hypopnea Index (AHI) and respiratory muscle strength in OSA patients Methods Twenty-nine non-obese OSA patients aged 20-50 years with mild to moderate severity (Apnea-hypopnea index 5-30 events/hour) were randomized to the AT group (n=9), the IMT group (n=10) or the control (CON) group (n=10). Participants in the AT group received 60 minutes per day, 3 times per week, for 12 weeks. For the IMT group, participants received the Powerbreathe ® device for practicing 8 cycles of 30 breaths per day, 5 times per week, for 12 weeks. Participants in the CON group did not receive any intervention. Their AHI and respiratory muscle strength were analyzed during the pre- and post-tests. Dependent variables were compared between pre- and post-tests via paired t-test, and independent variables were compared between the groups using one-way analysis of variance (ANOVA). Differences were considered significant at p<0.05. Results AHI, maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) changed significantly in the AT group and IMT group after 12 weeks of training. Therefore, AHI, MIP, and MEP in the AT group and the IMT group improved significantly compared to the CON group. Conclusions Aerobic training and inspiratory muscle training improve the apnea-hypopnea index and respiratory muscle strength in OSA patients.

Comorbidity Profile and Predictors of Obstructive Sleep Apnea Severity and Mortality in Non-Obese Obstructive Sleep Apnea Patients.

Backgrounds and Objectives: Obstructive sleep apnea (OSA) is associated with increased morbidity and mortality. OSA is an independent risk factor for many different conditions, especially cardiovascular diseases. The purpose of this study was to ascertain the comorbidity profile of non-obese patients with newly diagnosed OSA and evaluate the risk for cardiovascular disease and mortality. The present study also aimed to establish predictors for OSA severity. Materials and Methods: This study included 138 newly diagnosed patients who underwent polysomnographic analysis. The 10-year risk for cardiovascular disease was assessed using a newly validated prediction model: Systematic Coronary Risk Evaluation (SCORE-2). In addition, the Charlson Comorbidity Index (CCI) was assessed as a widely-used example of a mortality comorbidity index. Results: The study population included 138 patients: 86 males and 52 females. Patients were stratified, according to AHI (apnea/hypopnea index), into four groups: 33 patients had mild OSA (5 ≤ AHI < 15), 33 patients had moderate OSA (15 ≤ AHI < 30), 31 patients had severe OSA (AHI ≥ 30), and 41 individuals had AHI < 5, which were a part of the control group. SCORE-2 increased in line with OSA severity and was higher in OSA groups compared to the control group (H = 29.913; DF = 3; p < 0.001). Charlson Index was significantly higher in OSA patients compared to controls (p = 0.001), with a higher prevalence of total comorbidities in the OSA group of patients. Furthermore, CCI 10-year survival score was significantly lower in the OSA group, suggesting a shorter survival of those patients with a more severe form of OSA. We also examined the prediction model for OSA severity. Conclusions: Determining the comorbidity profile and estimation of the 10-year risk score of OSA patients could be used to classify these patients into various mortality risk categories and, according to that, provide them with adequate treatment.

Risk Factors of Nonalcoholic Fatty Liver Disease and Liver Fibrosis in Non-Obese Patients with Obstructive Sleep Apnea.

Liver injury in non-obese obstructive sleep apnea (OSA) patients has received much attention in recent years. This study aimed to investigate risk factors of nonalcoholic fatty liver disease (NAFLD) and liver fibrosis in non-obese patients with OSA. A retrospective study was conducted in the Sleep Center of the First Affiliated Hospital of Fujian Medical University. All consecutive non-obese patients with suspected sleep apnea admitted to the center were enrolled. The clinical characteristics of patients with simple snoring and with different severity OSA were compared. Multivariate logistic regression models were used to analyze the risk factors of NAFLD and liver fibrosis. A total of 410 patients were enrolled. The levels of triglyceride, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) increased with the aggravation of OSA (All p<0.05). Among non-obese patients with OSA, 17 (5%) were diagnosed with liver fibrosis and 228 (65%) with NAFLD; Apnea‑hyponea index (AHI) was an independent predictor for NAFLD and liver fibrosis [OR (95% CI): 1.02 (1.00-1.03), 1.04 (1.00-1.07), both p<0.05]; hypertriglyceridemia was an independent predictor for NAFLD [OR (95% CI): 1.13 (1.12-1.99), p<0.05]. NAFLD and liver fibrosis were common in non-obese OSA patients and the severity of OSA was an independent risk factor for them.

Waist-hip ratio is an independent predictor of moderate-to-severe OSA in nonobese males: a cross-sectional study

BackgroundAdiposity is a well-established risk factor for obstructive sleep apnea (OSA), but whether a combination of preferable anthropometric measurements may improve the accuracy of detecting OSA is unknown. This study aimed to explore the accuracies of the waist-hip ratio (WHR) in conjunction with the body mass index (BMI) when identifying the severity of OSA.DesignA total of 2012 participants in the China-Japan Friendship Hospital from January 2018 to December 2019 underwent anthropometric measurements and an overnight home sleep test (HST). The 244 subjects who met the criteria for obstructive sleep apnea (apnea–hypopnea index (AHI) ≥ 5 events/hour) were divided into four groups: Group A (55 patients with WHR ≥ 0.9 and BMI ≥ 28 kg/m2); Group B (12 patients with WHR < 0.9 and BMI ≥ 28 kg/m2); Group C (69 patients with WHR ≥ 0.9 and BMI < 28 kg/m2); and group D (108 patients with WHR < 0.9 and BMI < 28 kg/m2).ResultsThe AHI, apnea index (AI), hypopnea index (HI), and oxygen desaturation index (ODI) were significantly different among the 4 groups (p < 0.05). The WHR was positively correlated with AHI (r = 0.22, p < 0.001), AI (r = 0.270, p = 0.004), and ODI (r = 0.286, p = 0.0022) and negatively correlated with lowest oxygen pulse saturation (LSpO2) (r = 0.246, p = 0.008) only in nonobese patients. Moreover, the WHR was found to be a screening marker for moderate-to-severe OSA in Group D (p < 0.05). When used to identify severe OSA in Group D, the WHR cut-off point of 0.873 yielded a sensitivity of 65% and specificity of 56% (p < 0.05).ConclusionIn nonobese male OSA patients, WHR is a moderate screening marker for moderate-to-severe OSA and an independent risk factor for OSA severity.

Mini-implant assisted rapid palatal expansion (MARPE) effects on adult obstructive sleep apnea (OSA) and quality of life: a multi-center prospective controlled trial

IntroductionTransverse maxillary deficiency is a high prevalent growth disorder within the adult population that may lead to serious health issues, such as detrimental malocclusions and higher risk of developing obstructive sleep apnea (OSA). Mini-implant assisted rapid palatal expansion (MARPE), as it expands the mid-face and augment the nasal and oral cavities dimensions, may reduce the airflow resistance and thus play an important role on OSA therapy in some patients. The main objective of the present trial is to assess MARPE effects on the sleep and quality of life of non-obese adult OSA patients with transverse maxillary deficiency.MethodsA total of 32 participants were divided into intervention and control groups. They underwent physical evaluation, Epworth Sleepiness Scale (EES) and Quebec Sleep Questionnaire (QSQ), cone-beam computed tomography (CBCT) and home sleep testing (HST) for OSA before MARPE (T1) and 6 months after the intervention (T2).ResultsQuestionnaires EES (daytime sleepiness) and QSQ (OSA-related quality of life) presented significant statistical differences between the groups. We also found clinical and statistical (p < 0.01) differences between the groups regarding the apnea/hypopnea index (AHI), as well as others HST parameters (mean oxygen saturation and snoring duration).ConclusionIn our sample, MARPE (without any auxiliary osteotomy) showed a good success rate (85%) and promoted important occlusal and respiratory benefits. We observed important daytime sleepiness and OSA-related quality of life improvement, as well as the AHI (65.3%), oxygen saturation and snoring duration.

Comparison of clinical, biochemical, and polysomnographic parameters between obese and nonobese obstructive sleep apnea.

Background:Obstructive sleep apnea (OSA) occurs in both obese and nonobese individuals. This study was designed to compare clinical, metabolic profile, and polysomnographic parameters among obese and nonobese OSA patients.Material and Methods:This cross-sectional retro-prospective study involved 148 OSA patients. OSA patients were classified as nonobese (body mass index [BMI] <27.5 kg/m2) and obese (BMI ≥27.5 kg/m2) to determine the influence of BMI on its risks, clinical, metabolic, and polysomnographic parameters. For statistical comparisons, continuous variables were analyzed by Student’s t-test and categorical variables by Chi-square.Results:Of 148 patients, 106 patients were of a retrospective group and 42 in the prospective group. 116 patients were obese and 32 were nonobese with a mean BMI of 33.66 ± 5.3 versus. 25.17 ± 2.2 kg/m2 respectively. Female sex (70.7% vs. 43.4%), larger neck circumference (37.99 ± 3.93 vs. 33.67 ± 5.5 cm), loud snoring (94.8% vs. 81.3%), excessive daytime sleepiness (53.4% vs. 9.4%), fatigability (94.8% vs. 75%), high Epworth Sleepiness Scale score (16% vs. 8%), and hypertension (77.6% vs. 46.9%) were significantly (P < 0.05) more common among obese OSA patients while as smoking and sedative use was more prevalent among nonobese OSA group. However, no significant difference in median apnea-hypopnea index and severity of OSA between obese and nonobese group was observed. At the same time, the median oxygen desaturation index was significantly higher in obese patients (26.1 vs. 12.7, P = 0.005).Conclusion:Nonobese OSA patients depicted less severe disease symptoms and thus require high index of suspicion for early identification due to associated cardiovascular risk.

Clinical and Polysomnographic Characteristics of Nonobese and Obese Chinese Patients With Obstructive Sleep Apnea.

Obesity is a risk factor associated with the onset and exacerbation of obstructive sleep apnea (OSA). However, the majority of OSA patients in Asian populations are nonobese. To date, there have been insufficient large-scale studies of the differences in the clinical and polysomnographic features of obese and nonobese OSA patients in this population, and few studies have sought to identify predictors of OSA severity in affected obese and nonobese patients. We conducted a case-matched retrospective study, including 652 consecutive Chinese OSA patients (326 nonobese and 326 obese) to assess differences in demographic, clinical, and polysomnographic data between these two groups. Independent predictors of OSA severity were identified through multivariate linear regression analysis. The age and gender distributions of our obese and nonobese OSA patient cohorts did not differ significantly ( P > 0.05), and rates of comorbidities were comparable in these two patient groups ( P > 0.05). Nonobese patients were more likely to report atypical symptoms of OSA, including insomnia ( P < 0.001), irritability ( P < 0.05), and depressive symptoms ( P < 0.01), whereas obese patients were more likely to report typical symptoms of OSA, such as habitual snoring ( P < 0.001), witnessed apnea ( P < 0.05), and daytime sleepiness ( P < 0.001). Relative to nonobese patients, those who were obese exhibited significantly higher apnea-hypopnea index during total sleep time ( P < 0.001), apnea-hypopnea index during nonrapid eye movement sleep ( P < 0.001), and apnea-hypopnea index during rapid eye movement sleep ( P < 0.001), in addition to lower average oxygen saturation ( P < 0.001), minimal oxygen saturation ( P < 0.001), and a higher oxygen desaturation index ( P < 0.001) and arousal index ( P < 0.001). Total sleep time was, on average, shorter for nonobese patients ( P < 0.05), who also exhibited decreased sleep efficiency and more frequent awakening relative to obese patients ( P < 0.05). A multivariate linear regression analysis revealed that neck circumference and waist circumference were independent predictors of OSA severity in obese patients ( P < 0.05). On average, OSA was typically less severe in nonobese patients, who were also more likely to experience atypical OSA symptoms relative to obese patients. These results also suggest that the differential contributions of body fat accumulation and distribution to OSA severity may offer insights into the pathogenesis, clinical manifestations, and optimal management of this condition in nonobese and obese patient populations. It is vital that clinicians consider these differences to properly diagnose and treat this debilitating condition.

Obesity attenuates the effect of sleep apnea on active TGF-\xdf1 levels and tumor aggressiveness in patients with melanoma

Active transforming growth factor-β1 (TGF-β1), a cytokine partially regulated by hypoxia and obesity, has been related with poor prognosis in several tumors. We determine whether obstructive sleep apnea (OSA) increases serum levels of active TGF-β1 in patients with cutaneous melanoma (CM), assess their relationship with melanoma aggressiveness and analyze the factors related to TGF-β1 levels in obese and non-obese OSA patients. In a multicenter observational study, 290 patients with CM were underwent sleep studies. TGF-β1 was increased in moderate-severe OSA patients vs. non-OSA or mild OSA patients with CM. In OSA patients, TGF-β1 levels correlated with mitotic index, Breslow index and melanoma growth rate, and were increased in presence of ulceration or higher Clark levels. In CM patients, OSA was associated with higher TGF-β1 levels and greater melanoma aggressiveness only in non-obese subjects. An in vitro model showed that IH-induced increases of TGF-β1 expression in melanoma cells is attenuated in the presence of high leptin levels. In conclusion, TGF-β1 levels are associated with melanoma aggressiveness in CM patients and increased in moderate-severe OSA. Moreover, in non-obese patients with OSA, TGF-β1 levels correlate with OSA severity and leptin levels, whereas only associate with leptin levels in obese OSA patients.

The impact of obesity in cognitive and memory dysfunction in obstructive sleep apnea syndrome.

Obstructive sleep apnea (OSA), a sleep disorder, results in decreased daytime alertness and neurocognitive dysfunction. Obesity is considered a major risk factor for the development and progression of OSA and the resulting cognitive dysfunction. However, the effect of obesity on neurocognitive dysfunction in OSA has been rarely investigated. Eighty-three patients with moderate to severe OSA syndrome were recruited in our study. After matching for education, age, and body mass index (BMI), 40 patients were enrolled into our study with matched obese (BMI ≧ 30) and non-obese (BMI < 30) groups. All enrolled patients completed a polysomnographic study, sleepiness questionnaires, and attention, cognitive, and memory function tests. Compared to obese OSA patients, non-obese OSA patients had shorter reaction times in the psychomotor vigilance task but not the Flanker or Stroop cognitive tasks. Additionally, obese OSA patients had a reduced capacity for working memory relative to non-obese OSA patients. Obesity had a significant effect on OSA patients in our study, including delayed reaction times in the psychomotor vigilance task and a decrease in working memory.

Association of epicardial fat thickness with clinical and polysomnographic parameters in non-obese obstructive sleep apnoea patients.

This study aimed to investigate the relationship of epicardial fat thickness with severity of obstructive sleep apnoea, and clinical and polysomnographic parameters, and to determine independent predictors for epicardial fat thickness. A total of 84 patients with a body mass index of less than 30 kg/m2 and suspected sleep-disordered breathing were included in the study. The correlations of epicardial fat thickness with polysomnographic and clinical data, and severity of obstructive sleep apnoea, were investigated. Mean epicardial fat thickness was 3.75 ± 1.07 mm in the study group (n = 62) and 2.97 ± 0.62 mm in the control group (n = 22) (p < 0.001). There were significant positive correlations between epicardial fat thickness and: apnoea/hypopnoea index, oxygen desaturation index 3 and minimum oxygen saturation, as well as with age, body mass index, and neck and waist circumferences. Non-obese obstructive sleep apnoea patients have thicker epicardial fat compared to controls. Oxygen desaturation index 3 has a strong correlation with epicardial fat thickness and is an independent predictor of it.

The serum leptin level in non-obese patients with obstructive sleep apnea

ObjectiveThis study aimed to determine the association between the severity of obstructive sleep apnea (OSA) and the serum leptin level in non-obese OSA patients. MethodsThis prospective case-control study included non-obese OSA patients that presented with sleep-related disturbances and underwent polysomnography (PSG) between April 2015 and June 2016. The serum leptin level was measured and its relationship to PSG parameters was investigated. ResultsThe study included 73 OSA patients (20 female and 53 male) with a mean age of 41.1±11.5 years and mean body-mass index (BMI) of 26.4±2.7kgm–2. The serum leptin level in 44 patients with moderate/severe OSA (AHI ≥15) was 3.4±2.6ngmL–1, versus 4.5±3.8ngmL–1 in 29 patients with snoring/mild OSA (AHI <15) (P=0.20). There were not any correlations between any of the PSG parameters and the serum leptin level, but there was a significant correlation between the leptin level and BMI (r=0.345, P<0.01). ConclusionThe serum leptin level does not differ significantly between non-obese OSA patients with moderate/severe and snoring/mild OSA. Obesity is the primary factor associated with the serum leptin level.

Location of the narrowest area of the pharynx regarding body mass index and obstructive sleep apnoea severity.

Among authors studying morphological determinants of the obstructive sleep apnoea (OSA) controversies exist on the location of the narrowest area within the pharynx, critical for development of obstruction. Those disagreements primarily revolve around differences between obese and nonobese OSA patients. Determination whether the location and size of the narrowest area within the pharynx differentiates the obese and nonobese OSA patients. A population of 55 subjects was investigated after being diagnosed with OSA in the Polysomnography Laboratory of the Department and Clinic of Otolaryngology in the Medical University of Warsaw, Poland. Additionally a head computed tomography (CT) was performed in all the subjects. The CT images were used to do several crucial measurements which described the geometry of the facial skeleton as well as soft tissues of the head. The obtained results were correlated with apnoea-hypopnoea index (AHI) and body mass index (BMI) values. The data were statistically analysed. The distance between the hard palate and posterior pharyngeal wall parallel to the horizontal plane as well as the shortest distance between the soft palate and posterior pharyngeal wall significantly differentiated patients in the subgroups by AHI but not by BMI. Pharyngeal obstruction at the level of the hard and soft palate differentiates patients with severe OSA from patients with mild and moderate OSA regardless of BMI.

Impaired control of gait in patients with severe obstructive sleep apnea is reversed by continuous positive airway pressure treatment

Obstructive sleep apnea (OSA) is now widely seen as a major public health issue with widespread societal consequences. In addition to an increased stroke risk, OSA leads to cerebral consequences including cognitive deficits that impair quality of life and daily functioning. In a recent uncontrolled study, moderate-to-severe OSA have been associated with higher stride time variability (STV), reflecting poor gait control (Celle, Annweiler et al., 2014). STV is a clinical marker of cortical gait control linked with cognitive performance and cerebral integrity (Beauchet, Annweiler et al., 2014). Whether continuous positive airway pressure (CPAP), the most effective and widely used treatment in OSA, could improve gait impairments remains to be investigated. This study aims to evaluate the impact of an 8-week CPAP treatment on gait performance evaluated by STV in OSA patients. Twelve non-obese, severe OSA patients (age = 57.2 ± 8.9 years, BMI = 27.4 ± 3.1 kg·m−2, AHI = 46.3 ± 11.7) and 10 healthy matched subjects were included for comparison. In this prospective controlled study, gait was assessed overground, at spontaneous speed, using a 10-meter Optogait walkway. Gait spatio-temporal parameters were recorded and STV was calculated. The role of cognition in gait control was investigated using a dual-task paradigm. Spatiotemporal gait parameters were recorded at preferred speed on a treadmill in single and in dual task condition, using a Stroop interference task. Cognitive performance at Stroop test was assessed at rest (single task) and while walking (dual task) by calculating the correct response rate. All the assessments were performed before and after 8 weeks of CPAP treatment. At baseline, OSA patients showed higher STV (3.1 ± 1.1% vs 2.1 ± 0.5%, P = 0.02) and step width (16.1 ± 2.9 cm vs 12.3 ± 1.3 cm, P = 0.001) as compared to controls. They also showed a lower rate of correct responses at the Stroop test when walking (66.5 ± 9.3 vs 90.5 ± 10.9, P < 0.001). After CPAP treatment, both spatiotemporal gait parameters (post-CPAP STV: 2.4 ± 0.5%, P = 0.005 vs baseline) and cognitive performances when walking (post-CPAP correct response rate 74.4 ± 13.04, P = 0.016 vs baseline) were improved in OSA patients and did not differ anymore from controls. Severe non-obese OSA patients have an impaired gait control, which may be reversed after 8 weeks of CPAP treatment. Our data suggest its cognitive origin.

Glucose tolerance and cardiovascular risk biomarkers in non-diabetic non-obese obstructive sleep apnea patients: Effects of long-term continuous positive airway pressure

BackgroundInsulin resistance, glucose dyshomeostasis and oxidative stress are associated to the cardiovascular consequences of obstructive sleep apnea (OSA). The effects of a long-term continuous positive airway pressure (LT-CPAP) treatment on such mechanisms still remain conflicting. ObjectiveTo investigate the effect of LT-CPAP on glucose tolerance, insulin sensitivity, oxidative stress and cardiovascular biomarkers in non-obese non-diabetic OSA patients. Patients & methodsTwenty-eight apneic, otherwise healthy, men suffering from OSA (mean age = 48.9 ± 9.4 years; apnea-hypopnea index = 41.1 ± 16.1 events/h; BMI = 26.6 ± 2.8 kg/m2; fasting glucose = 4.98 ± 0.37 mmol/L) were evaluated before and after LT-CPAP by an oral glucose tolerance test (OGTT), measuring plasma glucose, insulin and proinsulin. Glycated hemoglobin, homeostasis model assessment resistance insulin, blood lipids, oxidative stress, homocysteine and NT-pro-brain natriuretic peptide (NT-proBNP) were also measured. ResultsLT-CPAP treatment lasted 13.9 ± 6.5 months. At baseline, the time spent at SaO2<90%, minimal and mean SaO2 were associated with insulin area under the curve during OGTT (r = 0.448, P = 0.011; r = −0.382; P = 0.047 and r = −0.424; P = 0.028, respectively) and most other glucose/insulin homeostasis biomarkers, as well as with homocysteine (r = 0.531, P = 0.006; r = −0.487; P = 0.011 and r = −0.409; P = 0.034, respectively). LT-CPAP had no effect on all the OGTT-related measurements, but increased plasma total antioxidant status (+7.74%; P = 0.035) in a duration-dependent manner (r = 0.607; P < 0.001), and decreased both homocysteine (−15.2%; P = 0.002) and NT-proBNP levels (−39.3%; P = 0.002). ConclusionsIn non-obese non-diabetic OSA patients, nocturnal oxygen desaturation is strongly associated to insulin resistance. LT-CPAP does not improve glucose homeostasis nor insulin sensitivity but has a favorable effect on antioxidant capacity and cardiovascular risk biomarkers.

Echocardiographic findings and plasma endothelin-1 levels in obese patients with and without obstructive sleep apnea.

Obstructive sleep apnea (OSA) and obesity are increasingly prevalent worldwide. Both promote endothelial dysfunction contributing to systemic and pulmonary hypertension over time. Endothelin-1 (ET-1) plays a pivotal role in the development of pulmonary hypertension (PH). The aim of the present study was to assess the association between plasma ET-1 and echocardiographic findings in obese individuals with and without OSA, as well as in non-obese patients with OSA. Ninety-seven subjects (56 males) were enrolled in the study. All subjects underwent the following tests: venous endothelin-1 levels, pulmonary function testing, and arterial blood gas analysis. All patients except controls underwent transthoracic echocardiography and portable testing for sleep-disordered breathing. Plasma ET-1 levels were significantly higher in obese patients, both with and without OSA (respectively, n = 30 (mean value, 268.06 ± 49.56pg/ml) and n = 32 (mean value, 263.12 ± 65.26pg/ml)), compared with non-obese patients with OSA or to healthy controls (respectively, n = 20 (mean value, 149.8 ± 23.09pg/ml) and n = 15 (mean value, 152.3 ± 27.64pg/ml); p < 0.0001). Pulmonary artery pressure (PAPs) in obese patients with OSA were significantly higher than in obese patients without OSA (p < 0.0001), while there was no statistical difference between PAPs of obese patients without OSA, compared with the group of non-obese OSA patients. Plasma ET-1 levels significantly correlated with systolic PAPs in obese patients both with and without OSA (respectively, n = 30, r = 0.385, p = 0.03567; n = 32, r = 0.3497, p = 0.0497). Our study suggests that endothelin levels are more strongly associated with weight than the presence of sleep-disordered breathing, but pulmonary artery hypertension is associated with both weight and OSA.

Comparison of Polysomnographic and Clinical Presentations and Predictors for Cardiovascular-Related Diseases between Non-Obese and Obese Obstructive Sleep Apnea among Asians

Unlike Caucasians, many Asians with obstructive sleep apnea (OSA) are non-obese but are affected by the disease due to predisposing craniofacial structure. Therefore, non-obese and obese OSA may represent different disease entities. The associated risk factors for developing cardiovascular-related diseases, consequently, may be considered separately for the two types of OSA. We reviewed polysomnographic studies performed in adults (aged ≥ 18 years) diagnosed with OSA (respiratory disturbance index [RDI] ≥ 5). We divided the patients into obese (body mass index [BMI] ≥ 25) and non-obese (BMI < 25) groups. We aimed to determine the differences between these two groups in terms of clinical presentations, polysomno-graphic findings, and association with cardiovascular-related diseases including hypertension, diabetes mellitus, coronary artery disease, and/or cerebrovascular disease. Among 194 patients with OSA (RDI ≥ 5), 63.4% were non-obese and 36.6% were obese. Compared with obese OSA patients, non-obese OSA patients were noted to have smaller neck size, less prevalence of hypertension, and less history of frequent nocturia (> 3-4/week), with equal prevalence of excessive daytime sleepiness. Overall, non-obese OSA patients were noted to have milder disease indicated by lower total, supine, and non-supine, NREM RDI and higher mean and nadir oxygen saturations. In the non-obese group, only total obstructive apnea index (OAI) was noted to be a predictor for developing any of the cardiovascular-related diseases after controlling for age, sex, and RDI (odds ratio = 9.7). However, in the obese OSA group, frequent snoring (> 50% of total sleep time), low sleep efficiency (≤ 90%), and low mean oxygen saturation (< 95%) were noted to be significant predictors of cardiovascular-related diseases (odds ratios = 12.3, 4.2, and 5.2, respectively). Among Asians, most OSA patients were not obese. Compared to obese OSA patients, non-obese OSA patients were noted to have less prevalence of hypertension and less history of nocturia. They were also noted to have overall milder OSA. Only OAI was noted to be a significant predictor for cardiovascular-related disease in the non-obese OSA group.

Difference in dental arch size between obese and non‐obese patients with obstructive sleep apnoea

A large tongue is recognised as a factor that increases the collapsibility of the upper airway in obstructive sleep apnoea (OSA) patients. We hypothesised that the propensity to develop severe OSA could be minimised if the dental arches were enlarged in obese OSA people who are thought to have a large tongue. We therefore compared the size of the dental arches in obese and non-obese OSA patients. Using a lateral cephalogram and study models, we compared the sizes of the tongue and dental arches in 23 obese and 23 non-obese Japanese male OSA patients, who were matched for age, apnoea hypopnea index (AHI) and maxillomandibular size. The median age (years) and AHI (events per hour) for the obese and non-obese groups were 36·5 and 39·0, and 13·4 and 14·3, respectively. The maxillomandibular size was matched with regard to SNA, SNB and lower face cage obtained from cephalometric measurements. The parameters that were measured for the study model included dental arch width, dental arch length, overjet and overbite. Tongue size (P < 0·05) and both upper (P < 0·01) and lower (P < 0·05) dental arch widths were significantly larger in obese than in non-obese OSA patients, and there was no difference in the severity of OSA between the two groups. These findings suggest that the tongue was larger and dental arches were enlarged in obese patients compared with non-obese patients under the same disease severity. Wider dental arches in obese OSA patients may help to offset the impact of the enlarged tongue on upper airway patency.

Association of urinary 15-F 2t-isoprostane level with oxygen desaturation and carotid intima–media thickness in nonobese sleep apnea patients

Obstructive sleep apnea (OSA) is characterized by recurrent apnea during sleep that may unbalance oxidative stress, increasing atherosclerosis. Among oxidative stress markers, 15-F 2t-isoprostane is considered one of the most sensitive and specific metabolites of lipid peroxidation. To explore the relationship between urinary 15-F 2t-isoprostane with sleep apnea severity and carotid modifications in nonobese OSA patients, 31 nonobese sleep apnea patients were studied, along with 10 lean subjects without OSA. Patients were assessed by polysomnography, blood pressure measurement, and ultrasonography to determine the carotid intima–media thickness (IMT). Urinary 15-F 2t-isoprostanes were measured by liquid chromatography–tandem mass spectrometry. Urinary 15-F 2t-isoprostane concentrations were increased in severe OSA patients compared to control subjects (20.2 ± 7.3 vs 12.3 ± 2.8 ng/mmol creatinine; P = 0.020). Mean carotid IMT was correlated with 15-F 2t-isoprostane ( r = 0.532; P < 0.001) and with the apnea–hypopnea index ( r = 0.345; P = 0.029). 15-F 2t-Isoprostane level was related to the night time spent at SaO 2 < 90% ( r = 0.478; P = 0.002), the apnea–hypopnea index ( r = 0.465; P = 0.003), and the mean nocturnal SaO 2 ( r = − 0.424; P = 0.007). These results showed a relationship between lipid peroxidation, carotid intima–media thickness, and intermittent hypoxia in nonobese OSA patients, thus reinforcing the hypothesis that oxidative stress could be involved in the early atherosclerotic process.

Systemic and airway inflammation in sleep apnea and obesity: the role of ICAM-1 and IL-8

The recurrent hypoxic stress that characterizes obstructive sleep apnea (OSA) seems to play a role in the increased adherence of neutrophils to endothelial cells as well as in the resulting migration of the former to the inflamed area. Intercellular adhesion molecule 1 (ICAM-1) and interleukin (IL)-8 are markers widely used in OSA studies to investigate inflammation. The aim of this study was to measure ICAM-1 and IL-8 levels in the breath condensate and in the plasma and inflammatory cells in the induced sputum of 12 obese OSA (OO) patients, 10 nonobese OSA (NOO) patients, 10 obese non-OSA (ONO) subjects, and 8 healthy subjects (HS) using a specific enzyme immunoassay (EIA) kit. A significant increase in both plasma and exhaled IL-8 and ICAM concentrations and percentage neutrophils was observed in the induced sputum of obese OSA patients, non-obese OSA patients, and obese non-OSA subjects compared with healthy subjects. However, although these inflammatory markers were found to follow an upward trend in obese OSA patients no difference was observed in both either non-obese OSA patients and obese non-OSA subjects. Finally, a significant positive correlation was found to occur among IL-8, ICAM-1, and sputum neutrophils, as well as across the apnea-hypopnoea index (AHI), TST 90%, body mass index (BMI), and neck circumference. The data obtained confirm the occurrence of an ICAM- and IL-8-mediated neutrophilic airway inflammation in both OSA and obese patients. The degree of inflammation, which seems to worsen in cases of comorbidity (OSA and obesity), is likely to be responsible for the increased risk of developing cardiovascular events observed in these subjects, and therefore, it deserves to be elucidated even more.