Associations between Vitamin D Status and Polysomnographic Parameters in Adults with Obstructive Sleep Apnea.

Vitamin D deficiency (VDD) may be associated with obstructive sleep apnea (OSA) presence and is more pronounced with increasing OSA severity; however, the relationship between these two entities remains unclear. This was a cross-sectional study among 262 adults with in-hospital-attended polysomnography-diagnosed OSA and no additional major comorbidities, aiming to explore possible associations between serum 25-hydroxyvitamin D [25(OH)D] levels and polysomnographic parameters. Data on demographics, medical history, anthropometric indices, and lifestyle habits were collected at enrolment. Serum 25(OH)D was evaluated using chemiluminescence, with VDD defined as 25(OH)D < 20 ng/mL. VDD was observed in 63% of the participants. Serum 25(OH)D correlated negatively with apnea-hypopnea index and other polysomnographic indices (all p < 0.05). In logistic regression analysis, adjusting for age, sex, smoking, body mass index, physical activity, dietary vitamin D intake, and season of blood sampling, serum 25(OH)D was associated with lower odds of severe OSA [odds ratio (95% confidence interval): 0.94 (0.90-0.98)]. In the same multivariate model, VDD was associated with ~threefold higher odds of severe OSA [2.75 (1.38-5.48)]. In stratified analyses, VDD predicted OSA severity in the group of participants ≥50 y [3.54 (1.29-9.68)] and among those with body mass index ≥ 30 kg/m2 [3.38 (1.52-7.52)], but not in the younger and non-obese adults. This study provides further evidence of an inverse association between vitamin D levels and OSA severity and underscores the importance of considering vitamin D status as a potential modifiable factor in the comprehensive management of OSA.

Sleep disorders during pregnancy: an underestimated risk factor for gestational diabetes mellitus.

Sleep disorders are highly prevalent during pregnancy and significantly affect women's health and quality of life. Gestational diabetes mellitus (GDM) is one of the most common metabolic complications during pregnancy and constitutes a significant risk factor for both mother and fetus in the short and the long term. While the association between sleep disorders and type 2 diabetes mellitus (T2DM) is indisputable, it is not clear whether there is a link between sleep disorders and GDM. The aim of this article was to investigate the association between sleep disorders and GDM and whether the treatment of sleep disorders may prevent GDM development. Insomnia, obstructive sleep apnea (OSA), restless legs syndrome (RLS), and narcolepsy were the most common sleep disorders identified during pregnancy and were related to poor sleep quality and short or prolonged sleep duration. They were all associated with an increased risk of GDM. The ideal sleep duration for pregnant women was determined at 8-9 h daily. In conclusion, sleep disorders constitute a risk factor for GDM. It is imperative that prospective studies be conducted to evaluate the effect of the early management of sleep disorders on GDM manifestation and control. Healthcare providers should highlight the importance of sufficient sleep to reinforce pregnancy outcomes.

Adherence to a "Western-type" dietary pattern is positively associated with the Apnea-Hypopnea Index in adults with obstructive sleep apnea.

Dietary habits have been associated with obstructive sleep apnea (OSA); however, the underlying mechanisms remain unclear. We hypothesized that adherence to dietary patterns may be associated with Apnea-Hypopnea Index (AHI) and OSA severity and that insulin resistance, oxidative stress, and inflammation may act as potential mediators of these associations. This was a cross-sectional study among 269 adult participants with polysomnography-diagnosed moderate-to-severe OSA. Dietary and physical activity habits were assessed through validated questionnaires, and biochemical, inflammatory, and oxidative stress markers were measured for all volunteers. Dietary patterns were identified using principal component analysis, and mediation analyses was also performed. A "Western-type" dietary pattern (characterized by high intakes of full-fat dairy, refined grains, potatoes, red meat, sweets, salty snacks, and soft drinks and low intakes of low-fat dairy and whole grains) was positively associated with AHI. Mediation analyses also revealed that insulin resistance partially explained this association. In multivariable models controlling for age, sex, smoking, socioeconomic status, obesity presence, energy intake, and physical activity level, participants in the highest quartile of adherence to the Western-type dietary pattern had ∼3.5 times higher likelihood of suffering from severe OSA, compared with participants in the lowest quartile of adherence (odds ratio [95% confidence interval]: 3.45 [1.21-9.94], P trend across quartiles: 0.024). After further adjustment for Homeostasis Model of Assessment-Insulin Resistance and high-sensitivity C-reactive protein, this association lost significance. Higher adherence to a less healthy, Western-type dietary pattern is positively associated with AHI and OSA severity, which may partially be mediated through insulin resistance.

Associations between serum vitamin D status and the cardiometabolic profile of patients with obstructive sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) and the metabolic syndrome (MetS) frequently coexist. Low serum vitamin D has been positively associated with OSA presence and severity; however, data on its link to cardiometabolic features in patients with OSA remain scarce. We aimed to assess serum 25-hydroxyvitamin D [25(OH)D] and explore its association with cardiometabolic parameters in OSA. METHODS: This was a cross-sectional study among 262 patients (49 ± 9 years old, 73% men) with polysomnography-diagnosed OSA. Participants were evaluated in terms of anthropometric indices, lifestyle habits, blood pressure, biochemical, plasma inflammatory and urinary oxidative stress markers, and the presence of MetS. Serum 25(OH)D was assessed by chemiluminescence, and vitamin D deficiency (VDD) was defined as 25(OH)D < 20 ng/mL. RESULTS: Median (1st, 3rd quartile) serum 25(OH)D levels were 17.7 (13.4, 22.9) ng/mL and 63% of participants had VDD. Serum 25(OH)D correlated negatively with body mass index (BMI), homeostasis model of assessment of insulin resistance (HOMA-IR), total cholesterol, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein (hsCRP), and urinary oxidized guanine species (oxG), and positively with high-density lipoprotein cholesterol (all P < 0.050). In logistic regression analysis, serum 25(OH)D was associated with lower odds of MetS [odds ratio (95% confidence interval): 0.94 (0.90-0.98)], after adjustment for age, sex, season of blood sampling, Mediterranean diet score, physical activity, smoking, apnea-hypopnea index, HOMA-IR, hsCRP, and oxG. In the same multivariate model, VDD was associated with ~ twofold greater odds of MetS [2.39 (1.15, 4.97)]. CONCLUSION: VDD is highly prevalent and is associated with a detrimental cardiometabolic profile among patients with OSA.

Association of sleep duration and quality with immunological response after vaccination against severe acute respiratory syndrome coronavirus-2 infection.

Growing evidence suggests that sleep could affect the immunological response after vaccination. The aim of this prospective study was to investigate possible associations between regular sleep disruption and immunity response after vaccination against coronavirus disease 2019 (COVID-19). In total, 592 healthcare workers, with no previous history of COVID-19, from eight major Greek hospitals were enrolled in this study. All subjects underwent two Pfizer-BioNTech messenger ribonucleic acid (mRNA) COVID-19 vaccine BNT162b2 inoculations with an interval of 21 days between the doses. Furthermore, a questionnaire was completed 2 days after each vaccination and clinical characteristics, demographics, sleep duration, and habits were recorded. Blood samples were collected and anti-spike immunoglobulin G antibodies were measured at 20 ± 1 days after the first dose and 21 ± 2 days after the second dose. A total of 544 subjects (30% males), with median (interquartile range [IQR]) age of 46 (38-54) years and body mass index of 24·84 (22.6-28.51) kg/m2 were eligible for the study. The median (IQR) habitual duration of sleep was 6 (6-7) h/night. In all, 283 participants (52%) had a short daytime nap. In 214 (39.3%) participants the Pittsburgh Sleep Quality Index score was >5, with a higher percentage in women (74·3%, p < 0.05). Antibody levels were associated with age (r = -0.178, p < 0.001), poor sleep quality (r = -0.094, p < 0.05), insomnia (r = -0.098, p < 0.05), and nap frequency per week (r = -0.098, p < 0.05), but after adjusting for confounders, only insomnia, gender, and age were independent determinants of antibody levels. It is important to emphasise that insomnia is associated with lower antibody levels against COVID-19 after vaccination.

Improvements in Plasma Tumor Necrosis Factor-Alpha Levels after a Weight-Loss Lifestyle Intervention in Patients with Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) and systemic inflammation typically coexist within a vicious cycle. This study aimed at exploring the effectiveness of a weight-loss lifestyle intervention in reducing plasma tumor necrosis factor-alpha (TNF-a), a well-established modulator of systematic inflammation in OSA. Eighty-four adult, overweight patients with a diagnosis of moderate-to-severe OSA were randomized to a standard care (SCG, n = 42) or a Mediterranean lifestyle group (MLG, n = 42). Both groups were prescribed continuous positive airway pressure (CPAP), while the MLG additionally participated in a 6-month behavioral intervention aiming at healthier weight and lifestyle habits according to the Mediterranean pattern. Plasma TNF-a was measured by an immunoenzymatic method both pre- and post-intervention. Drop-out rates were 33% (n = 14) for the SCG and 24% (n = 10) for the MLG. Intention-to-treat analysis (n = 84) revealed a significant decrease in median TNF-a only in the MLG (from 2.92 to 2.00 pg/mL, p = 0.001). Compared to the SCG, the MLG exhibited lower follow-up TNF-a levels (mean difference adjusted for age, sex, baseline TNF-a and CPAP use: -0.97 pg/mL, p = 0.014), and further controlling for weight loss did not attenuate this difference (p = 0.020). Per protocol analyses (n = 60) revealed similar results. In conclusion, a healthy lifestyle intervention can lower plasma TNF-a levels in patients with OSA.

Impaired Human Sexual and Erectile Function Affecting Semen Quality, in Obstructive Sleep Apnea: A Pilot Study.

Obstructive sleep apnea (OSA) is a rising problem, with important implications for public health. Recent evidence has revealed a link between OSA and reduced male fertility. We investigated the association between OSA and sexual and erectile function, as well as semen quality, and the effect of treatment by continuous positive airway pressure (CPAP). A total of 41 male subjects, who underwent polysomnography for suspected OSA, participated in the study. Erectile and sexual function were assessed with the 15-item International Index of Erectile Function (IIEF-15) questionnaire, blood samples, and sperm analysis. OSA patients after the initiation of CPAP treatment were followed for a period of 1 year. Thirty-two patients were diagnosed with OSA, and nine subjects without OSA were used as a control group. OSA patients demonstrated significantly impaired erectile function, reduced testosterone levels, and lower semen quality. Multivariable regression analysis showed that BMI and IIEF score were independent determinants of AHI. Sexual function improved after a year of CPAP therapy in OSA patients. This study provides further evidence regarding the association between OSA and erectile function impairment, as well as semen quality. Longitudinal adherence to CPAP treatment has a beneficial effect on erectile function.

Association of adherence to the Mediterranean diet and physical activity habits with the presence of insomnia in patients with obstructive sleep apnea.

PURPOSE: Insomnia and obstructive sleep apnea (OSA) are among the most prevalent sleep disorders and frequently co-occur, defining the sleep apnea-insomnia syndrome. However, data exploring associations between insomnia and lifestyle habits in patients with OSA are lacking. Therefore, the aim of the present study was to investigate potential associations between insomnia presence and individual lifestyle parameters in patients with mild/moderate-to-severe OSA evaluated by attended polysomnography. METHODS: These are secondary analyses, using data from a cross-sectional study among 269 Greek patients with OSA. Clinical, anthropometric, socioeconomic, and lifestyle data were collected for all participants. Insomnia presence was evaluated through the validated psychometric instrument "Athens Insomnia Scale" (AIS). Adherence to the Mediterranean diet was estimated with the MedDietScale index and physical activity habits were assessed through a validated questionnaire. Backward stepwise multiple logistic regression analysis was used to estimate the association between lifestyle habits (i.e., adherence to the Mediterranean diet and physical activity) and the likelihood of having insomnia, while adjusting for potential confounders. RESULTS: Of 269 patients newly diagnosed with OSA (aged 21-70 years; 73% men), 146 (54%) were categorized as having insomnia. In multivariable models, higher adherence to the Mediterranean diet and engagement in physical activity for ≥ 30 min/day were both associated with a lower likelihood of having insomnia (odds ratio (95% confidence intervals): 0.40 (0.18-0.91) and 0.49 (0.28-0.86), respectively). CONCLUSIONS: Results add to the limited data on the role of lifestyle in insomnia and should be further explored both in epidemiological and clinical studies.

Higher refined cereal grain intake is positively associated with apnoea-hypopnoea index in patients with obstructive sleep apnoea.

BACKGROUND: Given that obesity is a well-known risk factor for obstructive sleep apnoea (OSA) development, dietary habits may be involved in its pathogenesis. However, little is known about the associations between dietary habits and OSA severity. The present study aimed to investigate possible associations between cereal grain intake and apnoea/hypopnoea indices in OSA patients. METHODS: This was a cross-sectional study of 269 patients (21-70 years; 73.2% males) diagnosed with OSA via an attended in-hospital polysomnography. Information on demographics, medical history, anthropometric indices and lifestyle habits were collected at enrolment. Biochemical measurements were performed in all study participants using standard procedures. Cereal grain consumption was evaluated using a validated food frequency questionnaire. Severe OSA was defined as having an apnoea-hypopnoea index ≥30 events h-1 . RESULTS: In adjusted analyses, higher intake of refined cereal grains was positively associated with apnoea-hypopnoea index (ptrend = 0.022), after adjusting for age, sex, socio-economic parameters, smoking habits, waist circumference, physical activity level, adequacy of night-time sleep, diet's quality as assessed by a relevant score, insulin resistance and C-reactive protein levels). Multiple logistic regression analysis also showed that energy-adjusted refined grain intake was associated with increased likelihood of severe OSA (odds ratio = 1.56, 95% confidence interval = 1.06-2.30). Νo association between apnoea/hypopnoea indices and non-refined grain intake was observed in this study. CONCLUSIONS: The findings show that obstructive sleep apnoea (OSA) is associated with cereal grain intake and suggest that a higher intake of refined cereal grains may be a risk factor for OSA severity.

Dose-response relationship between weight loss and improvements in obstructive sleep apnea severity after a diet/lifestyle interventions: secondary analyses of the "MIMOSA" randomized clinical trial.

STUDY OBJECTIVES: Lifestyle-induced weight loss is a complementary therapeutic approach for obstructive sleep apnea (OSA). We aimed at identifying the dose-response relationship between weight loss and OSA severity improvement. METHODS: This is a secondary analysis of a 6-month clinical trial in 180 adult, overweight/obese moderate-to-severe OSA patients. Participants were randomized to a standard care, a Mediterranean diet, or a Mediterranean lifestyle arm. All patients were prescribed with continuous positive airway pressure (CPAP), while intervention arms additionally participated in a weight-loss dietary/lifestyle intervention. Based on percent change in weight at 6 months, participants were categorized into a weight-stable/gain (WS/GG) group or 3 weight-loss groups (WLG): < 5%WLG, 5%-10%WLG, and ≥ 10%WLG. Polysomnographic data and OSA symptoms were evaluated preintervention and postintervention. RESULTS: Respiratory events and oximetry indices improved only in patients who lost weight and improvements were proportional to the degree of weight loss. Median percent change in apnea-hypopnea index (AHI) was -11.7%, - 37.9%, and - 49.3% in the < 5%WLG, 5%-10%WLG, and ≥ 10%WLG, respectively (P < .001). Compared to the WS/GG, the age-, sex-, baseline-, and CPAP use-adjusted relative risk (95% confidence interval) of severe OSA (AHI ≥ 30 events/h) was 0.45 (0.23-0.87) in the 5%-10%WLG and 0.32 (0.17-0.64) in the ≥ 10%WLG; the risk was also lower in the ≥ 10%WLG vs the < 5%WLG (0.42 [0.22-0.82]). Insomnia and daytime sleepiness also improved more in participants exhibiting ≥ 5% weight loss. CONCLUSIONS: Even a < 5% weight loss can reduce respiratory events, but a ≥ 5% and ideally ≥ 10% weight loss is necessary for reducing the prevalence of severe OSA. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Mediterranean Diet/Lifestyle Intervention in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT02515357; Identifier: NCT02515357. CITATION: Georgoulis M, Yiannakouris N, Kechribari I, et al. Dose-response relationship between weight loss and improvements in obstructive sleep apnea severity after a diet/lifestyle intervention: secondary analyses of the "MIMOSA" randomized clinical trial. J Clin Sleep Med. 2022;18(5):1251-1261.

The Role of Pythagorean Self-Awareness Intervention in Obstructive Sleep Apnea. A Randomized Controlled Trial.

Obstructive sleep apnea (OSA) is a chronic disease causing daytime sleepiness and poor sleep and life quality. So far, its repercussions on psychological health have been poorly addressed in the available literature. The aim of this study was to investigate the effect of a cognitive-based stress management technique, called the Pythagorean Self-Awareness Intervention (PSAI), in patients with OSA. In this randomized controlled (parallel usual care group) trial with a 1:1 allocation ratio, patients in the intervention group (N = 30, 59.7 ± 9.4 years old, 15 females) received PSAI for 8 weeks along with continuous positive airway pressure (CPAP) treatment, while patients in the control group (N = 30, 58.9 ± 9.3, 22 females) received CPAP alone. The primary endpoint included OSA symptoms. Secondary endpoints were sleepiness, sleep quality, depression-anxiety-stress, and affect. All 30 patients in the intervention group showed 100% compliance with PSAI. There was a statistically significant reduction in OSA symptoms in the intervention group compared to the control group (p = 0.021). With regard to secondary endpoints, there were statistically significant improvements in sleep quality (p = 0.001) and positive (p = 0.001) and negative affects (p < 0.001) in the PSAI group versus controls. No side effects were reported by the patients. PSAI may be useful as a complementary tool for the management of patients suffering from OSA. Larger randomized controlled trials are required to validate the results of this study.

The effectiveness of a weight-loss Mediterranean diet/lifestyle intervention in the management of obstructive sleep apnea: Results of the "MIMOSA" randomized clinical trial.

BACKGROUND & AIMS: Although continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnea (OSA), lifestyle interventions have also emerged as complementary therapeutic choices. We aimed to explore whether the addition of a weight-loss Mediterranean diet/lifestyle intervention to OSA standard care, i.e. CPAP prescription and brief written healthy lifestyle advice, has an incremental effect on improving OSA severity, over the effect of standard care alone. METHODS: We designed a parallel, randomized, controlled, superiority clinical trial. Eligible participants were adult, overweight men and women, diagnosed with moderate-to-severe OSA [apnea-hypopnea index (AHI)≥ 15 events/h] through an attended overnight polysomnography. Participants were blindly randomized to a standard care group (SCG, n = 65), a Mediterranean diet group (MDG, n = 62) or a Mediterranean lifestyle group (MLG, n = 60). All three study groups were prescribed with CPAP. The SCG additionally received written healthy lifestyle advice, while intervention arms were subjected to a 6-month behavioral intervention aiming at weight loss and increasing adherence to the Mediterranean diet. The MLG also received counselling on physical activity and sleep habits. Polysomnographic data and OSA symptoms were evaluated pre- and post-intervention. RESULTS: A total of 187 OSA patients were recruited. Seven patients were excluded post-randomization and 53/180 (29%) were lost to follow-up. No harms from the interventions applied were reported. According to intention-to-treat analysis (n = 180), mean (95% confidence interval) AHI change was -4.2 (-7.4, -1.0) for the SCG, -24.7 (-30.4, -19.1) for the MDG and -27.3 (-33.9, -20.6) for the MLG. Post-intervention age-, sex-, baseline- and CPAP use-adjusted AHI was significantly lower in the MDG and the MLG compared to the SCG (mean difference: -18.0, and -21.2, respectively, both P < 0.001), and the differences remained significant after further adjustment for body-weight change (P = 0.004 and 0.008, respectively). Other respiratory event indices, daytime sleepiness and insomnia were also significantly lower in both intervention arms compared to the SCG (all P < 0.05). The MLG only presented higher percent rapid-eye-movement sleep and lower daytime sleepiness compared to the MDG (both P < 0.05). Results were similar in the per-protocol analysis (n = 127). CONCLUSIONS: A dietary/lifestyle intervention on top of standard care leads to greater improvements in OSA severity and symptomatology compared to standard care alone. Benefits are evident regardless of CPAP use and weight loss. TRIAL REGISTRATION: Clinicaltrials.gov NCT02515357, https://clinicaltrials.gov/ct2/show/NCT02515357.

Restless Legs Syndrome masquerades as chronic insomnia.

OBJECTIVE: The objective of this study is to emphasize the importance of the clinical suspicion of Restless Legs Syndrome (RLS) among patients with chronic insomnia. METHODS: We conducted a retrospective study referring to the period 2009-2018. All patients presenting with the complaint of insomnia and fulfilling the criteria of Chronic Insomnia (C.I.) were enrolled. In this group we estimated how many patients finally had the diagnosis of RLS. Demographic and clinical characteristics (sleep related problems, fatigue, daytime sleepiness and psychological profile) were recorded and analyzed between C.I. and RLS patients using logistic regression models. RESULTS: A total of 532 patients presented with C.I. Among them 83 proved to have RLS. No differences in frequencies or odds were observed concerning the type of insomnia, daily fatigue, daytime sleepiness and depression. RLS is more frequent in women (p = 0.01) and in older patients (p = 0.05) who present with the picture of C.I. Anxiety levels are higher in the RLS group (p = 0.004). CONCLUSION: RLS and C.I. patients demonstrate a very similar profile which complicates the differential diagnosis. Physicians and especially psychiatrists who deal with insomnia must have increased clinical suspicion for RLS as RLS and insomnia have a totally different therapeutic approach.

Cardiometabolic Benefits of a Weight-Loss Mediterranean Diet/Lifestyle Intervention in Patients with Obstructive Sleep Apnea: The "MIMOSA" Randomized Clinical Trial.

Although continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnea (OSA), its cardiometabolic benefits are questionable. Our aim was to explore whether the combination of a weight-loss Mediterranean diet/lifestyle intervention with OSA standard care leads to greater cardiometabolic improvements compared with standard care alone. We randomly assigned 187 adult, overweight, polysomnography-diagnosed moderate-to-severe OSA patients to a standard care group (SCG, n = 65), a Mediterranean diet group (MDG, n = 62) or a Mediterranean lifestyle group (MLG, n = 60). All three groups were prescribed with CPAP. Additionally, the SCG only received brief written healthy lifestyle advice, while intervention arms were subjected to a six-month weight-loss behavioral intervention based on the Mediterranean diet. The MLG also received guidance for improving physical activity and sleep habits. Glucose metabolism indices, blood lipids, liver enzymes and blood pressure improved only in intervention arms, and were significantly lower compared to the SCG post-intervention (all p < 0.05). The age-, sex-, baseline- and CPAP use-adjusted relative risk (95% confidence interval) of metabolic syndrome was 0.58 (0.34-0.99) for the MDG and 0.30 (0.17-0.52) for the MLG compared to the SCG. The MLG additionally presented a lower relative risk of metabolic syndrome compared to the MDG (0.52 (0.30-0.89)). After further adjustment for body-weight change, a lower relative risk of metabolic syndrome was still evident for the MLG compared to the SCG. In conclusion, although standard care alone does not improve OSA patients' cardiometabolic profile, its combination with a weight-loss Mediterranean diet/lifestyle intervention leads to significant cardiometabolic benefits.

Τhe Co-Existence of Obstructive Sleep Apnea and Bronchial Asthma: Revelation of a New Asthma Phenotype?

Bronchial asthma (BA) and obstructive sleep apnea (OSA) are common respiratory obstructive diseases that may coexist. It would be interesting to study the possible influence of that coexistence on both diseases. Until now, reviews focused mainly on epidemiology. The aim of this study was to review the literature in relation to epidemiology, pathophysiology, consequences, screening of patients, and treatment of the coexistence of OSA and BA. We pooled studies from the PubMed database from 1986 to 2019. OSA prevalence in asthmatics was found to be high, ranging from19% to 60% in non-severe BA, reaching up to 95% in severe asthma. Prevalence was correlated with the duration and severity of BA, and increased dosage of steroids taken orally or by inhalation. This high prevalence of the coexistence of OSA and BA diseases could not be a result of just chance. It seems that this coexistence is based on the pathophysiology of the diseases. In most studies, OSA seems to deteriorate asthma outcomes, and mainly exacerbates them. CPAP (continuous positive airway pressure) treatment is likely to improve symptoms, the control of the disease, and the quality of life in asthmatics with OSA. However, almost all studies are observational, involving a small number of patients with a short period of follow up. Although treatment guidelines cannot be released, we could recommend periodic screening of asthmatics for OSA for the optimal treatment of both the diseases.

Complex sleep apnea after full-night and split-night polysomnography: the Greek experience.

PURPOSE: Treatment-emergent central sleep apnea (TE-CSA) is defined as the emergence or persistence of central respiratory events during the initiation of positive airway pressure (PAP) without a back-up rate in obstructive sleep apnea (OSA) patients and after significant resolution of obstructive events. Previous studies have estimated a prevalence from 0.56 to 20.3%. The aim of this study was to establish the prevalence of TE-CSA in a Greek adult population. METHODS: One thousand fifty nine patients with newly diagnosed OSA, who were referred to the Sleep Disorders Center of Evangelismos Hospital of Athens over an 18-month period, were included in this study. A split-night polysomnography (PSG), or two formal overnight PSGs (diagnostic and continuous PAP (CPAP) titration study), were performed. RESULTS: Patients with OSA were divided in two groups; the first group included 277 patients, who underwent two separate studies (diagnostic and CPAP titration study), and the second group 782 patients, who underwent split-night studies. The prevalence of TE-CSA in the first group was 2.53% (7 patients), and in the second group was 5.63% (44 patients). CONCLUSIONS: The prevalence of TE-CSA in Greece was lower compared to most previous reported studies. The significant variation in the prevalence of TE-CSA between different centers throughout the world is mainly associated with the used diagnostic criteria as well as methodological and technical aspects.

Heart rate variability is augmented in patients with positional obstructive sleep apnea, but only supine LF/HF index correlates with its severity.

PURPOSE: Data on cardiac autonomic functioning, as expressed by heart rate variability (HRV), in patients with positional obstructive sleep apnea (p-OSA) disorder are lacking. The purpose of the study was to compare HRV indices between sleep segments derived from supine body position and another body position with and without apneic events, respectively. Our intention was to find some correlation between HRV indices and the pathophysiological characteristics of the corresponding temporal period. METHODS: Nocturnal polysomnograms derived from twenty-seven patients (22 men) with documented positional apnea were retrospectively reviewed. Patients never treated for OSA and free from diseases/drugs altering HRV were examined. Data from total sleep studies were collected. Two N2 sleep segments, from supine body position with sleep-disordered breathing (SDB) and another body position without SDB were analyzed. Apneic events (namely, apneas, hypopneas, and respiratory effort-related arousals (RERAs)), arousals, number of desaturations, minimum pulse oximetry (SaO2min), time domain variables (average RR, SDNN, SDSD, RMSSD, pNN50, and HRV triangular index) and frequency domain variables (VLF, LF, HF, TP, LF/HF) were recorded for both temporal periods. RESULTS: With the exception of average RR and HF, all other variables were significantly higher in segments with SDB. Only LF/HF_supine ratio was positively correlated with the apneic_supine_index (t = 3.13, p < 0.01) and negatively correlated with SaO2min (t = -2.9, p < 0.01) and the desaturation_supine_index (t = -2.5, p = 0.02). Arousals were negatively correlated with SaO2min (t = -2.8, p < 0.01). CONCLUSIONS: SDB augments autonomic tone in patients with p-OSA, but only LF/HF correlates with its severity and might be used as a screening tool in the future. On the contrary, parasympathetic tone, as reflected by HF, remains constant in both periods.

Sleep in frontotemporal dementia is equally or possibly more disrupted, and at an earlier stage, when compared to sleep in Alzheimer's disease.

BACKGROUND: Conversely to other neurodegenerative diseases (i.e., Alzheimer's disease, AD), sleep in frontotemporal dementia (FTD) has not been studied adequately. Although some evidence exists that sleep-wake disturbances occur in FTD, very little is known regarding sleep macrostructure and/or primary sleep disorders. OBJECTIVE: To investigate these issues in this population and compare them to similar issues in AD and in healthy elderly (HE). METHODS: Twelve drug-naïve behavioral-variant FTD (bvFTD) patients (7 men/5 women) of mean age 62.5 ± 8.6 years were compared to seventeen drug-naïve AD patients (8 men/9 women) of mean age 69.0 ± 9.9 years and twenty drug-naïve HE (12 men/8 women) of mean age 70.2 ± 12.5 years. All participants were fully assessed clinically, through a sleep questionnaire, an interview, and video-polysomnography recordings. RESULTS: The two patient groups were comparably cognitively impaired. However, compared to FTD patients, the AD patients had a statistically significant longer disease duration. Overall, the sleep profile was better preserved in HE. Sleep complaints did not differ considerably between the two patient groups. Sleep parameters and sleep macrostructure were better preserved in AD compared to FTD patients, regardless of primary sleep disorders, which occurred equally in the two groups. CONCLUSIONS: With respect to AD, FTD patients had several sleep parameters similarly or even more affected by neurodegeneration, but in a much shorter time span. The findings probably indicate a centrally originating sleep deregulation. Since in FTD patients sleep disturbances may be obvious from an early stage of their disease, and possibly earlier than in AD patients, physicians and caregivers should be alert for the early detection and treatment of these symptoms.