CPAP resumption after a first termination and impact on all-cause mortality in France.

BACKGROUND: Continuation of continuous positive airway pressure (CPAP) therapy after initial prescription has been shown to reduce all-cause mortality versus therapy termination. However, there is a lack of data on the rates and impact of resuming CPAP in patients with obstructive sleep apnoea (OSA). This analysis determined the prevalence of CPAP resumption in the year after termination, characterised determinants of CPAP resumption, and examined the impact of CPAP resumption on all-cause mortality. METHODS: French national health insurance reimbursement system data for adults aged ≥18 years were used. CPAP prescription was identified by specific treatment codes. Patients who resumed CPAP after first therapy termination and continued to use CPAP for 1 year were matched with those who resumed CPAP then terminated therapy for a second time. RESULTS: Out of 103 091 individuals with a first CPAP termination, 26% resumed CPAP over the next 12 months, and 65% of these were still using CPAP 1 year later. Significant predictors of CPAP continuation after resumption included male sex, hypertension and CPAP prescription by a pulmonologist. In the matched population, the risk of all-cause death was 38% lower in individuals who continued using CPAP after therapy resumption versus those who had a second therapy discontinuation (hazard ratio 0.62, 95% CI 0.48-0.79; p=0.0001). CONCLUSION: These data suggest that individuals with OSA who fail initial therapy with CPAP should be offered a second trial with the device to ensure that effective therapy is not withheld from those who might benefit.

Effect of mandibular advancement splint therapy on cardiac autonomic function in obstructive sleep apnoea.

PURPOSE: This study aimed to evaluate the effect of mandibular advancement splint (MAS) therapy on cardiac autonomic function in patients with obstructive sleep apnoea (OSA) using heart rate variability (HRV) analysis. METHODS: Electrocardiograms (ECG) derived from polysomnograms (PSG) of three prospective studies were used to study HRV of patients with OSA before and after MAS treatment. HRV parameters were averaged across the entire ECG signal during N2 sleep using 2-min epochs shifted by 30 s. Paired t-tests were used to compare PSG and HRV measures before and after treatment, and the percent change in HRV measures was regressed on the percent change in apnoea-hypopnea index (AHI). RESULTS: In 101 patients with OSA, 72% were Caucasian, 54% men, the mean age was 56 ± 11 years, BMI 29.8 ± 5.3 kg/m2, and treatment duration was 4.0 ± 3.2 months. After MAS therapy, there was a significant reduction in OSA severity (AHI, - 18 ± 16 events per hour, p < 0.001) and trends towards increased low-frequency to high-frequency ratio, low-frequency power, and reduced high-frequency power (LF:HF, - 0.4 ± 1.5, p = 0.01; LF, - 3 ± 16 nu, p = 0.02, HF, 3.5 ± 13.7 nu, p = 0.01). Change in NN intervals correlated with the change in AHI (ß(SE) = - 2.21 (0.01), t = - 2.85, p = 0.005). No significant changes were observed in the time-domain HRV markers with MAS treatment. CONCLUSION: The study findings suggest that successful MAS treatment correlates with changes in HRV, specifically the lengthening of NN intervals, a marker for improved cardiac autonomic adaptability.

Upper airway morphology in adults with positional obstructive sleep apnea.

PURPOSE: To compare the anatomical balance and shape of the upper airway in the supine position between adults with positional obstructive sleep apnea (POSA) and adults with non-positional OSA (NPOSA). METHODS: Adults diagnosed with OSA (apnea-hypopnea index (AHI) > 10 events/h) were assessed for eligibility. POSA was defined as the supine AHI more than twice the AHI in non-supine positions; otherwise, patients were classified as NPOSA. Cone beam computed tomography (CBCT) imaging was performed for every participant while awake in the supine position. The anatomical balance was calculated as the ratio of the tongue size to the maxillomandibular enclosure size. The upper airway shape was calculated as the ratio of the anteroposterior dimension to the lateral dimension at the location of the minimal cross-sectional area of the upper airway (CSAmin-shape). RESULTS: Of 47 participants (28 males, median age [interquartile range] 56 [46 to 63] years, median AHI 27.8 [15.0 to 33.8]), 34 participants were classified as having POSA (72%). The POSA group tended to have a higher proportion of males and a lower AHI than the NPOSA group (P = 0.07 and 0.07, respectively). After controlling for both sex and AHI, the anatomical balance and CSAmin-shape were not significantly different between both groups (P = 0.18 and 0.73, respectively). CONCLUSION: Adults with POSA and adults with NPOSA have similar anatomical balance and shape of their upper airway in the supine position. TRIAL REGISTRATION: This study was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR Trial ACTRN12611000409976).

Cardiac autonomic function in REM-related obstructive sleep apnoea: insights from nocturnal heart rate variability profiles.

PURPOSE: In light of the reported association between REM-related obstructive sleep apnoea (OSA) and heightened cardiovascular risk, this study aims to compare cardiac autonomic function in patients with REM-OSA and OSA independent of sleep stage. We hypothesized that REM-OSA patients would exhibit higher sympathetic cardiac modulation based on heart rate variability (HRV) profiles. METHODS: HRV was compared between the OSA group (AHI ≥ 5 events/h, n = 252) and the REM-OSA group (AHI ≥ 5 events/h, AHIREM:AHINREM ≥ 2, n = 137). Time- and frequency-domain measures of HRV were analysed during N2 and REM sleep. RESULTS: Clinical characteristics between the two test groups differed significantly, 45% of REM-OSA patients were female, with mild OSA (median, interquartile range (IQR)) AHI of 10 (7) events/h. Only 26% of the OSA cohort were female with moderate OSA (AHI = 17 (20) events/h, p < 0.001). Compared with the OSA group, the low frequency to high frequency ratio (LF:HF) and LF power were lower and HF power was higher in the REM-OSA group during N2 (LF:HF, p = 0.012; LF; p = 0.013; HF, p = 0.007) and in REM sleep (LF:HF, p = 0.002; LF, p = 0.004; HF, p < 0.001). Patient sex and OSA severity had a significant combined effect on average N to N interval, LF power, and LF:HF ratio during N2 and REM sleep (all p < 0.001). CONCLUSION: Contrary to our hypothesis, REM-OSA patients demonstrated consistently higher cardiac vagal modulation, reflecting better cardiac autonomic adaptation. These results were attributed to differences in OSA severity and sex in these two groups, both independently affecting HRV. This study emphasises the need for future research into the underlying pathophysiology of REM-OSA and the potential implications of sex and OSA severity on cardiovascular risk.

Standardised Tool for the Assessment of Bruxism.

OBJECTIVE: This paper aims to present and describe the Standardised Tool for the Assessment of Bruxism (STAB), an instrument that was developed to provide a multidimensional evaluation of bruxism status, comorbid conditions, aetiology and consequences. METHODS: The rationale for creating the tool and the road map that led to the selection of items included in the STAB has been discussed in previous publications. RESULTS: The tool consists of two axes, specifically dedicated to the evaluation of bruxism status and consequences (Axis A) and of bruxism risk and etiological factors and comorbid conditions (Axis B). The tool includes 14 domains, accounting for a total of 66 items. Axis A includes the self-reported information on bruxism status and possible consequences (subject-based report) together with the clinical (examiner report) and instrumental (technology report) assessment. The Subject-Based Assessment (SBA) includes domains on Sleep Bruxism (A1), Awake Bruxism (A2) and Patient's Complaints (A3), with information based on patients' self-report. The Clinically Based Assessment (CBA) includes domains on Joints and Muscles (A4), Intra- and Extra-Oral Tissues (A5) and Teeth and Restorations (A6), based on information collected by an examiner. The Instrumentally Based Assessment (IBA) includes domains on Sleep Bruxism (A7), Awake Bruxism (A8) and the use of Additional Instruments (A9), based on the information gathered with the use of technological devices. Axis B includes the self-reported information (subject-based report) on factors and conditions that may have an etiological or comorbid association with bruxism. It includes domains on Psychosocial Assessment (B1), Concurrent Sleep-related Conditions Assessment (B2), Concurrent Non-Sleep Conditions Assessment (B3), Prescribed Medications and Use of Substances Assessment (B4) and Additional Factors Assessment (B5). As a rule, whenever possible, existing instruments, either in full or partial form (i.e. specific subscales), are included. A user's guide for scoring the different items is also provided to ease administration. CONCLUSIONS: The instrument is now ready for on-field testing and further refinement. It can be anticipated that it will help in collecting data on bruxism in such a comprehensive way to have an impact on several clinical and research fields.

Intermittent hypoxia enhances the expression of hypoxia inducible factor HIF1A through histone demethylation.

The cellular response to hypoxia is regulated through enzymatic oxygen sensors, including the prolyl hydroxylases, which control degradation of the well-known hypoxia inducible factors (HIFs). Other enzymatic oxygen sensors have been recently identified, including members of the KDM histone demethylase family. Little is known about how different oxygen-sensing pathways interact and if this varies depending on the form of hypoxia, such as chronic or intermittent. In this study, we investigated how two proposed cellular oxygen-sensing systems, HIF-1 and KDM4A, KDM4B, and KDM4C, respond in cells exposed to rapid forms of intermittent hypoxia (minutes) and compared to chronic hypoxia (hours). We found that intermittent hypoxia increases HIF-1α protein through a pathway distinct from chronic hypoxia, involving the KDM4A, KDM4B, and KDM4C histone lysine demethylases. Intermittent hypoxia increases the quantity and activity of KDM4A, KDM4B, and KDM4C, resulting in a decrease in histone 3 lysine 9 (H3K9) trimethylation near the HIF1A locus. We demonstrate that this contrasts with chronic hypoxia, which decreases KDM4A, KDM4B, and KDM4C activity, leading to hypertrimethylation of H3K9 globally and at the HIF1A locus. Altogether, we found that demethylation of histones bound to the HIF1A gene in intermittent hypoxia increases HIF1A mRNA expression, which has the downstream effect of increasing overall HIF-1 activity and expression of HIF target genes. This study highlights how multiple oxygen-sensing pathways can interact to regulate and fine tune the cellular hypoxic response depending on the period and length of hypoxia.

Influence of poor sleep on cardiovascular disease-free life expectancy: a multi-resource-based population cohort study.

BACKGROUND: The complexity of sleep hinders the formulation of sleep guidelines. Recent studies suggest that different unhealthy sleep characteristics jointly increase the risks for cardiovascular disease (CVD). This study aimed to estimate the differences in CVD-free life expectancy between people with different sleep profiles. METHODS: We included 308,683 middle-aged adults from the UK Biobank among whom 140,181 had primary care data linkage. We used an established composite sleep score comprising self-reported chronotype, duration, insomnia complaints, snoring, and daytime sleepiness to derive three sleep categories: poor, intermediate, and healthy. We also identified three clinical sleep disorders captured by primary care and inpatient records within 2 years before enrollment in the cohort: insomnia, sleep-related breathing disorders, and other sleep disorders. We estimated sex-specific CVD-free life expectancy with three-state Markov models conditioning on survival at age 40 across different sleep profiles and clinical disorders. RESULTS: We observed a gradual loss in CVD-free life expectancy toward poor sleep such as, compared with healthy sleepers, poor sleepers lost 1.80 [95% CI 0.96-2.75] and 2.31 [1.46-3.29] CVD-free years in females and males, respectively, while intermediate sleepers lost 0.48 [0.41-0.55] and 0.55 [0.49-0.61] years. Among men, those with clinical insomnia or sleep-related breathing disorders lost CVD-free life by 3.84 [0.61-8.59] or 6.73 [5.31-8.48] years, respectively. Among women, sleep-related breathing disorders or other sleep disorders were associated with 7.32 [5.33-10.34] or 1.43 [0.20-3.29] years lost, respectively. CONCLUSIONS: Both self-reported and doctor-diagnosed poor sleep are negatively associated with CVD-free life, especially pronounced in participants with sleep-related breathing disorders.

Healthcare resource utilisation and costs in patients with treated obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a highly prevalent yet underdiagnosed disease that creates a large economic burden on the United States healthcare system. In this retrospective study, we tested the hypothesis that adherence to positive airway pressure (PAP) therapy, the 'gold standard' treatment for OSA, is associated with reduced healthcare resource utilisation and costs. We linked de-identified payer-sourced medical claims and objective PAP usage data for patients newly diagnosed with OSA. Inverse probability of treatment weighting was used to create balanced groups of patients who were either adherent, intermediately adherent, or non-adherent to PAP therapy. From a sample of 179,542 patients (average age 52.5 years, 61% male), 37% were adherent, 40% intermediate, and 23% non-adherent. During the first year, PAP adherence was significantly associated with fewer emergency room visits (mean [SD] adherent: 0.39 [1.20] versus intermediate: 0.47 [1.30], p < 0.001; versus non-adherent: 0.54 [1.44], p < 0.001), all-cause hospitalisations (mean [SD] adherent: 0.09 [0.43] versus intermediate: 0.12 [0.51], p < 0.001; versus non-adherent: 0.13 [0.55], p < 0.001), and lower total costs (mean [SD] adherent $5874 [8045] versus intermediate $6523 [9759], p < 0.001; versus non-adherent $6355 [10,517], p < 0.001). Results were similar in the second year of PAP use. These results provide additional evidence from a large, diverse sample to support the diagnosis and treatment of OSA and encourage long-term adherence to PAP therapy.

Impact of Positive Airway Pressure Therapy Adherence on Outcomes in Patients with Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease.

Rationale: The co-occurrence of obstructive sleep apnea and chronic obstructive pulmonary disease, termed overlap syndrome, has a poor prognosis. However, data on positive airway pressure (PAP) treatments and their impact on outcomes and costs are lacking. Objectives: This retrospective observational study investigated the effects of PAP on health outcomes, resource usage, and costs in patients with overlap syndrome. Methods: Deidentified adjudicated claims data for patients with overlap syndrome in the United States were linked to objectively measured PAP user data. Patients were considered adherent to PAP therapy if they met Centers for Medicare and Medicaid Services criteria for eight 90-day timeframes from device setup through 2-year follow-up. Propensity score matching was used to create comparable groups of adherent and nonadherent patients. Healthcare resource usage was based on the number of doctor visits, all-cause emergency room visits, all-cause hospitalizations, and PAP equipment and supplies, and proxy costs were obtained. Measurements and Main Results: A total of 6,810 patients were included (mean age, 60.8 yr; 56% female); 2,328 were nonadherent. Compared with the year before therapy, there were significant reductions in the number of emergency room visits, hospitalizations, and severe acute exacerbations during 2 years of PAP therapy in patients who were versus were not adherent (all P < 0.001). This improvement in health status was paralleled by a significant reduction in the associated healthcare costs. Conclusions: PAP usage by patients with overlap syndrome was associated with reduced all-cause hospitalizations and emergency room visits, severe acute exacerbations, and healthcare costs.

Effect of Weight Loss and Continuous Positive Airway Pressure on Obstructive Sleep Apnea and Metabolic Profile Stratified by Craniofacial Phenotype: A Randomized Clinical Trial.

Rationale: Craniofacial structure is believed to modulate the effect of weight loss on obstructive sleep apnea (OSA), but whether this affects metabolic profile after weight loss compared with continuous positive airway pressure (CPAP) is unknown among obese Chinese patients with OSA. Objectives: To compare the change in metabolic profile between a lifestyle modification program (LMP), stratified by craniofacial phenotype, and CPAP therapy for 6 months. Methods: We randomly assigned 194 patients with body mass index ⩾ 25 kg/m2 and moderate to severe OSA to participate in the LMP or receive CPAP therapy for 6 months in a 2:1 ratio. Assessments included computed tomography for assessing maxillomandibular volume (MMV), hsCRP (high-sensitivity C-reactive protein), and insulin sensitivity. Measurements and Main Results: Among 128 and 66 subjects in the LMP and CPAP groups, respectively, hsCRP was reduced more in the LMP group than the CPAP group (median [interquartile range], -0.7 [-1.4 to -0.0] vs. -0.3 [-0.9 to 0.4] mg/L; P = 0.012). More patients in the LMP group achieved low hsCRP (<1 mg/L) than the CPAP group (21.1% vs. 9.1%; P = 0.04). Insulin sensitivity improved only in the LMP group, with 3.1 (95% confidence interval, 1.5-6.6) times more patients with normal glucose regulation after intervention. The LMP group was stratified into LMP-small MMV (n = 64) and LMP-large MMV (n = 64) groups according to the median MMV value of 233.2 cm3. There was no significant difference in hsCRP (median [interquartile range], -0.7 [-1.3 to 0.1] vs. -0.7 [-1.5 to -0.2] mg/L; P = 0.884) and insulin sensitivity (median [interquartile range], 0.5 [-0.2 to 1.9] vs. 0.6 [0.1 to 2.0]; P = 0.4860) between the LMP-small MMV and LMP-large MMV groups. Conclusions: Weight reduction alleviated subclinical inflammation and improved insulin sensitivity more than CPAP among obese Chinese patients with moderate to severe OSA, and this effect was not influenced by craniofacial structure. Clinical trial registered with www.clinicaltrials.gov (NCT03287973).

The effect of surgical weight loss on upper airway fat in obstructive sleep apnoea.

PURPOSE: Obesity is a reversible risk factor for obstructive sleep apnoea (OSA). Weight loss can potentially improve OSA by reducing fat around and within tissues surrounding the upper airway, but imaging studies are limited. Our aim was to study the effects of large amounts of weight loss on the upper airway and volume and fat content of multiple surrounding soft tissues. METHODS: Participants undergoing bariatric surgery were recruited. Magnetic resonance imaging (MRI) was performed at baseline and six-months after surgery. Volumetric analysis of the airway space, tongue, pharyngeal lateral walls, and soft palate were performed as well as calculation of intra-tissue fat content from Dixon imaging sequences. RESULTS: Among 18 participants (89% women), the group experienced 27.4 ± 4.7% reduction in body weight. Velopharyngeal airway volume increased (large effect; Cohen's d [95% CI], 0.8 [0.1, 1.4]) and tongue (large effect; Cohen's d [95% CI], - 1.4 [- 2.1, - 0.7]) and pharyngeal lateral wall (Cohen's d [95% CI], - 0.7 [- 1.2, - 0.1]) volumes decreased. Intra-tissue fat decreased following weight loss in the tongue, tongue base, lateral walls, and soft palate. There was a greater effect of weight loss on intra-tissue fat than parapharyngeal fat pad volume (medium effect; Cohen's d [95% CI], - 0.5 [- 1.2, 0.1], p = 0.083). CONCLUSION: The study showed an increase in velopharyngeal volume, reduction in tongue volume, and reduced intra-tissue fat in multiple upper airway soft tissues following weight loss in OSA. Further studies are needed to assess the effect of these anatomical changes on upper airway function and its relationship to OSA improvement.

Comparative efficacy of mandibular advancement devices in obstructive sleep apnea: a network meta-analysis.

PURPOSE: To analyze relative efficacies of mandibular advancement devices (MAD) in sleep apnea treatment. METHODS: From eligible randomized controlled trials (RCT), MADs were classified based on their mechanistic designs. Data on apnea-hypopnea index (AHI), Epworth sleepiness scale (ESS), nadir oxygen saturation (minSaO2), and sleep efficiency (SE%) from RCTs were then analyzed in network meta-analyses, and relative ranking of different MADs was computed based on P scores (a method of ranking similar to SUCRA). Similar analyses were conducted based on the different brands of MADs. RESULTS: There were no statistically significant differences between MADs in any of the outcomes analyzed. However, the P-scores, based on the point estimates and standard errors of the network estimates, ranked some MADs higher than others in some of the outcomes. Of the different mechanistic designs, the highest P scores were achieved for attached midline traction (P score = 0.84) and unattached bilateral interlocking (P score = 0.78) devices for AHI reduction, attached bilateral traction (P score = 0.78) and unattached bilateral interlocking (P score = 0.76) for ESS, monobloc (P score = 0.91) and unattached bilateral interlocking (P score = 0.64) for minSaO2, and unattached bilateral interlocking (P score = 0.82) and attached bilateral traction (P score = 0.77) for SE%. Notable findings in the network meta-analyses based on MAD brands, of the limited number of studies that specified them were the effects of SomnoDent Flex™, TAP™, and IST® in their effects on AHI reduction, with P scores of 0.94, 0.83, and 0.82, respectively. Monobloc decreased supine-AHI the most (- 44.46 [- 62.55; - 26.36], P score = 0.99), and unattached bilateral interlocking had the greatest effect on REM-AHI (- 11.10 [- 17.10; - 5.10], P score = 0.87). CONCLUSIONS: Findings from this study show clinically (but not statistically) significant differences between MADs in terms of their relative efficacy when analyzed for different sleep apnea treatment outcomes and sleep apnea phenotypes.

Impact of hospitalisation on behavioural and physiological stress responses associated with cardiovascular risk in visiting family members.

BACKGROUND: The hospitalisation of a patient in intensive care impacts the psychological health of family members, with a high prevalence of anxiety, depression, and post-traumatic stress symptoms reported among families of critically ill patients. Understanding of the behavioural and physiological impact is limited and presents a new area of focus. OBJECTIVES: The objective of this study was to evaluate behavioural and physiological stress responses of visiting family members following hospitalisation of their adult relative. METHODS: Prospective longitudinal evaluation included 40 family members of adult patients with admission to intensive or coronary care in a large tertiary care metropolitan hospital. Assessments were conducted at three timepoints: in-hospital within 1 week of admission and 2 weeks and 3 months post discharge. Assessments included duration and quality of sleep (self-reported and actigraphy measured), physical activity, dietary and alcohol patterns, resting heart rate and blood pressure, and morning blood cortisol and lipid levels. Assessment of a reference group of 40 non-hospital-exposed control participants was also conducted. RESULTS: At the in-hospital assessment, study participants reported lower sleep time, altered 24-h physical activity patterns, reduced dietary and alcohol intake, and higher systolic and diastolic blood pressure than a nonhospitalised reference group. Compared to in-hospital assessment, these altered behavioural and physiological responses improved over time except for systolic blood pressures which remained unchanged at 3 months post family member discharge. CONCLUSION: Hospitalisation is associated with altered behavioural and physiological responses in family members. These findings contribute to understanding of the impact of unexpected hospitalisation on family members' cardiovascular risk factors and provide insights into potential mechanisms for the proposed increased risk during this time. Elevated systolic blood pressure at 3 months post discharge suggests a prolonged cardiovascular stress response in many family members of critical care patients that requires further study, with a focus on contributing and potential modifiable factors.

Effectiveness of a patient-centred sleep study report in the management of obstructive sleep apnoea.

PURPOSE: Obstructive sleep apnoea (OSA) is a common condition with a range of short- and long-term health implications. Providing patient-centred care is a key principle to ensure patients are well informed and empowered to participate in clinical decision making. This study aimed to develop a patient-centred sleep study report for patients with obstructive sleep apnoea and to determine whether or not its implementation led to improved patient understanding of their disease. METHODS: The study was performed in two phases. The first phase utilised the Delphi-survey technique to develop and critically appraise a patient-centred sleep study report (PCSR) for patients with OSA, to accurately and simply convey key components of the patient's diagnosis and management. The second phase was a prospective, randomised controlled trial to assess the effect of the PCSR on patient knowledge, self-efficacy, and understanding as measured through validated patient questionnaires. RESULTS: The PCSR was developed on key concepts deemed to be important by the surveyed physicians, senior sleep scientists and patients. This included ensuring the results were customised, highlighting the patient's apnoea-hypopnea index, oxygen desaturation index and arousal index and limiting technical information to a few key pieces. Patients randomised to receive the PCSR had improved understanding and perceived patient-physician interaction compared to those randomised to standard care. CONCLUSION: The development and implementation of the PCSR was feasible and improved patient understanding and perceived patient-physician interaction in patients with moderate to severe OSA. Whether or not use of the PCSR will translate to improved compliance with therapy will require further evaluation.

Mandibular Advancement Splint Therapy.

Mandibular advancement splint (MAS) therapy is the leading alternative to continuous positive airway pressure (CPAP) therapy for the treatment of obstructive sleep apnoea. A MAS is an oral appliance which advances the mandible in relation to the maxilla, thus increasing airway calibre and reducing collapsibility. Although it is less effective than CPAP in reducing the apnoea-hypopnoea index (AHI), it has demonstrated equivalence to CPAP in a number of key neurobehavioural and cardiovascular health outcomes, perhaps due to increased tolerability and patient adherence when compared to CPAP. However, response to MAS is variable, and reliable prediction tools for patients who respond best to MAS therapy have thus far been elusive; this is one of the key clinical barriers to wider uptake of MAS therapy. In addition, the most effective MAS devices are custom-made by a dentist specialising in the treatment of sleep disorders, which may present financial or accessibility barriers for some patients. MAS devices are generally well tolerated but may have side effects including temporomandibular joint (TMJ) dysfunction, hypersalivation, tooth pain and migration as well as occlusal changes. A patient-centred approach to treatment from a multidisciplinary team perspective is recommended. Evidence-based clinical practice points and areas of future research are summarised at the conclusion of the chapter.

Sleep and physical activity in relation to all-cause, cardiovascular disease and cancer mortality risk.

OBJECTIVES: Although both physical inactivity and poor sleep are deleteriously associated with mortality, the joint effects of these two behaviours remain unknown. This study aimed to investigate the joint association of physical activity (PA) and sleep with all-cause and cause-specific mortality risks. METHODS: 380 055 participants aged 55.9 (8.1) years (55% women) from the UK Biobank were included. Baseline PA levels were categorised as high, medium, low and no moderate-to-vigorous PA (MVPA) based on current public health guidelines. We categorised sleep into healthy, intermediate and poor with an established composited sleep score of chronotype, sleep duration, insomnia, snoring and daytime sleepiness. We derived 12 PA-sleep combinations, accordingly. Mortality risks were ascertained to May 2020 for all-cause, total cardiovascular disease (CVD), CVD subtypes (coronary heart disease, haemorrhagic stroke, ischaemic stroke), as well as total cancer and lung cancer. RESULTS: After an average follow-up of 11.1 years, sleep scores showed dose-response associations with all-cause, total CVD and ischaemic stroke mortality. Compared with high PA-healthy sleep group (reference), the no MVPA-poor sleep group had the highest mortality risks for all-cause (HR (95% CIs), (1.57 (1.35 to 1.82)), total CVD (1.67 (1.27 to 2.19)), total cancer (1.45 (1.18 to 1.77)) and lung cancer (1.91 (1.30 to 2.81))). The deleterious associations of poor sleep with all outcomes, except for stroke, was amplified with lower PA. CONCLUSION: The detrimental associations of poor sleep with all-cause and cause-specific mortality risks are exacerbated by low PA, suggesting likely synergistic effects. Our study supports the need to target both behaviours in research and clinical practice.

The need for sleep and circadian education in Australian high schools: incidental results from a survey of university students.

ISSUE ADDRESSED: To describe the need for high school sleep education from the perspective of undergraduate university students. METHODS: Undergraduate students who completed an online course on sleep and circadian health were surveyed 6 months after course completion. Students were asked whether a similar course would have benefited them as high school students, and about the need for sleep education in high schools. Thematic analysis of this qualitative data was carried out. RESULTS: Eighty-nine students who had attended 71 unique high schools provided responses. Eight-one per cent thought they would have benefitted from a similar course during high school and identified domains of sleep knowledge particularly relevant to high school students. They cited environmental barriers to healthy sleep present during high school and believed that sleep education could improve students' lifestyle, sleep and performance. Nineteen per cent of students said they would not have benefited, because they perceived sleeping patterns during high school to be nonmodifiable or believed that previous sleep education was sufficient. Of the respondents who did not think students would benefit, 53% would still tell their high school principal that there was a need for sleep education. CONCLUSIONS: The findings support the need for engaging sleep education for high school students. Future studies should examine the perspectives of students in high school directly, rather than undergraduate students who have already shown an interest in sleep health. SO WHAT?: Sleep health is missing from the Australian school curriculum. Online courses may be an engaging method of promoting sleep and circadian health to high school students.

Heart rate variability and obstructive sleep apnea: Current perspectives and novel technologies.

Obstructive sleep apnea (OSA) is a highly prevalent condition, resulting in recurrent hypoxic events, sleep arousal, and daytime sleepiness. Patients with OSA are at an increased risk of cardiovascular morbidity and mortality. The mechanisms underlying the development of cardiovascular disease in OSA are multifactorial and cause a cascade of events. The primary contributing factor is sympathetic overactivity. Heart rate variability (HRV) can be used to evaluate shifts in the autonomic nervous system, during sleep and in response to treatment in patients with OSA. Newer technologies are aimed at improving HRV analysis to accelerate processing time, improve the diagnosis of OSA, and detection of cardiovascular risk. The present review will present contemporary understandings and uses for HRV, specifically in the realms of physiology, technology, and clinical management.

The bidirectional association between sleep and physical activity: A 6.9 years longitudinal analysis of 38,601 UK Biobank participants.

Although physical activity and sleep may influence each other, little is known about the bidirectional association of these two behaviors. The present analyses included 38,601 UK Biobank participants (51% female, 55.7 ± 7.6 years old, 6.9 ± 2.2 years of follow-up). Physical activity was categorized by the weekly metabolic equivalent of task minutes (highly active: ≥ 1200; active: 600 to <1200; inactive: < 600), and sleep patterns were determined using a composite score of healthy sleep characteristics: morning chronotype, adequate sleep duration (7-8 h/d), never or rare insomnia, never or rare snoring, and infrequent daytime sleepiness. We categorized the sleep score into three patterns (healthy: ≥ 4; intermediate: 2-3; poor: ≤ 1). Multiple logistic regressions examined the association of baseline (or the temporal changes in) sleep/physical activity with physical inactivity/poor sleep at follow-up. Participants with an intermediate or poor sleep pattern at baseline had higher odds (adjusted odds ratio: 1.24 [1.17, 1.32] and 1.65 [1.45, 1.88], respectively) for physical inactivity at follow-up, compared to those with healthy sleep, while shifting to a healthy sleep pattern over time attenuated these adverse associations. Compared to individuals highly active at both time points, being physically inactive at baseline and reducing physical activity over time were both associated with higher odds for poor sleep at follow-up. In conclusion, sleep improvements over time benefitted physical activity at follow-up, while reduced physical activity had a detrimental effect on sleep patterns at follow-up. Our results provide scope for interventions to concurrently target physical activity and sleep.

Development and validation of a model for diagnosis of obstructive sleep apnoea in primary care.

BACKGROUND AND OBJECTIVE: Use of in-laboratory polysomnography (PSG) to diagnose obstructive sleep apnoea (OSA) is cost and resource intensive. Questionnaires, physical measurements and home monitors have been studied as potential simpler alternatives. This study aimed to develop a diagnostic model for OSA for use in primary care. METHODS: Primary care practitioners were trained to recognize symptoms of sleep apnoea and recruited patients based on the clinical need to investigate OSA. Assessment was by symptom questionnaires, anthropomorphic measurements, digital facial photography, and a single-channel nasal flow monitor (Flow Wizard©, DiagnoseIT, Sydney, Australia) worn at home for 3 nights. The in-laboratory PSG was the reference test, with OSA defined as apnoea-hypopnoea index (AHI) ≥10 events/h. RESULTS: In the model development phase, 25 primary care practitioners studied 315 patients in whom they suspected OSA, of which 57% had AHI≥10 and 22% had AHI≥30. Published OSA questionnaires provided low to moderate prediction of OSA (area under the curve [AUC] 0.53-0.73). The nasal flow monitor alone yielded high accuracy for predicting OSA with AUC of 0.87. Sensitivity was 0.87 and specificity 0.77 at a threshold respiratory event index (REI) of 18 events/h. A model adding age, gender, symptoms and BMI to the nasal flow monitor REI only modestly improved OSA prediction (AUC 0.89), with similar AUC (0.88) confirmed in the validation population of 114 patients. CONCLUSION: Sleep apnoea can be diagnosed in the primary care setting with a combination of clinical judgement and portable monitor test outcomes.