Sustained improvement in mild obstructive sleep apnea after a diet- and physical activity-based lifestyle intervention: postinterventional follow-up

Sleep apnoea, gut dysbiosis and cognitive dysfunction

Sleep disorders are becoming increasingly common, and their distinct effects on physical and mental health require elaborate investigation. Gut dysbiosis (GD) has been reported in sleep-related disorders, but sleep apnoea is of particular significance because of its higher prevalence and chronicity. Cumulative evidence has suggested a link between sleep apnoea and GD. This review highlights the gut-brain communication axis that is mediated via commensal microbes and various microbiota-derived metabolites (e.g. short-chain fatty acids, lipopolysaccharide and trimethyl amine N-oxide), neurotransmitters (e.g. γ-aminobutyric acid, serotonin, glutamate and dopamine), immune cells and inflammatory mediators, as well as the vagus nerve and hypothalamic-pituitary-adrenal axis. This review also discusses the pathological role underpinning GD and altered gut bacterial populations in sleep apnoea and its related comorbid conditions, particularly cognitive dysfunction. In addition, the review examines the preclinical and clinical evidence, which suggests that prebiotics and probiotics may potentially be beneficial in sleep apnoea and its comorbidities through restoration of eubiosis or gut microbial homeostasis that regulates neural, metabolic and immune responses, as well as physiological barrier integrity via the gut-brain axis.

Sustained improvements in the cardiometabolic profile of patients with obstructive sleep apnea after a weight-loss Mediterranean diet/lifestyle intervention: 12-month follow-up (6 months post-intervention) of the "MIMOSA" randomized clinical trial

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) and the metabolic syndrome (MS) frequently coexist and lead to increased cardiometabolic morbidity. We aimed to explore the long-term cardiometabolic benefits of a weight-loss Mediterranean diet/lifestyle intervention in OSA.

METHODS AND RESULTS

As many as 180 adults with overweight/obesity and polysomnography-diagnosed moderate-to-severe OSA were randomized to a standard care (SCG, n = 62), a Mediterranean diet (MDG, n = 59) or a Mediterranean lifestyle group (MLG, n = 59). All groups were prescribed with continuous positive airway pressure (CPAP), while intervention arms (MDG/MLG) additionally participated in a 6-month weight-loss intervention based on the Mediterranean diet/lifestyle. Cardiometabolic parameters were evaluated at baseline and 12 months (6 months post-intervention). Data were analyzed using the intention-to-treat method, and 12-month between-group differences were explored while adjusting for age, sex, baseline status and CPAP use. Compared to the SCG, intervention arms exhibited lower insulin, triglycerides and high-sensitivity C-reactive protein, and higher high-density lipoprotein cholesterol; the MDG also exhibited lower diastolic blood pressure, while the MLG exhibited lower glucose and systolic blood pressure (all P < 0.050). The relative risk (95% confidence interval) of MS was 0.60 (0.36, 0.99) in the MDG versus the SCG, 0.33 (0.20, 0.55) in the MLG versus the SCG and 0.55 (0.32, 0.93) in the MLG versus the MDG. The risk of MS remained lower in the MLG versus the other study groups (both P < 0.050) after additional adjustment for body weight change.

CONCLUSION

Cardiometabolic benefits of a 6-month healthy dietary/lifestyle intervention are sustainable 6 months post-intervention in OSA.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02515357, August 4, 2015.

Effect of yoga-based lifestyle and dietary modification in overweight individuals with sleep apnea: A randomized controlled trial (ELISA)

BACKGROUND

Obesity is recognised as an important risk factor for obstructive sleep apnea (OSA), with obese individuals at a four times higher risk of being diagnosed with the syndrome. Treating obesity with lifestyle modification is associated with a reduction in the severity of obstructive sleep apnea. Yoga comprises lifestyle modification that includes asana (postures), pranayama (breathing techniques), dhyana (meditation) and guideline principles for healthy living (Yama and Niyama). There is a scarcity of data to evaluate the effect of yoga on OSA. This study was conducted to evaluate the efficacy of Yoga based lifestyle modification on OSA.

METHODS

Consenting obese patients (BMI >23) diagnosed with obstructive sleep apnea (OSA) (AHI>5) on Polysomnography (PSG) were enrolled. Eligible patients were randomized into two groups. The control group received counselling for dietary modification (staple Indian) with regular exercise and the active intervention group received Yoga intervention as treatment (OSA module) in addition to similar dietary modification and regular exercise counselling. Polysomnography (PSG) was conducted at baseline and one year follow-up. All patients were evaluated at baseline, six months, and one year for compliance and anthropometric parameters. Additional assessment with Hamilton scales for depression and anxiety, SF-36, and the Pittsburgh sleep quality index was also conducted.

RESULTS

A total of 37 eligible patients (19 in the control group and 18 in the yoga group) were recruited for the study. The age [45.73 ± 10.71 vs. 46.22 ± 9.39 years, p = 0.88] and gender [15(78.95%) vs. 12(66.67%), p = 0.48 (males)] distribution was similar in both groups. After adjusting for age and gender, the percentage reduction in weight between the two groups did not reach statistical significance at one year. There was no significant difference in mean AHI between the two groups at one year. However, the number of patients with more than 40% AHI reduction [2/19 (10.52%) vs 8/18 (44.44%), p = 0.02] was significantly higher in the yoga group. Additionally, within the groups, the mean AHI at one year was significantly reduced in the yoga group [51.2 ± 28.0 to 36.8 ± 21.0/hour, p = 0.003], while no significant change was found in the control group [47.2 ± 23 to 38.8 ± 19.9/hour, p = 0.08].

CONCLUSIONS

Lifestyle alteration using Yoga intervention and modification of staple Indian diet may be effective in reducing OSA severity among obese patients.

CTRI NUMBER

CTRI/2017/05/008462.

High quality and anti-inflammatory diets and a healthy lifestyle are associated with lower sleep apnea risk

STUDY OBJECTIVES

Most studies on diet and sleep apnea focus on calorie restriction. Here we investigate potential associations between dietary quality [healthy eating index (HEI), dietary inflammatory index (DII)] and overall healthy lifestyle with sleep apnea risk.

METHODS

National Health and Nutrition Examination Survey data (waves 2005-2008, and 2015-2018; N=14,210) were used to determine HEI, DII and their quintiles, with the fifth quintile indicating highest adherence to each dietary construct. A healthy lifestyle score was determined using diet, smoking, alcohol intake and physical activity level. STOP-BANG questionnaire was used to define sleep apnea risk. Generalized linear regression models with binomial family and logit link were used to investigate potential associations. The models were adjusted for socioeconomic status, lifestyle factors and chronic conditions.

RESULTS

Prevalence of high sleep apnea risk was 25.1%. Higher DII was positively associated with sleep apnea (odds ratio (OR)_{Q5 vs. Q1}=1.55; 95% CI: 1.24-1.94; p for trend <0.001) whereas higher HEI was associated with reduced sleep apnea risk (OR_{Q5 VS. Q1}=0.72: 0.59-0.88; p for trend=0.007). Higher healthy lifestyle score was also associated with decreased odds of sleep apnea (p for trend <0.001). There was a significant interaction between healthy lifestyle and sex with sleep apnea risk (p for interaction=0.049) whereby females with higher healthy lifestyle scores had lower risk of sleep apnea versus males.

CONCLUSIONS

Higher quality and anti-inflammatory diets and a healthier overall lifestyle are associated with lower sleep apnea risk. These findings underline the importance of strategies to improve overall diet quality and promote healthy behavior, not just calorie restriction, to reduce sleep apnea risk.

Physical activity, sedentary behaviour and incidence of obstructive sleep apnoea in three prospective US cohorts

BACKGROUND

Reduced physical activity and increased sedentary behaviour may independently contribute to the development of obstructive sleep apnoea (OSA) through increased adiposity, inflammation, insulin resistance and body fluid retention. However, epidemiological evidence remains sparse and is primarily limited to cross-sectional studies.

METHODS

We prospectively followed 50 332 women from the Nurses' Health Study (2002-2012), 68 265 women from the Nurses' Health Study II (1995-2013) and 19 320 men from the Health Professionals Follow-up Study (1996-2012). Recreational physical activity (quantified by metabolic equivalent of task (MET)-h per week) and sitting time spent watching TV and at work/away from home were assessed by questionnaires every 2-4 years. Physician-diagnosed OSA was identified by validated self-report. Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals for OSA incidence associated with physical activity and sedentary behaviour.

RESULTS

During 2 004 663 person-years of follow-up, we documented 8733 incident OSA cases. After adjusting for potential confounders, the pooled HR for OSA comparing participants with ≥36.0 versus <6.0 MET-h per week of physical activity was 0.46 (95% CI 0.43-0.50; p_trend<0.001). Compared with participants spending <4.0 h per week sitting watching TV, the multivariable-adjusted HR was 1.78 (95% CI 1.60-1.98) for participants spending ≥28.0 h per week (p_trend<0.001). The comparable HR was 1.49 (95% CI 1.38-1.62) for sitting hours at work/away from home (p_trend<0.001). With additional adjustment for several metabolic factors, including body mass index and waist circumference, the associations with physical activity and sitting hours at work/away from home were attenuated but remained significant (p_trend<0.001), whereas the association with sitting hours watching TV was no longer statistically significant (p_trend=0.18).

CONCLUSIONS

Higher levels of physical activity and fewer sedentary hours were associated with lower OSA incidence. The potential mediating role of metabolic factors in the association between sedentary behaviour and OSA incidence may depend on the type of sedentary behaviour. Our results suggest that promoting an active lifestyle may reduce OSA incidence.

The treatment of mild OSA with CPAP or mandibular advancement device and the effect on blood pressure and endothelial function after one year of treatment

STUDY OBJECTIVES

To evaluate and compare the effects of continuous positive airway pressure (CPAP), use of a mandibular advancement device (MAD), and no treatment on 24-hour ambulatory blood pressure monitoring and peripheral arterial tonometry at 6 and 12 months follow-up in individuals with mild obstructive sleep apnea (OSA), and in a subgroup who had an apnea-hypopnea index of < 5 events/h and adherence of ≥ 4 hours per night (effective-treatment subgroups).

METHODS

The inclusion criteria were individuals with mild obstructive sleep apnea, any sex, age between 18 and 65 years, and a body mass index of ≤ 35 kg/m². Patients were randomized into CPAP, MAD, and no-treatment groups. The evaluations included physical examination, full polysomnography, 24-hour ambulatory blood pressure monitoring, and peripheral arterial tonometry at baseline and after 6 and 12 months. A generalized linear mixed model was used for comparisons.

RESULTS

The CPAP and MAD groups had lower apnea-hypopnea indexes than the control group at 6 and 12 months, and the CPAP group had higher blood oxygen levels (SpO₂) than the MAD group. The MAD group had more hours of treatment per night and better adaptation to treatment than the CPAP group (MAD: 5.7 ± 2.7 h/night; CPAP: 3.8 ± 3.4 h/night; MAD: 16% did not adapt; CPAP: 42% did not adapt). No differences were found in the total sample and effective treatment in relation to peripheral arterial tonometry or 24-hour ambulatory blood pressure monitoring outcomes.

CONCLUSIONS

Treatment of mild obstructive sleep apnea with CPAP or MAD did not improve blood pressure or endothelial function after 1 year, even in patients with effective treatment.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Continuous Positive Airway Pressure and Oral Appliances Treatments in Mild Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT01461486; Identifier: NCT01461486.

Comparison of the Effects of the Somatotype on the Physical Activity, Kinesiophobia, and Fatigue Levels of Obstructive Sleep Apnea Syndrome Patients and Healthy Individuals

Background:

We aimed to compare the physical activity, kinesiophobia, and fatigue levels of obstructive sleep apnea syndrome (OSAS) patients and healthy individuals in terms their somatotypes.

Methods:

A total of 165 individuals were enrolled referred to the Department of Chest Diseases Sleep Disorders Center Outpatient Clinic of Inonu University, Malatya, Turkey in 2018. The somatotype analysis was conducted using the Heath-Carter method, the fatigue level was assessed using the Functional Assessment of Chronic Illness Therapy (FACIT) fatigue scale, the kinesiophobia level was assessed using the Tampa Scale for Kinesiophobia (TSK), and the physical activity level was assessed using the International Physical Activity Questionnaire (IPAQ).

Results:

The results of the somatotype analysis revealed 3 different somatotypes in the healthy individuals and the OSAS patients’ mesomorph endomorph, endomorphic mesomorph, and mesomorphic endomorph. When comparing the somatotypes of the healthy individuals and the OSAS patients, statistically significant differences were found in the FACIT scores of the mesomorph endomorphs, the IPAQ and FACIT scores of the endomorphic mesomorphs, and the TSK and FACIT scores of the mesomorphic endomorphs (P<0.05).

Conclusion:

In all three somatotypes of the OSAS patients, the fatigue index scores were higher when compared to those of the healthy individuals. Moreover, when compared with the healthy individuals, the physical activity levels of the endomorphic mesomorphs with OSAS were low, while the kinesiophobia scores of the mesomorphic endomorphs with OSAS were high. Based on the results of this study, in OSAS patients, the endomorphic mesomorph somatotype could be a risk factor for reduced physical activity, while the mesomorphic endomorph somatotype could be a risk factor for increased kinesiophobia.

Body Mass Index Reduction and Selected Cardiometabolic Risk Factors in Obstructive Sleep Apnea: Meta-Analysis

Although clinical studies have been carried out on the effects of weight reduction in sleep apnea patients, no direct link has been shown between weight reduction and changes in cardio-metabolic risk factors. We aimed to analyze changes in the apnea–hypopnea index and selected cardio-metabolic parameters (total cholesterol, triglycerides, glucose, insulin, blood pressure) in relation to the reduction in body mass index in obstructive sleep apnea patients. Medline, Web of Science and Cochrane databases were searched to combine results from individual studies in a single meta-analysis. We identified 333 relevant articles, from which 30 papers were assigned for full-text review, and finally 10 (seven randomized controlled trials and three nonrandomized studies) were included for data analysis. One unit of body mass index reduction was found to significantly influence changes in the apnea–hypopnea index (−2.83/h; 95% CI: −4.24, −1.41), total cholesterol (−0.12 mmol/L; 95% CI: −0.22, −0.01), triglycerides (−0.24 mmol/L; 95% CI: −0.46, −0.02), fasting insulin (−7.3 pmol/L; 95% CI: −11.5, −3.1), systolic (−1.86 mmHg; 95% CI: −3.57, −0.15) and diastolic blood pressure (−2.07 mmHg; 95% CI: −3.79, −0.35). Practical application of lifestyle modification resulting in the reduction of one unit of body mass index gives meaningful changes in selected cardio-metabolic risk factors in obstructive sleep apnea patients.

Effects of Weight Loss on Obstructive Sleep Apnea Severity. Ten-Year Results of the Sleep AHEAD Study

Rationale: Weight loss is recommended to treat obstructive sleep apnea (OSA).Objectives: To determine whether the initial benefit of intensive lifestyle intervention (ILI) for weight loss on OSA severity is maintained at 10 years.Methods: Ten-year follow-up polysomnograms of 134 of 264 adults in Sleep AHEAD (Action for Health in Diabetes) with overweight/obesity, type 2 diabetes mellitus, and OSA were randomized to ILI for weight loss or diabetes support and education (DSE).Measurements and Main Results: Change in apnea-hypopnea index (AHI) was measured. Mean ± SE weight losses of ILI participants of 10.7 ± 0.7, 7.4 ± 0.7, 5.1 ± 0.7, and 7.1 ± 0.8 kg at 1, 2, 4, and 10 years, respectively, were significantly greater than the 1-kg weight loss at 1, 2, and 4 years and 3.5 ± 0.8 kg weight loss at 10 years for the DSE group (P values ≤ 0.0001). AHI was lower with ILI than DSE by 9.7, 8.0, and 7.9 events/h at 1, 2, and 4 years, respectively (P values ≤ 0.0004), and 4.0 events/h at 10 years (P = 0.109). Change in AHI over time was related to amount of weight loss, baseline AHI, visit year (P values < 0.0001), and intervention independent of weight change (P = 0.01). OSA remission at 10 years was more common with ILI (34.4%) than DSE (22.2%).Conclusions: Participants with OSA and type 2 diabetes mellitus receiving ILI for weight loss had reduced OSA severity at 10 years. No difference in OSA severity was present between ILI and DSE groups at 10 years. Improvement in OSA severity over the 10-year period with ILI was related to change in body weight, baseline AHI, and intervention independent of weight change.

Sleep Disordered Breathing: An Epidemiological Study among Albanian Children and Adolescents

Sleep Disordered Breathing (SDB) comprises a group of diseases characterized by alterations in the frequency and/or depth of breathing during sleep. The aim of this study was to investigate the frequency of SDB in a group of Albanian children and adolescents and to describe its social, physiological, psychological, sleep-related, and anthropometric risk factors, in relation to the sociodemographic situation. A total of 6087 participants (mean age: 10.42 years, range: 6 to 15 years, 52.3% females and 47.7% males) attending public schools all over Albania took part in the cross-sectional study. On a sample of 6087 questionnaires distributed, 4702 (77.25% of the original sample) were returned and included in the study. High risk status for SDB was assessed using the Paediatric Sleep Questionnaire (PSQ). The prevalence of SDB was 7.9%. No statistically significant difference was found for gender at high risk for SBD. Compared to participants living in urban aeras (7.3%), participants living in rural areas (10.4%) reported significantly higher SDB prevalence rates. No other significant correlations were detected between the high-risk subjects and the age. The prevalence of the subjects at high risk of SBD obese participants (20.8%) was statistically higher than among nonobese ones (6.3%). SDB is highly prevalent in Albanian growing population and further prevalence studies are recommended.

Mandibular advancement device therapy for obstructive sleep apnea: A longitudinal study among patients treated in community dental care in Finland - Potential for the precision medicine approach

Objective: Obstructive sleep apnea (OSA) is an increasing health problem worldwide. The aim was to evaluate long-term mandibular advancement device (MAD) therapy outcomes in community dental care among OSA patients in Finland.Methods: In all, 142 (77.2%) respondents of a questionnaire, with recently initiated treatment, were included in the study in 2010. Follow-up questionnaires were mailed in 2012 and 2017.Results: Problems occurred with the device long-term. Orofacial pain was reported more often in 2012 than in 2010 (p < 0.01). Snoring (p < 0.01) and tiredness (p < 0.05) were also significantly increased. In 2017, 50 subjects were still continuing with MAD, 20 of them as a single treatment modality. Treatment modalities in combination with MAD were CPAP, nutrition counseling, and position treatment.Discussion: Long-term MAD treatment may lead to a changing treatment-mix and set-backs. This may not only be a treatment adherence issue but also a lack of precision medicine approach regarding OSA.

Effectiveness of an intensive weight-loss program for severe OSA in patients undergoing CPAP treatment: a randomized controlled trial

STUDY OBJECTIVES

To determine whether an intensive weight-loss program (IWLP) is effective for reducing weight, the severity of obstructive sleep apnea (OSA), and metabolic variables in patients with obesity and severe OSA undergoing continuous positive airway pressure treatment.

METHODS

Forty-two patients were randomized to the control (CG, n = 20) or the intervention group (IG, n = 22), who followed a 12-month IWLP. The primary outcome was a reduction in the apnea-hypopnea index (AHI) as measured at 3 and 12 months by full polysomnography. Metabolic variables, blood pressure, body fat composition by bioimpedance, carotid intima media thickness, and visceral fat by computed tomography were also assessed.

RESULTS

Mean age was 49 (6.7) years, body mass index 35 (2.7) kg/m², and AHI 69 (20) events/h. Weight reduction was higher for the IG than the CG at 3 and 12 months, -10.5 versus -2.3 kg (P < .001), and -8.2 versus -0.1 kg (P < .001), respectively, as was loss of visceral fat at 12 months. AHI decreased more in the IG at 3 months (-23.72 versus -9 events/h) but the difference was not significant at 12 months, though 28% of patients from the IG had an AHI < 30 events/h compared to none in the CG (P = .046). At 12 months, the IG showed a reduction in C-reactive protein (P = .013), glycated hemoglobin (P = .031) and an increase in high density lipoprotein cholesterol (P = .027).

CONCLUSIONS

An IWLP in patients with obesity and severe OSA is effective for reducing weight and OSA severity. It also results in an improvement in lipid profiles, glycemic control, and inflammatory markers.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Effectiveness of an Intensive Weight Loss Program for Obstructive Sleep Apnea Syndrome (OSAS) Treatment; Identifier: NCT02832414; URL: https://clinicaltrials.gov/ct2/show/record/NCT02832414.

Effect of Weight Loss on Upper Airway Anatomy and the Apnea-Hypopnea Index. The Importance of Tongue Fat

Rationale: Obesity is the primary risk factor for obstructive sleep apnea (OSA). Tongue fat is increased in obese persons with OSA, and may explain the relationship between obesity and OSA. Weight loss improves OSA, but the mechanism is unknown.Objectives: To determine the effect of weight loss on upper airway anatomy in subjects with obesity and OSA. We hypothesized that weight loss would decrease soft tissue volumes and tongue fat, and that these changes would correlate with reductions in apnea-hypopnea index (AHI).Methods: A total of 67 individuals with obesity and OSA (AHI ≥ 10 events/h) underwent a sleep study and upper airway and abdominal magnetic resonance imaging before and after a weight loss intervention (intensive lifestyle modification or bariatric surgery). Airway sizes and soft tissue, tongue fat, and abdominal fat volumes were quantified. Associations between weight loss and changes in these structures, and relationships to AHI changes, were examined.Measurements and Main Results: Weight loss was significantly associated with reductions in tongue fat and pterygoid and total lateral wall volumes. Reductions in tongue fat were strongly correlated with reductions in AHI (Pearson's rho = 0.62, P < 0.0001); results remained after controlling for weight loss (Pearson's rho = 0.36, P = 0.014). Reduction in tongue fat volume was the primary upper airway mediator of the relationship between weight loss and AHI improvement.Conclusions: Weight loss reduced volumes of several upper airway soft tissues in subjects with obesity and OSA. Improved AHI with weight loss was mediated by reductions in tongue fat. New treatments that reduce tongue fat should be considered for patients with OSA.

Associations of Inflammation, Physical Activity, and Sleep in a Diverse Population of Women

Background: Cardiovascular disease (CVD) is the leading cause of mortality in United States with a recent rise seen in young adults, particularly women. Systemic inflammation, physical activity, and sleep are each individually linked to CVD risk. Whether there is an interaction of these variables, however, is unclear. We evaluated physical activity and sleep among racially ethnically diverse women, ages 20-79 years, to assess associations with systemic inflammation. Methods: We performed a cross-sectional study of 506 women (61% racial/ethnic minority; mean (standard deviation [SD]) age = 37 [15.7] years, body mass index 26.0 [5.7] kg/m²) enrolled in the American Heart Association (AHA) Go Red for Women Strategically Focused Research Network at Columbia University Irving Medical Center (CUIMC). Inflammation, assessed by C-reactive protein (CRP), was analyzed in the Biomarkers Core Laboratory at CUIMC. Physical activity and sleep were assessed using validated questionnaires. Multivariable models adjusted for demographic and clinical confounders were used to evaluate associations between CRP, physical activity, and sleep. Results: Mean (SD) physical activity was 282 (557.2) minutes/week, and mean (SD) sleep duration was 6.75 (1.24) hours/night. Mean CRP was 2.08 (3.56), and 17% of participants were categorized as high risk for obstructive sleep apnea (OSA). Participants who slept <6 hours/night were less likely to be physically active ≥150 minutes/week (odds ratios, ORs [95% confidence interval, CI]: 0.53 [0.33-0.84]). This association was nonsignificant after adjustment. High risk of OSA was associated with CRP ≥2 mg/L (OR [95% CI]: 1.91 [1.11-3.30]) following adjustment. Stratification by race/ethnicity showed that high risk of OSA was associated with CRP ≥2 mg/L among racial/ethnic minorities but not white women (OR [95% CI]: 2.75 [1.43-5.30] vs. 0.94 [0.31-2.88]). Conclusion: High risk of OSA and elevated CRP was significantly associated in women, particularly minority women. Both play a role in CVD, highlighting potential causes for the increased risk of CVD in younger women.

Effects of fasting intervention regulating anthropometric and metabolic parameters in subjects with overweight or obesity: a systematic review and meta-analysis

Previous studies have shown that fasting produces a potential effect in the prevention and treatment of many diseases.

Weight loss and lifestyle interventions for obstructive sleep apnoea in adults: Systematic review and meta-analysis

Lifestyle interventions addressing diet, exercise-training, sleep hygiene, and/or tobacco/alcohol cessation are recommended in the management of obstructive sleep apnoea (OSA). Yet their effectiveness on this condition still requires further research. This systematic review and meta-analysis was aimed at establishing (a) the effectiveness of lifestyle interventions on apnoea-hypopnoea index (AHI), oxygen desaturation index (ODI), excessive daytime sleepiness (EDS), and secondary OSA measures among adults, and (b) which intervention characteristics may drive the greatest improvements. A systematic search of studies was conducted using CINAHL, ProQuest, Psicodoc, Scopus, and Web of Science, from inception to April 2018. Standardized mean differences were calculated using the inverse variance method and random-effects models. The meta-analyses of 13 randomized controlled trials and 22 uncontrolled before-and-after studies (1420 participants) revealed significant reductions on AHI (d = -0.61 and -0.46, respectively), ODI (d = -0.61 and -0.46) and EDS (d = -0.41 and -0.49). Secondary OSA outcomes were also improved after interventions. However, effectiveness of interventions differed depending on their components, OSA severity, and gender. Thus, until future research further supports the differential effectiveness among lifestyle interventions on OSA, those addressing weight loss through diet and exercise-training may be the most effective treatments for male patients with moderate-severe OSA.

Prevalence and risk factors of people at-risk of obstructive sleep apnea in a rural community of Odisha, India: a community based cross-sectional study

BACKGROUND

Obstructive sleep apnea (OSA) is a progressive sleep disordered breathing condition characterized by repeated episodes of upper airway collapse during sleep. Despite being the most common sleep apnea, it often remains undiagnosed and untreated, especially in rural communities. There is a paucity of literature estimating the prevalence of the disease and associated risk factors from the rural population of Odisha.

METHODS

It is a cross-sectional study that was conducted in a rural community of Odisha, India to find out the prevalence of people living with the risk of OSA. Multi-staged sampling was done. Participants were evaluated using the Berlin questionnaire (BQ) after obtaining informed consent. Data were analyzed using SPSS with the significance level set at 95%. Univariate and multivariate analysis was done to evaluate the risk factors associated with the condition.

RESULTS

Out of 200 community dwellers surveyed using the BQ, 25% had a high likelihood of OSA. Among these high risk subjects, snoring was reported by 70%, excessive daytime sleepiness by 50%. Out of those who were at risk of OSA, 28% were smokers and 48% reported alcohol use. The associated risk factors were age >35 years (OR = 4.5, 95% CI = 1.4-13.8, p < 0.05), BMI ≥ 25 kg/m² (aOR = 3.5, 95% CI = 1.2- 10.5, p < 0.05), alcoholism (aOR = 4.5, 95% CI = 1.8-11.1, p = 0.001), and hypertension (aOR = 11.5, 95% CI = 4.7-28, p < 0.001). The prevalence was not affected by the type of diet (vegetarian vs non-vegetarian), use of tobacco or tea consumption.

CONCLUSION

OSA is highly prevalent in the rural community of Odisha. Independent risk factors associated with such subjects were obesity, regular alcohol consumption, and hypertension. Further prevalence studies are recommended.

Effects of obesity therapies on sleep disorders

Obesity is a significant risk factor for obstructive sleep apnea syndrome (OSAS), and has also been linked to reductions in sleep quality and quantity. Weight loss has been shown to be an effective treatment for improving OSAS; however, there is a high degree of variability in improvements of OSAS in response to weight loss. There are three modalities of obesity therapies: 1) lifestyle modification, which includes changes in dietary intake and physical activity, along with behavioral interventions; 2) pharmacologic agents; and 3) bariatric surgery. Individuals have a highly variable response to the various obesity interventions, and maintenance of weight loss can be especially challenging. These factors influence the effect of weight loss on sleep disorders. There is still a need for large, well-controlled studies examining short- and long-term efficacy of weight loss modalities and their impact on long-term treatment of OSAS and other sleep parameters, particularly in youth. Nonetheless, given our current knowledge, weight reduction should always be encouraged for people coping with obesity, OSAS, and/or sleep disruptions and resources identified to assist patients in choosing a weight loss approach that will benefit them the most.

Maintenance diets following rapid weight loss in obstructive sleep apnea: a pilot 1-year clinical trial

Very low energy diets (VLED) appear to be the most efficacious dietary-based obesity reduction treatments in obstructive sleep apnea (OSA); however, effective weight loss maintenance strategies remain untested in this condition. Our study aimed to assess the feasibility, tolerability and efficacy of two common maintenance diets during a 10-month follow-up period after rapid weight loss using a 2-month VLED. In this two-arm, single-centre, open-label pilot trial, obese adult OSA patients received a 2-month VLED before being allocated to either the Australian Guide to Healthy Eating diet (AGHE) or a low glycaemic index high-protein diet (LGHP). Outcomes were measured at 0, 2 and 12 months. We recruited 44 patients [113.1 ± 19.5 kg, body mass index (BMI): 37.2 ± 5.6 kg m^-2 , 49.3 ± 9.2 years, 12 females]. Twenty-four patients were on continuous positive airway pressure (CPAP) or mandibular advancement splint (MAS) therapy for OSA. Forty-two patients completed the VLED. The primary outcome of waist circumference was reduced by 10.6 cm at 2 months [95% confidence interval (CI): 9.2-12.1], and patients lost 12.9 kg in total weight (95% CI: 11.2-14.6). There were small but statistically significant regains in waist circumference between 2 and 12 months [AGHE = 3.5 cm (1.3-5.6) and LGHP = 2.8 cm (0.6-5.0]. Other outcomes followed a similar pattern of change. After weight loss with a 2-month VLED in obese patients with OSA, a structured weight loss maintenance programme incorporating commonly used diets was feasible, tolerable and efficacious for 10 months. This programme may be deployed easily within sleep clinics; however, future research should first test its translation within general clinical practice.

Diet and exercise in the management of obstructive sleep apnoea and cardiovascular disease risk

Obstructive sleep apnoea (OSA) is associated with increased cardiovascular disease (CVD) morbidity and mortality. It is accepted that OSA and obesity commonly coexist. The American Academy of Sleep Medicine recommends dietary-induced weight loss and exercise as lifestyle treatment options for OSA. However, most clinical trials upon which this recommendation is based have focused on establishing the effectiveness of calorie-restricted, often low-fat diets for improving OSA severity, whereas less attention has been given to the means through which weight loss is achieved (e.g. altered dietary quality) or whether diet or exercise mediates the associations between reduced weight, improved OSA severity and the CVD substrate. The current evidence suggests that the benefits of a low-carbohydrate or Mediterranean diet in overweight and obese individuals go beyond the recognised benefits of weight reduction. In addition, exercise has an independent protective effect on vascular health, which may counter the increased oxidative stress, inflammation and sympathetic activation that occur in OSA patients. This review aims to expand our understanding of the effects of diet and exercise on OSA and associated CVD complications, and sets the stage for continued research designed to explore optimal lifestyle strategies for reducing the CVD burden in OSA patients.

An Official American Thoracic Society Research Statement: Impact of Mild Obstructive Sleep Apnea in Adults

BACKGROUND

Mild obstructive sleep apnea (OSA) is a highly prevalent disorder in adults; however, whether mild OSA has significant neurocognitive and cardiovascular complications is uncertain.

OBJECTIVES

The specific goals of this Research Statement are to appraise the evidence regarding whether long-term adverse neurocognitive and cardiovascular outcomes are attributable to mild OSA in adults, evaluate whether or not treatment of mild OSA is effective at preventing or reducing these adverse neurocognitive and cardiovascular outcomes, delineate the key research gaps, and provide direction for future research agendas.

METHODS

Literature searches from multiple reference databases were performed using medical subject headings and text words for OSA in adults as well as by hand searches. Pragmatic systematic reviews of the relevant body of evidence were performed.

RESULTS

Studies were incongruent in their definitions of "mild" OSA. Data were inconsistent regarding the relationship between mild OSA and daytime sleepiness. However, treatment of mild OSA may improve sleepiness in patients who are sleepy at baseline and improve quality of life. There is limited or inconsistent evidence pertaining to the impact of therapy of mild OSA on neurocognition, mood, vehicle accidents, cardiovascular events, stroke, and arrhythmias.

CONCLUSIONS

There is evidence that treatment of mild OSA in individuals who demonstrate subjective sleepiness may be beneficial. Treatment may also improve quality of life. Future research agendas should focus on clarifying the effect of mild OSA and impact of effective treatment on other neurocognitive and cardiovascular endpoints as detailed in the document.

Clinical effectiveness of very-low-energy diets in the management of weight loss: a systematic review and meta-analysis of randomized controlled trials

Guidelines suggest that very-low-energy diets (VLEDs) should be used to treat obesity only when rapid weight loss is clinically indicated because of concerns about rapid weight regain. Literature databases were searched from inception to November 2014. Randomized trials were included where the intervention included a VLED and the comparator was no intervention or an intervention that could be given in a general medical setting in adults that were overweight. Two reviewers characterized the population, intervention, control groups, outcomes and appraised quality. The primary outcome was weight change at 12 months from baseline. Compared with a behavioural programme alone, VLEDs combined with a behavioural programme achieved -3.9 kg [95% confidence interval (CI) -6.7 to -1.1] at 1 year. The difference at 24 months was -1.4 kg (95%CI -2.6 to -0.2) and at 38-60 months was -1.3 kg (95%CI -2.9 to 0.2). Nineteen per cent of the VLED group discontinued treatment prematurely compared with 20% of the comparator groups, relative risk 0.96 (0.56 to 1.66). One serious adverse event, hospitalization with cholecystitis, was reported in the VLED group and none in the comparator group. Very-low-energy diets with behavioural programmes achieve greater long-term weight loss than behavioural programmes alone, appear tolerable and lead to few adverse events suggesting they could be more widely used than current guidelines suggest.

Bariatric Surgery or Non-Surgical Weight Loss for Obstructive Sleep Apnoea? A Systematic Review and Comparison of Meta-analyses

BACKGROUND

Obstructive sleep apnoea (OSA) is a well-recognised complication of obesity. Non-surgical weight loss (medical, behavioural and lifestyle interventions) may improve OSA outcomes, although long-term weight control remains challenging. Bariatric surgery offers a successful strategy for long-term weight loss and symptom resolution.

OBJECTIVES

To comparatively appraise bariatric surgery vs. non-surgical weight loss interventions in OSA treatment utilising body mass index (BMI) and apnoea-hypopnoea index (AHI) as objective measures of weight loss and apnoea severity.

METHODS

A systematic literature review revealed 19 surgical (n = 525) and 20 non-surgical (n = 825) studies reporting the primary endpoints of BMI and AHI before and after intervention. Data were meta-analysed using random effects modelling. Subgroup analysis, quality scoring and risk of bias were assessed.

RESULTS

Surgical patients had a mean pre-intervention BMI of 51.3 and achieved a significant 14 kg/m(2) weighted decrease in BMI (95%CI [11.91, 16.44]), with a 29/h weighted decrease in AHI (95%CI [22.41, 36.74]). Non-surgical patients had a mean pre-intervention BMI of 38.3 and achieved a significant weighted decrease in BMI of 3.1 kg/m(2) (95%CI [2.42, 3.79]), with a weighted decrease in AHI of 11/h (95%CI [7.81, 14.98]). Heterogeneity was high across all outcomes.

CONCLUSIONS

Both bariatric surgery and non-surgical weight loss may have significant beneficial effects on OSA through BMI and AHI reduction. However, bariatric surgery may offer markedly greater improvement in BMI and AHI than non-surgical alternatives. Future studies must address the lack of randomised controlled and comparative trials in order to confirm the exact relationship between metabolic surgery and non-surgical weight loss interventions in OSA resolution.

The Effect of Changes in Cardiorespiratory Fitness and Weight on Obstructive Sleep Apnea Severity in Overweight Adults with Type 2 Diabetes

STUDY OBJECTIVES

To examine the effect of changes in cardiorespiratory fitness on obstructive sleep apnea (OSA) severity prior to and following adjustment for changes in weight over the course of a 4-y weight loss intervention.

METHODS

As secondary analyses of a randomized controlled trial, 263 overweight/obese adults with type 2 diabetes and OSA participated in an intensive lifestyle intervention or education control condition. Measures of OSA severity, cardiorespiratory fitness, and body weight were obtained at baseline, year 1, and year 4. Change in the apnea-hypopnea index (AHI) served as the primary outcome. The percentage change in fitness (submaximal metabolic equivalents [METs]) and change in weight (kg) were the primary independent variables. Primary analyses collapsed intervention conditions with statistical adjustment for treatment group and baseline METs, weight, and AHI among other relevant covariates.

RESULTS

At baseline, greater METs were associated with lower AHI (B [SE] = -1.48 [0.71], P = 0.038), but this relationship no longer existed (B [SE] = -0.24 [0.73], P = 0.75) after adjustment for weight (B [SE] = 0.31 [0.07], P < 0.0001). Fitness significantly increased at year 1 (+16.53 ± 28.71% relative to baseline), but returned to near-baseline levels by year 4 (+1.81 ± 24.48%). In mixed-model analyses of AHI change over time without consideration of weight change, increased fitness at year 1 (B [SE] = -0.15 [0.04], P < 0.0001), but not at year 4 (B [SE] = 0.04 [0.05], P = 0.48), was associated with AHI reduction. However, with weight change in the model, greater weight loss was associated with AHI reduction at years 1 and 4 (B [SE] = 0.81 [0.16] and 0.60 [0.16], both P < 0.0001), rendering the association between fitness and AHI change at year 1 nonsignificant (B [SE] = -0.04 [0.04], P = 0.31).

CONCLUSIONS

Among overweight/obese adults with type 2 diabetes, fitness change did not influence OSA severity change when weight change was taken into account.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identification number NCT00194259.

Comorbidity of diabetes and obstructive sleep apnea in hospitalized patients

Obstructive sleep apnea (OSA) and type 2 diabetes are two morbidities commonly encountered in the hospitalized setting. Both diseases will present with an array of complications if not managed in a timely, competent manner. However, a growing body of evidence suggests a link between these two pathologies. It is our hope that through careful review of the literature, we may generate heightened awareness of the OSA/diabetes comorbidity. Through better understanding of these conditions and their interactions, we may insure efficient management in the clinical setting and prevent exacerbation of common complications.

Mild obstructive sleep apnea does not modulate baroreflex sensitivity in adult patients

BACKGROUND

Obstructive sleep apnea (OSA) is a chronic and progressive disease. OSA is associated with increased cardiovascular morbidity and mortality, the risk being more frequently encountered with severe degrees of OSA. Increased sympathetic activation and impaired cardiac autonomic control as reflected by depressed baroreceptor reflex sensitivity (BRS) are possible mechanisms involved in the cardiovascular complications of OSA. However, it is not known at what stage of OSA that changes in BRS appear. The aim of this study was to evaluate BRS in patients with mild OSA.

METHODS

The study population consisted of 81 overweight patients with mild OSA and 46 body weight-matched non-OSA subjects. BRS, apnea-hypopnea index, body mass index, and metabolic parameters were assessed. The phenylephrine test was used to measure BRS.

RESULTS

Patients in the OSA group were slightly but significantly older than the non-OSA population (50.3±9.3 years vs 45.7±11.1 years, P=0.02). Body mass index, percentage body fat, blood pressure, fasting glucose, insulin, and lipid levels did not differ between the OSA patients and non-OSA subjects. Absolute BRS values in patients with mild OSA and non-OSA subjects (9.97±6.70 ms/mmHg vs 10.51±7.16 ms/mmHg, P=0.67) and BRS values proportional to age-related and sex-related reference values (91.4%±22.7% vs 92.2%±21.8%, P=0.84) did not differ from each other. BRS <50% of the sex-specific reference value was found in 6% of patients with mild OSA and in 2% of non-OSA subjects (P=0.29).

CONCLUSION

Patients with mild OSA did not show evidence of disturbed BRS in comparison with weight-matched non-OSA controls.

Sleep architecture following a weight loss intervention in overweight and obese patients with obstructive sleep apnea and type 2 diabetes: relationship to apnea-hypopnea index

STUDY OBJECTIVES

To determine if weight loss and/ or changes in apnea-hypopnea index (AHI) improve sleep architecture in overweight/ obese adults with type 2 diabetes (T2D) and obstructive sleep apnea (OSA).

METHODS

This was a randomized controlled trial including 264 overweight/ obese adults with T2D and OSA. Participants were randomized to an intensive lifestyle intervention (ILI) or a diabetes and support education (DSE) control group. Measures included anthropometry, AHI, and sleep at baseline and year-1, year-2, and year-4 follow-ups.

RESULTS

Changes in sleep duration (total sleep time [TST]), continuity [wake after sleep onset (WASO)], and architecture stage 1, stage 2, slow wave sleep, and REM sleep) from baseline to year 1, 2, and 4 did not differ between ILI and DSE. Repeated-measure mixed-model analyses including data from baseline through year-4 for all participants demonstrated a significant positive association between AHI and stage 1 sleep (p < 0.001), and a significant negative association between AHI and stage 2 (p = 0.01) and REM sleep (p < 0.001), whereas changes in body weight had no relation to any sleep stages or TST. WASO had a significant positive association with change in body weight (p = 0.009).

CONCLUSIONS

Compared to control, the ILI did not induce significant changes in sleep across the 4-year follow-up. In participants overall, reduced AHI in overweight/ obese adults with T2D and OSA was associated with decreased stage 1, and increased stage 2 and REM sleep. These sleep architecture changes are more strongly related to reductions in AHI than body weight, whereas WASO may be more influenced by weight than AHI.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00194259.

Effects of a pragmatic lifestyle intervention for reducing body mass in obese adults with obstructive sleep apnoea: a randomised controlled trial

This study investigated the effects of a pragmatic lifestyle intervention in obese adults with continuous positive airway pressure-treated obstructive sleep apnoea hypopnoea syndrome (OSAHS). Sixty patients were randomised 1 : 1 to either a 12-week lifestyle intervention or an advice-only control group. The intervention involved supervised exercise sessions, dietary advice, and the promotion of lifestyle behaviour change using cognitive-behavioural techniques. Outcomes were assessed at baseline (week 0), intervention end-point (week 13), and follow-up (week 26). The primary outcome was 13-week change in body mass. Secondary outcomes included anthropometry, blood-borne biomarkers, exercise capacity, and health-related quality of life. At end-point, the intervention group exhibited small reductions in body mass (−1.8 [−3.0, −0.5] kg; P = 0.007) and body fat percentage (−1 [−2, 0]%; P = 0.044) and moderate improvements in C-reactive protein (−1.3 [−2.4, −0.2] mg·L⁻¹; P = 0.028) and exercise capacity (95 [50, 139] m; P < 0.001). At follow-up, changes in body mass (−2.0 [−3.5, −0.5] kg; P = 0.010), body fat percentage (−1 [−2, 0]%; P = 0.033), and C-reactive protein (−1.3 [−2.5, −0.1] mg·L⁻¹; P = 0.037) were maintained and exercise capacity was further improved (132 [90, 175] m; P < 0.001). This trial is registered with ClinicalTrials.gov NCT01546792.

Long-term outcome of catheter ablation in atrial fibrillation patients with coexistent metabolic syndrome and obstructive sleep apnea: impact of repeat procedures versus lifestyle changes

INTRODUCTION

Metabolic syndrome (MS) and obstructive sleep apnea (OSA) are well-known independent risk factors for atrial fibrillation (AF) recurrence. This study evaluated ablation outcome in AF patients with coexistent MS and OSA and influence of lifestyle modifications (LSM) on arrhythmia recurrence.

METHODS AND RESULTS

We included 1,257 AF patients undergoing first catheter ablation (30% paroxysmal AF). Patients having MS + OSA were classified into Group 1 (n = 126; 64 ± 8 years; 76% male). Group 2 (n = 1,131; 62 ± 11 years; 72% male) included those with either MS (n = 431) or OSA (n = 112; no CPAP users) or neither of these comorbidities (n = 588). Patients experiencing recurrence after first procedure were divided into 2 subgroups; those having sporadic events (frequency < 2 months) remained on previously ineffective antiarrhythmic drugs (AAD) and aggressive LSM, while those with persistent arrhythmia (incessant or ≥2 months) underwent repeat ablation. After 34 ± 8 months of first procedure, 66 (52%) in Group 1 and 386 (34%) in Group 2 had recurrence (P < 0.001). Recurrence rate in only-MS, only-OSA, and without MS/OSA groups were 40%, 38%, and 29%, respectively. Patients with MS + OSA experienced substantially higher recurrence compared to those with lone MS or OSA (52% vs. 40% vs. 38%; P = 0.036). Of the 452 patients having recurrence, 250 underwent redo-ablation and 194 remained on AAD and LSM. At 20 ± 6 months, 76% of the redo group remained arrhythmia-free off AAD whereas 74% of the LSM group were free from recurrence (P = 0.71), 33% of which were off AAD.

CONCLUSIONS

MS and OSA have additive negative effect on arrhythmia recurrence following single procedure. Repeat ablation or compliant LSM increase freedom from recurrent AF.

Weight loss from lifestyle interventions and severity of sleep apnoea: a systematic review and meta-analysis

BACKGROUND

Excess body weight is a risk factor for obstructive sleep apnoea (OSA). The aim of the systematic review was to establish whether weight loss via lifestyle interventions such as diet and exercise are useful in the treatment of OSA.

METHODS

A literature search was conducted between 1980 and February 2012. Systematic reviews and randomised controlled trials (RCTs) with participants who had OSA, were overweight or obese, and who had undergone lifestyle interventions with the aim of improving sleep apnoea were included. Meta analyses were conducted for a subset of RCTs with appropriate data.

RESULTS

Two systematic reviews and eight RCTs were included. Meta-analyses were conducted for four RCTs comparing intensive lifestyle interventions to a control. The overall weighted mean differences for weight change, change in apnoea -hypopnoea index (AHI) and change in oxygen desaturation index of ≥4% were as follows: -13.76 kg (95% confidence interval (CI) -19.21, --8.32), -16.09 (95% CI -25.64, -6.54) and -14.18 (95% CI -24.23, -4.13), respectively. Although high heterogeneity within the meta analyses, all studies favoured the interventions. Long-term follow-up data from three RCTs suggest that improvements in weight and AHI are maintained for up to 60 months.

CONCLUSIONS

Intensive lifestyle interventions are effective in the treatment of OSA, resulting in significant weight loss and a reduction in sleep apnoea severity. Weight loss via intensive lifestyle interventions could be encouraged as a treatment for mild to moderate OSA.

Clinical Implications of Impaired Sleep

Despite its pervasiveness in primary care, deficient sleep often is underappreciated as a cue to other health risks. Accordingly, this review discusses contemporary evidence-based perspectives on impaired sleep and its associations with other lifestyle medicine concerns, including obesity, cardiovascular conditions, psychological problems, and health-compromising habits. The potential clinical benefits of promoting sleep health also will be considered.

The impact of pharyngeal fat tissue on the pathogenesis of obstructive sleep apnea

PURPOSE

Obesity is the most important risk factor for obstructive sleep apnea (OSA); however, the exact underlying mechanisms are still not fully understood. The aim of this study was to examine the morphology of upper airways in overweight habitual snorers and in mild OSA patients. Furthermore, the associations between weight loss, parapharyngeal fat pad area and OSA were assessed in a 1-year randomised, controlled follow-up study originally conducted to determine the effects of lifestyle changes with weight reduction as a treatment of OSA.

METHODS

Thirty-six overweight adult patients with mild OSA [apnea-hypopnea index (AHI) 5-15 events/h] and 24 weight-matched habitual snorers (AHI < 5 events/h) were included in the study. All patients underwent nocturnal cardiorespiratory recordings and multislice computed tomography (CT) of parapharyngeal fat pad area, the smallest diameter and area in naso-, oro- and hypopharynx, the smallest diameter and area of the whole pharyngeal airway, the distance from the hyoid bone to the mandibular plane and to cervical tangent as well as the distance between mandibular symphysis and cervical spine. In addition, OSA patients were further randomised to receive either an active 1-year lifestyle intervention with an early weight loss programme or routine lifestyle counselling. After 1 year, the cardiorespiratory recordings and CT scans were repeated.

RESULTS

The pharyngeal fat pad area was significantly larger, and the distance from the hyoid bone to cervical spine was longer in patients with OSA than in habitual snorers (p = 0.002 and p = 0.018, respectively). The multiple regression analysis showed that besides a large pharyngeal fat pad area and a long distance from the cervical spine to hyoid bone, also a short distance from the mandibular symphysis to cervical tangent increased a risk to OSA. During the 1-year follow-up in OSA patients, the pharyngeal fat pad area and AHI decreased significantly in the intervention group (p = 0.003 and p < 0.001, respectively).

CONCLUSIONS

In the early stages of OSA, the pharyngeal fat pad seems to play an important role in the development of disease in overweight patients. Furthermore, weight reduction by lifestyle intervention-based programme reduces both central obesity and pharyngeal fat pads, resulting in an improvement of OSA.

Long-term effect of weight loss on obstructive sleep apnea severity in obese patients with type 2 diabetes

STUDY OBJECTIVES

To examine whether the initial benefit of weight loss on obstructive sleep apnea (OSA) severity at 1 year is maintained at 4 years.

DESIGN

Randomized controlled trial with follow-up at 1, 2, and 4 years.

SETTING

4 Look AHEAD clinical centers.

PARTICIPANTS

Two hundred sixty-four obese adults with type 2 diabetes and OSA.

INTERVENTIONS

Intensive lifestyle intervention with a behavioral weight loss program or diabetes support and education.

MEASUREMENTS

Change in apnea-hypopnea index on polysomnogram.

RESULTS

The intensive lifestyle intervention group's mean weight loss was 10.7 ± 0.7 (standard error), 7.4 ± 0.7, and 5.2 ± 0.7 kg at 1, 2, and 4 years respectively, compared to a less than 1-kg weight loss for the control group at each time (P < 0.001). Apnea-hypopnea index difference between groups was 9.7 ± 2.0, 8.0 ± 2.0, and 7.7 ± 2.3 events/h at 1, 2 and 4 years respectively (P < 0.001). Change in apnea-hypopnea index over time was related to the amount of weight loss (P < 0.0001) and intervention, independent of weight loss (P = 0.001). Remission of OSA at 4 years was 5 times more common with intensive lifestyle intervention (20.7%) than diabetes support and education (3.6%).

CONCLUSIONS

Among obese adults with type 2 diabetes and OSA, intensive lifestyle intervention produced greater reductions in weight and apnea-hypopnea index over a 4 year period than did diabetes support and education. Beneficial effects of intensive lifestyle intervention on apneahypopnea index at 1 year persisted at 4 years, despite an almost 50% weight regain. Effect of intensive lifestyle intervention on apnea-hypopnea index was largely, but not entirely, due to weight loss.

Obstructive sleep apnoea and type 2 diabetes mellitus: a bidirectional association

Obstructive sleep apnoea and type 2 diabetes are common medical disorders that have important clinical, epidemiological, and public health implications. Research done in the past two decades indicates that obstructive sleep apnoea, through the effects of intermittent hypoxaemia and sleep fragmentation, could contribute independently to the development of insulin resistance, glucose intolerance, and type 2 diabetes. Conversely, type 2 diabetes might increase predisposition to, or accelerate progression of, obstructive and central sleep apnoea, possibly through the development of peripheral neuropathy and abnormalities of ventilatory and upper airway neural control. Although more research is needed to clarify the mechanisms underlying the bidirectional association between the two disorders, their frequent coexistence should prompt all health-care professionals to embrace clinical practices that include screening of a patient presenting with one disorder for the other. Early identification of obstructive sleep apnoea in patients with metabolic dysfunction, including type 2 diabetes, and assessment for metabolic abnormalities in those with obstructive sleep apnoea could reduce cardiovascular disease risk and improve the quality of life of patients with these chronic diseases.