Johanna Sahlman

Lifestyle intervention with weight reduction: first-line treatment in mild obstructive sleep apnea

RATIONALE Obesity is the most important risk factor for obstructive sleep apnea (OSA). However, although included in clinical guidelines, no randomized controlled studies have been performed on the effects of weight reduction on mild OSA. OBJECTIVES The aim of this prospective, randomized controlled parallel-group 1-year follow-up study was to determine whether a very low calorie diet (VLCD) with supervised lifestyle counseling could be an effective treatment for adults with mild OSA. METHODS Seventy-two consecutive overweight patients (body mass index, 28-40) with mild OSA were recruited. The intervention group (n = 35) completed the VLCD program with supervised lifestyle modification, and the control group (n = 37) received routine lifestyle counseling. The apnea-hypopnea index (AHI) was the main objectively measured outcome variable. Change in symptoms and the 15D-Quality of Life tool were used as subjective measurements. MEASUREMENTS AND MAIN RESULTS The lifestyle intervention was found to effectively reduce body weight (-10.7 +/- 6.5 kg; body mass index, -3.5 +/- 2.1 [mean +/- SD]). There was a statistically significant difference in the mean change in AHI between the study groups (P = 0.017). The adjusted odds ratio for having mild OSA was markedly lowered (odds ratio, 0.24 [95% confidence interval, 0.08-0.72]; P = 0.011) in the intervention group. All common symptoms related to OSA, and some features of 15D-Quality of Life improved after the lifestyle intervention. Changes in AHI were strongly associated with changes in weight and waist circumference. CONCLUSIONS VLCD combined with active lifestyle counseling resulting in marked weight reduction is a feasible and effective treatment for the majority of patients with mild OSA, and the achieved beneficial outcomes are maintained at 1-year follow-up.

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

BACKGROUND Obesity is the most important risk factor for obstructive sleep apnea (OSA). Weight-reduction programs have been observed to represent effective treatment of overweight patients with OSA. However, it is not known whether beneficial changes remain after the end of the intervention. OBJECTIVE The aim of the study was to assess the long-term efficacy of a lifestyle intervention based on a healthy diet and physical activity in a randomized, controlled, 2-y postintervention follow-up in OSA patients. DESIGN Eighty-one consecutive overweight [body mass index (in kg/m(2)): 28-40] adult patients with mild OSA were recruited. The intervention group completed a 1-y lifestyle modification regimen that included an early 12-wk weight-reduction program with a very-low-calorie diet. The control group received routine lifestyle counseling. During the second year, no dietary counseling was offered. Change in the apnea-hypopnea index (AHI) was the main objective outcome variable, and changes in symptoms were used as a subjective measurement. RESULTS A total of 71 patients completed the 2-y follow-up. The mean (± SD) changes in diet and lifestyle with simultaneous weight reduction (-7.3 ± 6.5 kg) in the intervention group reflected sustained improvements in findings and symptoms of OSA. After 2 y, the reduction in the AHI was significantly greater in the intervention group (P = 0.049). The intervention lowered the risk of OSA at follow-up; the adjusted odds ratio for OSA was 0.35 (95% CI: 0.12-0.97; P = 0.045). CONCLUSION Favorable changes achieved by a 1-y lifestyle intervention aimed at weight reduction with a healthy diet and physical activity were sustained in overweight patients with mild OSA after the termination of supervised lifestyle counseling. This trial was registered at clinicaltrials.gov as NCT00486746.

The activation of the inflammatory cytokines in overweight patients with mild obstructive sleep apnoea

It is widely accepted that obstructive sleep apnoea (OSA) is linked with cardiovascular diseases. The relationship is complex and remains still poorly understood. The presence of chronic systemic inflammation has been connected with pathogenesis of both OSA and cardiovascular diseases. While atherogenesis is believed to be a process of many years, little is known about the potential impact of the largest OSA subgroup, mild OSA, on the development of cardiovascular diseases. The aim of the present study was to assess whether untreated mild OSA is associated with an activation of inflammatory cytokine system. The adult study population consisted of two groups: 84 patients with mild OSA [apnoea–hypopnoea index (AHI) 5–15 h−1] and 40 controls (AHI <5 h−1). Serum concentrations of pro‐ and anti‐inflammatory cytokines were measured before any interventions. After adjustments for age, sex, body mass index, fat percentage, most important cardiometabolic and inflammatory diseases, and non‐steroidal anti‐inflammatory medication, the mean level of tumour necrosis factor‐α was significantly elevated (1.54 versus 1.17 pg mL−1, P = 0.004), whereas the level of interleukin‐1β (IL‐1β) was reduced (0.19 versus 0.23 pg mL−1, P = 0.004) in patients with mild OSA compared with controls. The concentrations of the protective anti‐inflammatory cytokines, interleukin‐10 (1.28 versus 0.70 pg mL−1, P < 0.001) and interleukin‐1 receptor antagonist (478 versus 330 pg mL−1, P = 0.003) were elevated in the OSA group. The concentrations of C‐reactive protein increased, but IL‐1β decreased along with the increase of AHI. Mild OSA was found to be associated not only with the activation of the pro‐inflammatory, but also with the anti‐inflammatory systems.

Evolution of Mild Obstructive Sleep Apnea after Different Treatments

Study Objectives: To evaluate the prognosis of mild obstructive sleep apnea in relation to different treatment modalities.

Effect of weight reduction on rhinometric measurements in overweight patients with obstructive sleep apnea

Background Elevated nasal resistance and obesity predispose to obstructive sleep apnea (OSA). Weight loss has been shown to result in an alleviation of OSA, but its effect on nasal airflow has not been studied. Methods This study was a prospective, randomized, controlled study with two parallel groups. A total of 52 adult overweight patients (body mass index [BMI], 28–40 kg/m2) with mild obstructive sleep apnea (apnea–hypopnea index {AHI}, 5–15) were randomized into two study groups. The intervention group (n = 26) followed a very low calorie diet with a supervised lifestyle intervention while the control group (n = 26) received routine lifestyle counseling. The changes in BMI, total nasal resistance, total nasal volume, and quality of life scores (Mini Rhinoconjunctivitis Quality of Life Questionnaire, MiniRQLQ) were assessed at baseline and after the intervention at 3 months. Results The reduction in BMI in the intervention group was significantly greater than that achieved by patients in the control group (5.4 kg/m2 versus 0.5 kg/m2). Accordingly, AHI was reduced by 3.2 events/hour in the intervention group and by 1.3 in the control group. However, there were no significant changes in rhinometric measurements despite significant weight loss. There was no correlation between the reduction of BMI and the change in nasal resistance or MiniRQLQ scores. Conclusion Weight reduction does not seem to have any effect on nasal resistance or volume in overweight patients with mild OSA. Patients with OSA and impaired nasal breathing need specific medical or surgical treatment to restore nasal airflow.

The impact of weight reduction in the prevention of the progression of obstructive sleep apnea: an explanatory analysis of a 5-year observational follow-up trial

BACKGROUND Obstructive sleep apnea (OSA) is a chronic progressive disease, and it is well-documented that severe OSA is associated with an increased cardiovascular morbidity and mortality. Weight reduction has been shown to improve OSA; however, we need further evidence to determine if it may prevent the progression of OSA in the long term. The aim of our study was to assess the impact of weight change during a 5-year observational follow-up of an original 1-year randomized controlled trial. METHODS The participants were divided into the two groups according to the weight change at 5-year follow-up using the 5% weight loss as a cutoff point, which was later referred to as the successful (n = 20) or unsuccessful groups (n = 27). The change in apnea-hypopnea index (AHI) was the main objective outcome variable. RESULTS Fifty-seven patients participated in the 5-year follow-up. At 5 years from the baseline, the change in AHI between the groups was significant in the successful group (-3.5 [95% confidence interval {CI}, -6.1 to -0.9]) compared with the unsuccessful group (5.0 [95% CI, 2.0-8.5]) (P = .002). Successful weight reduction achieved an 80% reduction in the incidence of progression of OSA compared to the unsuccessful group (log-rank test, P = .016). CONCLUSIONS A moderate but sustained weight reduction can prevent the progression of the disease or even cure mild OSA in obese patients.

Effect of weight loss on inflammation in patients with mild obstructive sleep apnea

BACKGROUND AND AIMS Inflammation may be one mediating mechanism for cardiovascular diseases in obstructive sleep apnea (OSA). However, little is known about subclinical inflammation or the effect of lifestyle intervention on inflammation in early stages of OSA. The aim of this substudy of an existing randomized controlled trial, with post hoc analyses, was to determine the impact of lifestyle changes aimed at weight reduction on inflammatory biomarkers in overweight patients with mild OSA. METHODS AND RESULTS Patients were randomized to supervised intensive lifestyle intervention group (N=28) or to control group (N=31), which received routine lifestyle advices. Circulating concentrations of pro- and anti-inflammatory mediators were measured before and after the 1-year intervention. The concentrations of two pro-inflammatory mediators, high-sensitivity C-reactive protein (hsCRP) and interleukin (IL)-6, decreased significantly in both groups. Although the changes in inflammatory biomarkers favored the supervised lifestyle intervention, the only significant reduction observed between the groups was for the anti-inflammatory IL-1 receptor antagonist (IL-1RA). The change in hsCRP was associated with apnea-hypopnea index, and improving night-time oxygen saturation was related to tumor necrosis factor alpha. IL-1RA and IL-6 were associated with insulin metabolism. CONCLUSION Weight loss resulted in reductions in concentrations of some pro- and anti-inflammatory mediators in overweight patients with mild OSA, overall favoring the supervised lifestyle intervention. These findings suggest that more intensive treatment of obesity in OSA patients might be well-justified.

Novel parameters reflect changes in morphology of respiratory events during weight loss

Apnea-hypopnea-index (AHI), disregarding the respiratory event morphology, is currently used in estimation of severity of obstructive sleep apnea (OSA). The purpose of the current study was to evaluate the potential of novel parameters in estimation of changes in severity of OSA during weight loss. Polygraphic data of 67 patients, 37 in the control (no weight loss) and 30 in the weight loss (>5%) groups was evaluated at baseline and after two year follow-up. Changes in the values of novel parameters, incorporating detailed information of respiratory event characteristics, were evaluated and compared with changes in AHI. The median AHI in the weight loss group decreased significantly during the follow-up. The number of shorter respiratory events decreased in the weight loss group, while the longer ones remained, increasing the median durations of the respiratory events by 20-62%. For this reason the decrease of the values of the novel parameters were smaller compared to AHI in the weight loss group. This suggests that the severity of OSA might not fall as linearly during weight loss as AHI suggests. Moreover, the novel parameters containing more detailed information on the morphology characteristics may provide valuable supplementary information for the assessment of the severity of OSA.

The association between anxiety and the degree of illness in mild obstructive sleep apnoea

Obstructive sleep apnoea (OSA) has been reported to associate with anxiety, but earlier observations are scarce and the role of the persistence of anxiety in this connection is unclear.

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.