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Objective: Sleep-disordered breathing (SDB) is prevalent in obesity. Weight loss is one of the most effective treatment options. The aim was to assess the association of SDB and metabolic disruption before and after weight loss., Design and Methods: Obese adolescents were included when entering an in-patient weight loss program. Fasting blood analysis was performed at baseline and after 4-6 months. Sleep screening was done at baseline and at follow-up in case of baseline SDB., Results: 224 obese adolescents were included. Median age was 15.5 years (10.1-18.0) and mean BMI z-score was 2.74 ± 0.42. About 30% had SDB at baseline (N = 68). High-density lipoprotein (HDL)-cholesterol was associated with mean nocturnal oxygen saturation () (partial r = 0.21; P = 0.002). Aspartate aminotransferase (ASAT) and alanine aminotransferase were related with oxygen desaturation index (partial r = -0.15; P = 0.03 and partial r = -0.15; P = 0.02), but this became insignificant after correction for sex. After weight loss, 24% had residual SDB. Linear regression showed an association between ASAT and (partial r = -0.34; P = 0.002). There were no significant correlations between improvements in laboratory measurements and sleep parameters. HDL-cholesterol improved in relation with the decrease in BMI z-score., Conclusion: SDB at baseline was associated with higher levels of liver enzymes and lower HDL-cholesterol concentration. Improvements in sleep parameters were not associated with improvements in laboratory measurements., (Copyright © 2013 The Obesity Society.)

Sleep-disordered breathing (SDB) is prevalent in childhood obesity. It may be an independent risk factor for the metabolic syndrome. Possible mechanisms are inflammation and oxidative stress. Adenotonsillectomy in childhood obesity is associated with a high recurrence rate and risk of postoperative weight gain. Therefore, this study assessed the effects of SDB on inflammation and oxidative stress in childhood obesity before and after weight loss. We included 132 obese subjects between 10 and 18 years consecutively. Median age was 15.4 years (10.1-18.0). Mean BMI z-score was 2.72 ± 0.42. Leukocytes and differentiation, high sensitivity C-reactive protein (hs-CRP), and uric acid (UA) were determined at baseline and subjects underwent a sleep assessment. SDB was diagnosed in 39%. Linear regression analysis showed an association between UA(log) and oxygen desaturation index(log) (ODI(log)) (r = 0.20; P = 0.03), between leukocytes(log) and respiratory disturbance index(log) (RDI(log)) (r = 0.23; P = 0.01), and between lymphocytes(log) and RDI(log) (r = 0.19; P = 0.04). Follow-up was organized after 4-6 months of treatment. Median decrease in BMI z-score was 32%. Laboratory measurements were repeated. Subjects with SDB at baseline underwent a second sleep study. Of these 49 subjects, 12 showed residual SDB. This corresponds with a treatment success rate of 71%. Unlike changes in inflammatory markers, improvements in UA were associated with improvements in RDI and ODI (respectively: r = 0.44; P = 0.007, r = 0.41; P = 0.01). In conclusion, weight loss is effective in treating obese children with SDB. At baseline, a link exists between inflammation and SDB. Oxidative stress is reflected by UA at baseline and the concentration decreases after treatment according to improvements in SDB.

Background: To investigate the relationship between obstructive sleep apnea syndrome (OSAS) and exhaled nitric oxide (eNO) in overweight children and adolescents without asthma or atopy and to assess whether obesity per se is associated with increased airway inflammation., Methods: Consecutive overweight subjects without symptoms of asthma or allergy were recruited at a pediatric obesity clinic. A normal-weight control group without OSAS and asthma or allergy was also recruited. All subjects underwent polysomnography and two measurements of eNO (afternoon and morning after polysomnography)., Results: Controlling for age, the mean (+/- SD) afternoon eNO concentration was significantly higher in the snoring group (14.1 +/- 1.1 parts per billion [ppb]) compared with the normal-weight group (10.1 +/- 0.8 ppb; p = 0.03) and with the overweight group with normal polysomnography findings (8.9 +/- 0.8 ppb; p = 0.007). The afternoon eNO concentration was also different between the OSAS group (11.9 +/- 1.0 ppb) and the overweight group with normal polysomnography findings (p = 0.03). Morning eNO values were higher in the OSAS group (12.3 +/- 1.1 ppb) than in the normal weight group (9.9 +/- 0.8 ppb; p = 0.047) and in the overweight control group (9.7 +/- 0.7 ppb; p = 0.02). BMI z score was not significantly correlated with afternoon eNO concentration or with morning eNO concentration., Conclusion: This study illustrates that both habitual snoring and OSAS are associated with increased airway inflammation in overweight children as assessed by higher eNO levels. Furthermore, it was demonstrated that childhood obesity in the absence of sleep-disordered breathing is not associated with increased airway inflammation.

Objective: To assess if the severity of sleep-disordered breathing (SDB) and mainly intermittent hypoxia is associated with increased peripheral leukocytes in overweight children and adolescents, controlling for adiposity and obesity-related metabolic abnormalities., Methods: Consecutive subjects were recruited at a pediatric obesity clinic. All subjects underwent polysomnography and a fasting blood sample., Results: In total, 95 subjects were included ( =11.1+/-2.6, 43 boys, body mass index, =2.3+/-0.5, 29 subjects were overweight and 66 obese). Total white blood cell count increased significantly by worsening of intermittent hypoxia. Total white blood cell count was correlated with the maximal degree of desaturation, independent of puberty, HOMA and HDL-cholesterol. Neutrophil levels were associated with the degree of desaturation, while controlling for puberty and HOMA., Conclusion: This study supports the hypothesis of an independent interaction between intermittent hypoxia and nocturnal desaturation during sleep, and increased white blood cell and neutrophil levels in overweight and obese children and adolescents. This finding may contribute to the mechanisms linking SDB with increased cardiovascular morbidity.

Objective: The aim of this study was to determine whether the severity of sleep-disordered breathing (SDB) was associated with increased levels of uric acid (UA), both in serum and in urine, as a marker of tissue hypoxia, in a sample of overweight and obese subjects, irrespective of indexes of adiposity., Methods: Consecutive subjects underwent polysomnography, fasting blood sampling, and 24-h urine collection. Outcome parameters were serum UA, UA excretion ([24-h urinary UA x serum creatinine]/urine creatinine) and urinary UA/creatinine ratio., Results: A total of 93 subjects were included (44% boys; mean [+/- SD] age = 11.1 +/- 2.5; 73% obese). A fasting measurement of serum UA levels was available for 62 patients. The respiratory disturbance index was a significant covariate (beta = 0.09 +/- 0.03; p = 0.01) in the regression model for serum UA, controlling for sex (beta = 0.32 +/- 0.29; p = 0.3), puberty (beta = 0.87 +/- 0.34; p = 0.01), and waist circumference (beta = 0.04 +/- 0.01; p = 0.005). The percentage of total sleep time with arterial oxygen saturation < or = 89% (beta = 0.94 +/- 0.45; p = 0.04) was also significantly associated with serum UA level, controlling for sex (beta = 0.22 +/- 0.30; p = 0.5), puberty (beta = 0.83 +/- 0.35; p = 0.02), and waist circumference (beta = 0.04 +/- 0.02; p = 0.02). None of the SDB variables correlated with UA excretion or with urinary UA/creatinine ratio., Conclusion: This study in overweight children and adolescents demonstrated a relationship between the severity of sleep apnea and increased levels of serum UA, independent of abdominal adiposity. In view of the known associations between UA and cardiovascular risk, this finding may contribute to the mechanisms linking SDB with cardiovascular morbidity.

Aims: To determine the prevalence of sleep-disordered breathing (SDB) in a clinical sample of overweight and obese children and adolescents, and to examine the contribution of fat distribution., Methods: Consecutive subjects without chronic lung disease, neuromuscular disease, laryngomalacia, or any genetic or craniofacial syndrome were recruited. All underwent measurements of neck and waist circumference, waist-to-hip ratio, % fat mass and polysomnography. Obstructive apnoea index > or =1 or obstructive apnoea-hypopnoea index (OAHI) > or =2, further classified as mild (2< or =OAHI<5) or moderate-to-severe (OAHI> or =5), were used as diagnostic criteria for obstructive sleep apnoea (OSA). Central sleep apnoea was diagnosed when central apnoeas/hypopnoeas > or =10 s were present accompanied by >1 age-specific bradytachycardia and/or >1 desaturation <89%. Subjects with desaturation < or =85% after central events of any duration were also diagnosed with central sleep apnoea. Primary snoring was diagnosed when: snoring was detected by microphone and normal obstructive indices and saturation., Results: 27 overweight and 64 obese subjects were included (40 boys; mean (standard deviation (SD)) age 11.2 (2.6) years). Among the obese children, 53% were normal, 11% had primary snoring, 11% had mild OSA, 8% had moderate-to-severe OSA and 17% had central sleep apnoea. Half of the patients with central sleep apnoea had desaturation <85%. Only enlarged tonsils were predictive of moderate-to-severe OSA. On the other hand, higher levels of abdominal obesity and fat mass were associated with central sleep apnoea., Conclusion: SDB is very common in this clinical sample of overweight children. OSA is not associated with abdominal obesity. On the contrary, higher levels of abdominal obesity and fat mass are associated with central sleep apnoea.