Sleep-disordered breathing in obese adolescents is associated with visceral adiposity and markers of insulin resistance

Pediatric Obesity: Complications and Current Day Management

Obesity affects approximately 1 in 5 youth globally and increases the risk of complications during adolescence and young adulthood, including type 2 diabetes, dyslipidemia, hypertension, non-alcoholic fatty liver disease, obstructive sleep apnea, and polycystic ovary syndrome. Children and adolescents with obesity frequently experience weight stigma and have an impaired quality of life, which may exacerbate weight gain. Pediatric obesity is typically defined using sex-, age-, and population-specific body mass index percentiles. Once identified, pediatric obesity should always be managed with lifestyle modification. However, adolescents with obesity may also benefit from anti-obesity medications (AOM), several of which have been approved for use in adolescents by the US Food and Drug Administration, including liraglutide, phentermine/topiramate, and semaglutide. For children with specific, rare monogenic obesity disorders, setmelanotide is available and may lead to significant weight loss. Metabolic and bariatric surgery may be used for the management of severe obesity in youth; though highly effective, it is limited to specialized centers and has had relatively low pediatric uptake. In this narrative review using pediatric-focused data from original research, reviews, clinical practice guidelines, governmental agencies, and pharmaceutical companies, we review obesity-related metabolic complications in youth and management strategies, including AOM and bariatric surgery.

Visceral adiposity is related to insulin sensitivity and inflammation in adolescents with obesity and mild sleep disordered breathing

OBJECTIVES

To evaluate the relationships between adipose tissue distribution, insulin secretion and sensitivity, sleep-disordered breathing, and inflammation in obese adolescents.

METHODS

Cross-sectional study of 56 obese adolescents who underwent anthropometric measures, dual-energy X-ray absorptiometry, overnight polysomnography, oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test. Correlation and regression analyses were used to assess relationships between adiposity, insulin secretion and sensitivity, measures of sleep-disordered breathing (oxyhemoglobin nadir, SpO₂; apnea hypopnea index, AHI; arousal index, AI; maximum end-tidal CO₂; non-REM sleep duration), and inflammation (high-sensitivity C-reactive protein, hsCRP).

RESULTS

Subjects (55% female) were mean (SD) 14.4 (2.1) years, with BMI Z-score of 2.3 (0.4). AHI was >5 in 10 (18%) subjects and 1< AHI ≤5 in 22 (39%). Visceral adipose tissue area (VAT) was positively correlated with OGTT 1 and 2 h insulin and 1 h glucose, and hsCRP (r=0.3-0.5, p≤0.007 for each). VAT was negatively correlated with sensitivity to insulin (r=-0.4, p=0.005) and SpO₂ nadir (r=-0.3, p=0.04) but not with other sleep measures. After adjustment for BMI-Z, sex, population ancestry, age, and sleep measures, VAT remained independently associated with insulin measures and 1 h glucose, but no other measures of glycemia. SAT was not associated with measures of glycemia or insulin resistance.

CONCLUSIONS

Among adolescents with obesity, visceral adiposity was associated with insulin resistance, SpO₂ nadir, and inflammation. The independent association of visceral adiposity with insulin resistance highlights the potential role of VAT in obesity-related chronic disease.

Association of Pediatric Obstructive Sleep Apnea With Elevated Blood Pressure and Orthostatic Hypertension in Adolescence

Importance

Although pediatric guidelines have delineated updated thresholds for elevated blood pressure (eBP) in youth and adult guidelines have recognized obstructive sleep apnea (OSA) as an established risk factor for eBP, the relative association of pediatric OSA with adolescent eBP remains unexplored.

Objective

To assess the association of pediatric OSA with eBP and its orthostatic reactivity in adolescence.

Design, Setting, and Participants

At baseline of this population-based cohort study (Penn State Child Cohort) in 2000-2005, a random sample of 700 children aged 5 to 12 years from the general population was studied. A total of 421 participants (60.1%) were followed up in 2010-2013 after 7.4 years as adolescents (ages, 12-23 years). Data analyses were conducted from July 6 to October 29, 2020.

Main Outcomes and Measures

Outcomes were the apnea-hypopnea index (AHI) score, ascertained via polysomnography conducted in a laboratory; eBP measured in the seated position identified using guideline-recommended pediatric criteria; orthostatic hyperreactivity identified with BP assessed in the supine and standing positions; and visceral adipose tissue assessed via dual-energy x-ray absorptiometry.

Results

Among the 421 participants (mean [SD] age at follow-up, 16.5 [2.3] years), 227 (53.9%) were male and 92 (21.9%) were racial/ethnic minorities. A persistent AHI of 2 or more since childhood was longitudinally associated with adolescent eBP (odds ratio [OR], 2.9; 95% CI 1.1-7.5), while a remitted AHI of 2 or more was not (OR, 0.9; 95% CI 0.3-2.6). Adolescent OSA was associated with eBP in a dose-response manner; however, the association of an AHI of 2 to less than 5 among adolescents was nonsignificant (OR, 1.5; 95% CI, 0.9-2.6) and that of an AHI of 5 or more was approximately 2-fold (OR, 2.3; 95% CI, 1.1-4.9) after adjusting for visceral adipose tissue. An AHI of 5 or more (OR, 3.1; 95% CI, 1.2-8.5), but not between 2 and less than 5 (OR, 1.3; 95% CI, 0.6-3.0), was associated with orthostatic hyperreactivity among adolescents even after adjusting for visceral adipose tissue. Childhood OSA was not associated with adolescent eBP in female participants, while the risk of OSA and eBP was greater in male participants.

Conclusions and Relevance

The results of this cohort study suggest that childhood OSA is associated with adolescent hypertension only if it persists during this developmental period. Visceral adiposity explains a large extent of, but not all, the risk of hypertension associated with adolescent OSA, which is greater in male individuals.

Sleep-disordered breathing in adolescents with obesity: When does it start to affect cardiometabolic health?

BACKGROUND AND AIMS

Pediatric obesity and sleep-disordered breathing (SDB) are associated with cardiometabolic risk (CMR), but the degree of severity at which SDB affects cardiometabolic health is unknown. We assessed the relationship between the CMR and the apnea-hypopnea index (AHI), to identify a threshold of AHI from which an increase in the CMR is observed, in adolescents with obesity. We also compared the clinical, cardiometabolic and sleep characteristics between adolescents presenting a high (CMR+) and low CMR (CMR-), according to the threshold of AHI.

METHODS AND RESULTS

114 adolescents with obesity were recruited from three institutions specialized in obesity management. Sleep and SDB as assessed by polysomnography, anthropometric parameters, fat mass (FM), glucose and lipid profiles, and blood pressure (BP) were measured at admission. Continuous (MetScore_FM) and dichotomous (metabolic syndrome, MetS) CMR were determined. Associations between MetScore_FM and AHI adjusted for BMI, sex and age were assessed by multivariable analyses. Data of 82 adolescents were analyzed. Multivariable analyses enabled us to identify a threshold of AHI = 2 above which we observed a strong and significant association between CMR and AHI (Cohen's d effect-size = 0.57 [0.11; 1.02] p = 0.02). Adolescents with CMR+ exhibited higher MetScore_FM (p < 0.05), insulin resistance (p < 0.05), systolic BP (p < 0.001), sleep fragmentation (p < 0.01) and intermittent hypoxia than CMR- group (p < 0.0001). MetS was found in 90.9% of adolescents with CMR+, versus 69.4% in the CMR- group (p < 0.05).

CONCLUSIONS

The identification of a threshold of AHI ≥ 2 corresponding to the cardiometabolic alterations highlights the need for the early management of SDB and obesity in adolescents, to prevent cardiometabolic diseases.

CLINICAL TRIALS

NCT03466359, NCT02588469 and NCT01358773.

Association of sleep disturbances with obesity, insulin resistance and the metabolic syndrome

Insufficient sleep, which has become endemic in recent years, has been variably associated with increased risk of obesity, disorders of glucose and insulin homeostasis, and the metabolic syndrome; to a lesser degree, so has excessive sleep. This review summarizes recent epidemiological and pathophysiological evidence linking sleep disturbances (primarily abnormalities of sleep duration) with obesity, insulin resistance, type 2 diabetes and the metabolic syndrome in children and adults.

Comparison of β-Cell Function Between Overweight/Obese Adults and Adolescents Across the Spectrum of Glycemia

OBJECTIVE

Type 2 diabetes is a growing health problem among both adults and adolescents. To better understand the differences in the pathogenesis of diabetes between these groups, we examined differences in β-cell function along the spectrum of glucose tolerance.

RESEARCH DESIGN AND METHODS

We evaluated 89 adults and 50 adolescents with normal glucose tolerance (NGT), dysglycemia, or type 2 diabetes. Oral glucose tolerance test results were used for C-peptide and insulin/glucose minimal modeling. Model-derived and direct measures of insulin secretion and insulin sensitivity were compared across glycemic stages and between age-groups at each stage.

RESULTS

In adolescents with dysglycemia, there was marked insulin resistance (insulin sensitivity index: adolescents, median [interquartile range] 1.8 [1.1-2.4] × 10^-4; adults, 5.0 [2.3-9.9]; P = 0.01). The nature of β-cell dysfunction across stages of dysglycemia differed between the groups. We observed higher levels of secretion among adolescents than adults (total insulin secretion: NGT, 143 [103-284] × 10^-9/min adolescent vs. 106 [71-127], P = 0.001); adults showed stepwise impairments in static insulin secretion (NGT, 7.5 [4.0-10.3] × 10^-9/min; dysglycemia, 5.0 [2.3-9.9]; type 2 diabetes, 0.7 [0.1-2.45]; P = 0.003), whereas adolescents showed diabetes-related impairment in dynamic secretion (NGT, 1,905 [1,630-3,913] × 10^-9; dysglycemia, 2,703 [1,323-3,637]; type 2 diabetes, 1,189 [269-1,410]; P = 0.001).

CONCLUSIONS

Adults and adolescents differ in the underlying defects leading to dysglycemia, and in the nature of β-cell dysfunction across stages of dysglycemia. These results may suggest different approaches to diabetes prevention in youths versus adults.

Characteristics of Obstructive Sleep Apnea Across the Spectrum of Glucose Tolerance in Obese Adolescents

BACKGROUND

It is not known if dysglycemia and sleep-disordered breathing are linked in adolescents, as in adults.

OBJECTIVE

To perform a pilot study evaluating measures of sleep-disordered breathing across the spectrum of glucose tolerance in obese adolescents. We hypothesized that dysglycemia would be associated with sleep-disordered breathing.

PARTICIPANTS/METHODS

This was a prospective, cross-sectional clinical pilot study that included 57 adolescents [body mass index (BMI) 38.9 ± 8.4 kg/m²] aged 12-18 years (14.5 ± 1.6) with normal glucose tolerance (NGT), or dysglycemia [impaired glucose tolerance (IGT) or type 2 diabetes (T2D)].

MEASURES

Anthropometrics, overnight polysomnogram, and oral glucose tolerance tests were performed. Participant characteristics and outcome measures were compared by glucose tolerance status. Correlational analyses were conducted to assess the associations between variables of interest.

RESULTS

Participants with dysglycemia (n = 21) were not different from those with NGT (n = 36) for BMI, waist circumference, body fat, or sleep characteristics. Nocturnal oxygen desaturation was associated with higher BMI (r = -0.334, p = 0.012). The apnea-hypopnea index (AHI) was not associated with physical and metabolic parameters. Although participants with dysglycemia tended to have higher AHIs (median 3.2, 2.2, and 1.6 events/h for T2D, IGT, and NGT, respectively), there was not a linear relationship between measures of glycemia and AHI.

CONCLUSION

Further study with a larger proportion of youth with prediabetes and T2D is necessary to determine whether evaluation for sleep-disordered breathing is uniformly warranted.

Poor Sleep and Obesity: Concurrent Epidemics in Adolescent Youth

Poor sleep and obesity are both extraordinarily common in the US adolescent population and often occur simultaneously. This review explores the links between obesity and sleep, outlining what is known about the relationships between sleep characteristics, obesity, and cardiometabolic risk factors in youth. Sleep duration is less than optimal in teens, and decreases as age increases. This is detrimental to overall well-being and is associated with obesity in children, adolescents, and young adults. Accordingly, inadequate sleep duration is associated with poor diet quality, decreased insulin sensitivity, hyperglycemia, and prevalent cardiometabolic risk factors. Evidence suggests that poor sleep quality and altered circadian timing characterized by a preferred later sleep onset, known as "adolescent chronotype," contributes to shortened sleep duration. Obstructive sleep apnea (OSA) occurs more frequently among youth with obesity, and is associated with autonomic nervous system activity promoting higher blood pressure, increased markers of cardiovascular disease risk, and insulin resistance. While there is a clear association between OSA and type 2 diabetes in adults, whether or not this association is prevalent in youth is unclear at this time. Interventions to improve both sleep duration and quality, and obesity in adolescents are scarce and more evidence is needed to determine if such interventions can improve obesity-related health outcomes.

Increased inflammation from childhood to adolescence predicts sleep apnea in boys: A preliminary study

While chronic systemic inflammation in obstructive sleep apnea (OSA) has been traditionally considered a consequence of intermittent hypoxia, several treatment studies targeting inflammation suggest that this process may precede the development of the disorder. A recent cross-sectional study in the Penn State Child Cohort (PSCC) revealed that inflammation largely mediates the association between visceral adiposity and OSA in adolescence. The purpose of this study was to examine for the first time whether, longitudinally, inflammation precedes OSA during this developmental period. A subsample of the PSCC with longitudinal sleep and inflammation data (n=51) was included in this study. Participants underwent 9-h polysomnography (22:00-7:00), physical exam, and fasting morning blood draw at both time points. Plasma C-reactive protein (CRP) was measured via ELISA. At follow-up, visceral, subcutaneous, and total fat area were assessed via dual X-ray absorptiometry. Sex differences in body composition emerged in adolescence, with boys having more visceral adiposity than girls. Longitudinal increases in waist circumference from childhood to adolescence were associated with increases in CRP (ΔCRP) and follow-up CRP in boys, but not girls. Furthermore, in boys, ΔCRP was associated with higher follow-up apnea/hypopnea index (AHI). When ΔCRP was entered into a model predicting follow-up AHI, Δwaist circumference was no longer significant, indicating that inflammation largely explains the association between increasing central obesity and OSA severity. These preliminary findings, in a longitudinal, non-clinical sample of children developing OSA, suggest that inflammation derived from visceral adipose tissue precedes the development of the disorder, suggesting a potential causal mechanism.

Metabolic Consequences of Obstructive Sleep Apnea in Adolescents with Obesity: A Systematic Literature Review and Meta-Analysis

BACKGROUND

Adolescents who are obese are at high risk of developing obstructive sleep apnea (OSA). Although there is clear evidence associating OSA with metabolic dysfunction in adults, the evidence is less clear cut with adolescents. The purpose of this review was determine the association of sleep apnea with dyslipidemia, insulin resistance, cardiovascular disease risk, nonalcoholic fatty liver disease, and difficulty with weight loss in adolescents.

METHODS

A systematic literature review using PubMed, Scopus, CINAHL, Google Scholar, and PsycINFO was performed and articles were screened and reviewed with an a priori protocol.

RESULTS

Sixteen articles were included in qualitative synthesis and 10 were included in meta-analysis. Results from the meta-analysis indicate that OSA in adolescents is associated with greater risk of dyslipidemia, insulin resistance, and hypertension.

CONCLUSIONS

Although obesity leads to increased metabolic risk, OSA appears to independently increase metabolic impairment. Adolescents with obesity should be frequently screened for OSA to determine need for treatment and reduce this metabolic burden.

Inflammation mediates the association between visceral adiposity and obstructive sleep apnea in adolescents

Only a handful of studies, primarily in clinical samples, have reported an association between obesity, inflammation, and obstructive sleep apnea (OSA) in children and adolescents. No studies, however, have examined the pathogenetic link between visceral adiposity, systemic inflammation, and incident OSA in a large general population sample using objective measures of sleep and body fat. Adolescents (n = 392; mean age 17.0 ± 2.2 yr, 54.0% male) from the Penn State Child Cohort (PSCC) underwent 9-h overnight polysomnography; a DXA scan to assess body fat distribution; and a single fasting blood draw for the assessment of plasma interleukin-6 (IL-6), IL-6 soluble receptor (IL-6 sR), tumor necrosis factor alpha (TNFα), tumor necrosis factor receptor 1A (TNFR1), C-reactive protein (CRP), leptin, and adiponectin levels via ELISA. Visceral fat area was significantly elevated in moderate OSA (AHI ≥ 5), especially in boys. IL-6, CRP, and leptin were highest in adolescents with moderate OSA, even after adjusting for BMI percentile. Mediation analysis revealed that 42% of the association between visceral fat and OSA in adolescents was mediated by IL-6 (p = 0.03), while 82% of the association was mediated by CRP (p = 0.01). These data are consistent with the model of a feed-forward, vicious cycle, in which the release of proinflammatory cytokines by visceral adipocytes largely explains the association between central obesity and OSA; in turn, inflammation is also elevated in OSA independent of BMI. These findings, in a large, representative, non-clinical sample of young people, add to our understanding of the developmental pathogenesis of sleep apnea.

High-intensity interval training programme for obese youth (HIP4YOUTH): A pilot feasibility study

Recently, there has been growing interest in high-intensity interval training (HIT) as a strategy to improve health. In this pilot study, we examined the feasibility of a 4-week low-volume HIT and its effects on cardiorespiratory fitness (CRF), blood pressure (BP) and enjoyment in overweight and obese youth. Twelve adolescents (body mass index (BMI): 34.8 ± 3.9 kg · m^‒2, 14.9 ± 1.5 years) participated in 12 sessions of HIT (10 × 60 s cycling bouts eliciting ~90% maximal heart rate, interspersed with 90 s recovery, 30 min/session, 3 sessions/week) over ~4 weeks. All the participants completed the study and exercise attendance averaged 92%. Despite no changes in body weight and total fat, HIT resulted in significant (P < 0.01) increases in CRF (pre: 20.1 versus post: 22.2 ml · kg^‒1 · min^‒1) and exercise time (pre: 425 versus post: 509 s) during peak oxygen uptake test, and a reduction in resting systolic BP (pre: 115.8 versus post: 107.6 mmHg). The majority of study participants (83%) enjoyed HIT and more than half of the participants (58%) reported that HIT is a more enjoyable form of exercise compared to other types of exercises. Low-volume HIT is a useful strategy to promote exercise participation and improve cardiovascular health in overweight and obese youth.

Role of sleep quality in the metabolic syndrome

Emerging evidence has assigned an important role to sleep as a modulator of metabolic homeostasis. The impact of variations in sleep duration, sleep-disordered breathing, and chronotype to cardiometabolic function encompasses a wide array of perturbations spanning from obesity, insulin resistance, type 2 diabetes, the metabolic syndrome, and cardiovascular disease risk and mortality in both adults and children. Here, we critically and extensively review the published literature on such important issues and provide a comprehensive overview of the most salient pathophysiologic pathways underlying the links between sleep, sleep disorders, and cardiometabolic functioning.

Impact of Adenotonsillectomy on Insulin Resistance and Lipoprotein Profile in Nonobese and Obese Children

BACKGROUND

OSA associates with insulin resistance (IR), hyperglycemia, and dyslipidemia consistently in adults, but inconsistently in children. We set out to quantify the impact of OSA treatment upon obesity and metabolic outcomes and thus assess causality.

METHODS

Sixty-nine children with OSA; mean age, 5.9 years (range, 3-12.6); 55% boys; and 68% nonobese (NOB) underwent baseline overnight polysomnography, anthropometric and metabolic measurements, adenotonsillectomy (T&A), and follow-up testing a mean 7.9 months (range, 2-20) later.

RESULTS

Fifty-three children (77% of study cohort; 91% of obese children) had residual OSA (apnea-hypopnea index > 1 event/h) post-T&A. Fasting plasma insulin (FPI, 14.4 ± 9.4 → 12.6 ± 9.7 μIU/mL, P = .008), homeostasis model assessment-IR (3.05 ± 2.13 → 2.62 ± 2.22, P = .005), and high-density lipoprotein (HDL) (51.0 ± 12.9 → 56.5 ± 14.4 mg/dL, P = .007) improved despite increased BMI z score (1.43 ± 0.78 → 1.52 ± 0.62, P = .001); changes did not differ significantly between sexes or NOB and obese participants; however, post-T&A BMI z score rather than apnea-hypopnea index was the main predictor of levels of follow-up FPI, HDL, and other metabolic parameters. Higher baseline FPI and BMI-z predicted likelihood of residual OSA; conversely, on regression analysis, follow-up IR, HDL, and triglycerides were predicted by BMI z score, not residual OSA.

CONCLUSIONS

T&A improved IR and HDL, and residual OSA is predicted by baseline FPI and BMI z score, indicating a causal relationship; however, following T&A, residual metabolic dysfunction related to underlying adiposity rather than remaining sleep-disordered breathing. Finally, T&A cured OSA in < 25% of all children and only 10% of obese children; post-T&A polysomnography is indicated to assess which children still require treatment.

Natural history of sleep disordered breathing in prepubertal children transitioning to adolescence

Because there is a lack of agreed upon diagnostic criteria, it is critical to understand the natural history of obstructive sleep apnoea (OSA) in children in order to establish treatment strategies based on objective data.The Penn State Child Cohort is a representative, general-population sample of 700 elementary school children at baseline, of whom 421 were reassessed 8 years later, during adolescence.The remission of childhood apnoea-hypopnoea index (AHI) ≥2 events per h in adolescence was 52.9%. Using the higher threshold of AHI ≥5 events per h, remission was 100.0%, with 50.0% partially remitting to AHI 2- <5 events per h and the other half remitting to AHI <2 events per h. The incidence of adolescent AHI ≥2 events per h in those with childhood AHI <2 events per h was 36.5%, while the incidence of AHI ≥5 events per h in those with childhood AHI <5 events per h was 10.6%. This longitudinal study confirms that prepubertal OSA tends to resolve naturally during the transition to adolescence, and that primary snoring and mild sleep disordered breathing (SDB) do not appear to be strongly associated with progression to more severe SDB.The key risk factors for SDB in adolescence are similar to those found in middle-aged adults (i.e. male sex, older age and obesity). Moreover, consistent with recent studies in adults, this study includes the novel cross-sectional finding that visceral fat is associated with SDB as early as adolescence.

Impact of obstructive sleep apnoea on insulin resistance in nonobese and obese children

Obstructive sleep apnoea (OSA) has been inconsistently associated with insulin resistance and adverse metabolic states. We aimed to assess independent contributions of OSA to insulin resistance and dyslipidaemia in a large paediatric cohort.

Habitually snoring children underwent overnight polysomnography, anthropometric measurements and fasting laboratory evaluations. Primary outcome measures included insulin, glucose, homeostasis model of insulin resistance, lipoproteins and sleep disturbance measures.

Among 459 children aged 5–12 years, obesity was the primary driver of most associations between OSA and metabolic measures, but sleep duration was inversely associated with glucose levels, with N3 and rapid eye movement (REM) sleep being negatively associated and sleep fragmentation positively associated with insulin resistance measures. In children with mild OSA, the presence of obesity increased the odds for insulin resistance, while higher apnoea/hypopnoea index values emerged among obese children who were more insulin-resistant.

The exclusive presence of interactions between OSA and obesity in the degree of insulin resistance is coupled with synergistic contributions by sleep fragmentation to insulin resistance in the context of obesity. Insufficient N3 or REM sleep may also contribute to higher glycaemia independently of obesity. Studies are needed to better delineate the roles of puberty and sleep fragmentation in insulin resistance and the metabolic syndrome.

The changing face of diabetes in youth: lessons learned from studies of type 2 diabetes

The incidence of youth type 2 diabetes (T2D), linked with obesity and declining physical activity in high-risk populations, is increasing. Recent multicenter studies have led to a number of advances in our understanding of the epidemiology, pathophysiology, diagnosis, treatment, and complications of this disease. As in adult T2D, youth T2D is associated with insulin resistance, together with progressive deterioration in β cell function and relative insulin deficiency in the absence of diabetes-related immune markers. In contrast to adult T2D, the decline in β cell function in youth T2D is three- to fourfold faster, and therapeutic failure rates are significantly higher in youth than in adults. Whether the more aggressive nature of youth T2D is driven by genetic heterogeneity or physiology/metabolic maladaptation is yet unknown. Besides metformin, the lack of approved pharmacotherapeutic agents for youth T2D that target the pathophysiological mechanisms is a major barrier to optimal diabetes management. There is a significant need for effective therapeutic options, in addition to increased prevention, to halt the projected fourfold increase in youth T2D by 2050 and the consequences of heightened diabetes-related morbidity and mortality at younger ages.

Metabolic and glycemic sequelae of sleep disturbances in children and adults

The prevalence of obesity in adults and children has increased greatly in the past three decades, as have metabolic sequelae, such as insulin resistance and type 2 diabetes mellitus (T2DM). Sleep disturbances are increasingly recognized as contributors to this widespread epidemic in adults, and data are emerging in children as well. The categories of sleep disturbances that contribute to obesity and its glycemic co-morbidities include the following: (1) alterations of sleep duration, chronic sleep restriction and excessive sleep; (2) alterations in sleep architecture; (3) sleep fragmentation; (4) circadian rhythm disorders and disruption (i.e., shift work); and (5) obstructive sleep apnea. This article reviews current evidence supporting the contributions that these sleep disorders play in the development of obesity, insulin resistance, and T2DM as well as possibly influences on glycemic control in type 1 diabetes, with a special focus on data in pediatric populations.

Effect of metformin on sleep disorders in adolescent girls with polycystic ovarian syndrome

OBJECTIVE

Patients with polycystic ovarian syndrome (PCOS) have a high prevalence of sleep disorders. Metformin is an antidiabetic drug that may have a role in treatment of the manifestations of PCOS. The aim of this study was to assess the presence of sleep disorders in adolescent girls with PCOS and to study the effects of using metformin on sleep disorders in these girls.

METHODS

This study was carried out on 90 adolescent girls aging from 12 to 18 years who were divided into 3 equal groups: control untreated group, untreated PCOS group, and PCOS + metformin group. Body weight, height, body mass index, hirsutism score, fasting and postprandial blood glucose, fasting serum insulin, Homeostatic Model Assessment (HOMA) index, sleep disturbances scale, and Epworth sleepiness scale were measured.

RESULTS

Metformin administration resulted in significant decrease in the body weight, body mass index, hirsutism score, fasting and postprandial blood glucose, fasting serum insulin, HOMA index, sleep disturbances scale, and Epworth sleepiness scale compared to the untreated PCOS group.

CONCLUSION

Metformin can reduce the incidence of sleep disorders and excessive daytime sleepiness in adolescent girls with PCOS.

Obstructive sleep apnoea in obese adolescents and cardiometabolic risk markers

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

In paediatric patients, obstructive sleep apnoea is associated with adiposity, especially visceral adiposity. In adults, obstructive sleep apnoea is also associated with a higher prevalence of cardiovascular disease and type 2 diabetes. There are limited and conflicting paediatric studies examining the association between obstructive sleep apnoea and biomarkers of risk for cardiovascular disease and type 2 diabetes in youth.

WHAT THIS STUDY ADDS

Obstructive sleep apnoea is linked with greater cardiometabolic risk markers in obese adolescents. Fasting insulin and homeostasis model assessment-insulin resistance may be especially linked with obstructive sleep apnoea among obese male Hispanic adolescents. The relationship between obstructive sleep apnoea and cardiometabolic abnormalities in obese adolescents should be considered when evaluating patients found to have obstructive sleep apnoea.

BACKGROUND

Paediatric studies examining the association between obstructive sleep apnoea (OSA) and insulin sensitivity/cardiometabolic risk are limited and conflicting.

OBJECTIVE

This study aims to determine if cardiometabolic risk markers are increased among obese youth with obstructive sleep apnoea as compared with their equally obese peers without OSA.

METHODS

We performed a retrospective analysis of 96 patients (age 14.2 ± 1.4 years) who underwent polysomnography for suspected OSA. Fasting lipids, glucose, insulin and haemoglobin A1 c (HbA1 c) were performed as part of routine clinical evaluation. Patients were categorized into two groups by degree of OSA as measured by the apnoea-hypopnoea index (AHI): none or mild OSA (AHI < 5) and moderate or severe OSA (AHI ≥ 5).

RESULTS

Despite the similar degrees of obesity, patients with moderate or severe OSA had higher fasting insulin (P = 0.037) and homeostasis model assessment-insulin resistance (HOMA-IR [P = 0.0497]) as compared with those with mild or no OSA. After controlling for body mass index, there was a positive association between the AHI and log HOMA-IR (P = 0.005). There was a positive relationship between arousals plus awakenings during the polysomnography and fasting triglycerides.

CONCLUSIONS

OSA is linked with greater cardiometabolic risk markers in obese youth.

Are frequency and severity of sleep-disordered breathing in obese children and youth with and without type 2 diabetes mellitus different?

Obstructive sleep apnea (OSA) is a risk factor for insulin resistance and type 2 diabetes mellitus (T2DM) in adults. Data in children are limited. The aim was to study the frequency and severity of OSA and its association with cardiometabolic risk factors in obese children and adolescents with and without T2DM. In this prospective cross-sectional study, obese children and adolescents with and without T2DM underwent polysomnography and blood tests for fasting lipids, insulin, glucose, liver functions, and C-reactive protein. All participants completed a questionnaire on past and present sleep-disordered breathing (SDB). Results were compared between T2DM and obese non-diabetic controls matched for body mass index-standard deviation score (BMI-SDS) and also according to the glycemic status: T2DM, impaired glucose tolerance (IGT), and normal glycemic control. Eleven patients with T2DM (age 15.9 ± 3.6 years) and 30 BMI-SDS matched non-diabetic subjects (age 12.7 ± 3.0 years) were studied. Among the entire cohort, 45 % had a history of snoring, 26 % reported apneic episodes during sleep, and 65 % had daytime fatigue. There were no significant between-group differences in SDB history or abnormal polysomnographic results [apnea-hypopnea index (AHI) >5/h]. The percentage of subjects with AHI >5/h was 45.5 % in T2DM patients, 25 % in obese patients with IGT, and 18.2 % in obese patients without IGT, although the difference was not statistically significant (p = 0.25). Plasma C-reactive protein levels were related to both glycemic status and OSA severity. The severity of OSA in obese children and adolescents is unrelated to the presence of diabetes. OSA may play a minor role in the development and progression of T2DM in children and adolescents. Further studies in larger cohorts are required.

Metabolic alterations in children with obstructive sleep apnea

IMPORTANCE

The incidence of obesity is rising in the United States and has been linked to Obstructive Sleep Apnea (OSA) even in young children. Understanding the role that obesity and OSA play in alterations in metabolic variables that can lead to serious health issues is essential to the care and counseling of affected children.

OBJECTIVES

To evaluate the association of alterations in metabolic variables, including insulin resistance, to OSA in young, obese children.

DESIGN

Retrospective, case-control series.

SETTING

Tertiary care children's hospital.

PARTICIPANTS

Obese children aged 2-12 years who had undergone overnight polysomography and routine laboratory testing for lipid levels, fasting glucose, and insulin from January 1, 2006 to December 31, 2012 were identified from a TransMed Bio-Integration Suite and Epic's clarity database search.

RESULTS

A total of 76 patients were included for analysis. Forty-three (56.6%) were male, and the mean age was 8.3±2.5 years (range, 2.4-11.9 years). The mean body mass index (BMI) z score was 2.8±0.75 (range, 1.7-6.3), and all patients were obese (BMI z score>95th percentile). Twenty two patients (28.9%) had an apnea-hypopnea index (AHI) <1/h (no OSA), 27 (35.5%) an AHI≥1<5/h, 12 (15.8%) had an AHI ≥5<9.99/h, and 15 (19.7%) had an AHI≥10/h. There was no significant difference in total cholesterol, triglycerides, high and low density lipoprotein levels, systolic and diastolic blood pressure in those patients with or without OSA. Fasting insulin, blood glucose, and homeostasis model assessment (HOMA) were significantly higher in patients with OSA compared to those with no OSA (p<0.01). AHI correlated to alterations in insulin as well as glucose homeostasis on multivariate analysis. Results from logistic regression analysis showed that fasting insulin (p<0.01), and HOMA (p<0.01) predicted severe OSA independent of age, gender, and BMI z score in these patients.

CONCLUSION

Metabolic alterations in glucose and insulin levels, known to be associated with obesity and increased risk for cardiovascular disease, appear to relate to the severity of OSA in young children.

Predictors of obstructive sleep apnea severity in adenotonsillectomy candidates

STUDY OBJECTIVES

There is uncertainty over which characteristics increase obstructive sleep apnea syndrome (OSAS) severity in children. In candidates for adenotonsillectomy (AT), we evaluated the relationship of OSAS severity and age, sex, race, body mass index (BMI), environmental tobacco smoke (ETS), prematurity, socioeconomic variables, and comorbidities.

DESIGN

Cross-sectional screening and baseline data were analyzed from the Childhood Adenotonsillectomy Trial, a randomized, controlled, multicenter study evaluating AT versus medical management. Regression analysis assessed the relationship between the apnea hypopnea index (AHI) and risk factors obtained by direct measurement or questionnaire.

SETTING

Clinical referral setting.

PARTICIPANTS

Children, ages 5 to 9.9 y with OSAS.

MEASUREMENTS AND RESULTS

Of the 1,244 children undergoing screening polysomnography, 464 (37%) were eligible (2 ≤ AHI < 30 or 1 ≤ obstructive apnea index [OAI] < 20 and without severe oxygen desaturation) and randomized; 129 (10%) were eligible but were not randomized; 608 (49%) had AHI/OAI levels below entry criteria; and 43 (3%) had levels of OSAS that exceeded entry criteria. Among the randomized children, univariate analyses showed significant associations of AHI with race, BMI z score, environmental tobacco smoke (ETS), family income, and referral source, but not with other variables. After adjusting for potential confounders, African American race (P = 0.003) and ETS (P = 0.026) were each associated with an approximately 20% increase in AHI. After adjusting for these factors, obesity and other factors were not significant.

CONCLUSIONS

Apnea hypopnea index level was significantly associated with race and environmental tobacco smoke, highlighting the potential effect of environmental factors, and possibly genetic factors, on pediatric obstructive sleep apnea syndrome severity. Efforts to reduce environmental tobacco smoke exposure may help reduce obstructive sleep apnea syndrome severity.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov (#NCT00560859).

Morning blood pressure is associated with sleep quality in obese adolescents

OBJECTIVE

To examine relationships among blood pressure (BP), adiposity, and sleep quality with the use of overnight polysomnography in obese adolescents.

STUDY DESIGN

Overnight polysomnogram and morning BP measurements were performed in obese (body mass index [BMI] >95th percentile) nondiabetic adolescents (eligible age range 12-18 years, n = 49). Subjects were stratified into 2 groups, one with normal BP, and one with elevated BP, and demographic and clinical characteristics were compared between the groups. Multiple linear regression analysis was used to assess the effects of sleep quality on BP.

RESULTS

Participants (n = 27) had a normal morning BP, and 22 (44.9%) had elevated morning BP. There were no differences in age (P = .53), sex (P = .44), race (P = .58), or BMI (P = .56) between the 2 BP groups. The group with elevated BP spent shorter percentages of time in rapid eye movement (REM; P = .006) and slow-wave sleep (SWS; P = .024). Multiple linear regression analysis showed that a lower percentage of both REM and SWS was associated with increased morning BP after we adjusted for pubertal stage, sex, race, and BMI.

CONCLUSION

Lack of deeper stages of sleep, REM sleep, and SWS is associated with greater morning BP in obese adolescents, independent of BMI. Poor sleep quality should be considered in the work-up of obese youth with hypertension. Intervention studies are needed to evaluate whether improving the quality of sleep will decrease BP elevation.

Impact of sleep-disordered breathing on myocardial damage and metabolism in patients with chronic heart failure

Sleep-disordered breathing (SDB) has a critical association with mortality and morbidity of patients with chronic heart failure (CHF). Troponin T is a marker of ongoing myocardial damage and predicts adverse clinical outcomes in patients with CHF. Carnitine plays an important role in the utilization of fatty acids in the myocardium. It has been reported that myocardial carnitine levels decrease in the failing heart. We hypothesized that plasma troponin T and carnitine are increased due to the leakage from damaged cardiomyocytes or the alteration of myocardial metabolism in CHF patients with SDB. We examined the relation of plasma troponin T and carnitine levels with severity of SDB in CHF. We used portable sleep monitor and measured the apnea-hypopnea index (AHI), plasma levels of high-sensitive troponin T and carnitine in 131 CHF patients. These patients were divided into three groups based on AHI: group A (None-mild SDB AHI < 15/h, n = 45), group B (Moderate SDB 15 ≤ AHI < 30/h, n = 32) and group C (Severe SDB AHI ≥ 30/h, n = 54). Levels of high-sensitive troponin T and plasm total carnitine were significantly higher in group C than in groups A and B [high-sensitive troponin T; group A 0.009 (0.005-0.016), group B 0.012 (0.006-0.021), group C 0.021 (0.011-0.039) ng/ml, total carnitine; group A 61.0 ± 15.1, group B 65.0 ± 13.5, group C 73.3 ± 17.5 μmol/l, P < 0.01 vs. group A and P < 0.05 vs. group B, respectively]. Furthermore, in the multiple regression analysis, the independent factors to determine plasma levels of log (high-sensitive troponin T) were high-sensitive C-reactive protein and AHI, and the independent factors to determine plasma levels of carnitine were glomerular filtration rate and AHI. The present study suggests that SDB is associated with latent myocardial damage and alteration of myocardial carnitine metabolism in patients with CHF, presented by higher circulating troponin T and carnitine levels.

Depressive symptoms and metabolic markers of risk for type 2 diabetes in obese adolescents

OBJECTIVE

Although higher rates of depression are found among individuals with type 2 diabetes, it remains unknown if the presence of depressive symptoms is associated with heightened metabolic risk for the development of type 2 diabetes among youth. The objective of this study was to evaluate whether depressive symptoms in obese adolescents are associated with impaired β-cell function relative to insulin sensitivity [oral disposition index (oDI)] and/or dysglycemia or prediabetes, predictors of type 2 diabetes development.

RESEARCH DESIGN AND METHODS

Fasting and oral glucose tolerance test (OGTT)-derived indices of glucose tolerance, insulin sensitivity, secretion, and oDI were evaluated in obese youth (n = 56, age 15.0 ± 1.6 yr, 68% female). The Children's Depression Inventory was utilized to determine depressive symptomatology.

RESULTS

Despite no association between depressive symptoms and measures of adiposity, youth with higher depressive symptoms had (i) significantly higher fasting and stimulated glucose levels (13% higher glucose area under the OGTT curve), (ii) ∼50% lower oDI, and (iii) a 50% frequency of prediabetes.

CONCLUSIONS

These data point to an important relationship between depressive symptoms and a heightened metabolic risk for type 2 diabetes in obese adolescents, including prediabetes and impairment in β-cell function relative to insulin sensitivity. While the directionality of these relationships is unknown, it should be determined if treating one disorder improves the other or vice versa.

Pediatric obesity, metabolic syndrome, and obstructive sleep apnea syndrome

The prevalence of obesity in the pediatric population has dramatically increased in the last 30 years. While the adverse health effects of obesity have long been recognized in adults, many of these complications are now understood to begin in early childhood. Obese children and adolescents are significantly more likely than their peers of healthy weight to suffer from obstructive sleep apnea and metabolic syndrome. In turn, affected individuals may experience myriad serious clinical sequelae; neuro-cognitive, psychiatric, cardiovascular, and endocrinologic complications have each been extensively documented. Thus, the spectrum of obesity-related disease represents a serious but preventable threat to personal and family wellness; additionally, it is a source of considerable health care expenditure and represents a national and international health crisis. The optimal care of these patients will be best achieved through the pediatric health care provider's timely recognition of these clinical problems and knowledge of appropriate intervention strategies.

Relationship between body fat distribution and upper airway dynamic function during sleep in adolescents

INTRODUCTION

The obstructive sleep apnea syndrome (OSAS) is associated with increased visceral adipose tissue (VAT) in adults; however, few studies have evaluated VAT in relation to upper airway function in adolescents. We hypothesized that increased neck circumference (NC) and VAT would be associated with increased upper airway collapsibility.

METHODS

Adolescents (24 obese patients with OSAS, 22 obese control patients, and 29 lean control patients) underwent abdominal magnetic resonance imaging, and measurement of upper airway pressure-flow relationships in the activated and hypotonic upper airway states.

RESULTS

Patients with OSAS had a greater activated slope of the pressure-flow relationship (SPF) than control groups (P < 0.001), whereas hypotonic SPF was greater in both obese groups compared with lean control patients (P = 0.01). NC and VAT were greater in obese control patients and those with OSAS than in lean control patients (P < 0.001), but did not differ between obese patients with OSAS and obese control patients. In lean control patients and those with OSAS, increased NC was associated with increased activated SPF, whereas in obese control patients it was associated with decreased activated SPF (P = 0.03). In contrast, increased NC was associated with increased hypotonic SPF in all groups (P < 0.001). There was no significant effect of VAT on either activated or hypotonic SPF for any of the three groups.

CONCLUSIONS

Increased neck circumference was associated with increased upper airway collapsibility in adolescents in the hypotonic but not activated state. These data suggest that obese adolescents without OSAS, despite a narrowed upper airway from adipose tissue, are protected from developing OSAS by upper airway neuromotor activation. Neither neck circumference nor visceral adipose tissue is useful in predicting upper airway collapsibility in obese adolescents.

Chemoreceptors, baroreceptors, and autonomic deregulation in children with obstructive sleep apnea

Obstructive sleep apnea (OSA) is highly prevalent sleep disorder of breathing in both adults and children that is fraught with substantial cardiovascular morbidities, the latter being attributable to a complex interplay between intermittent hypoxia (IH), episodic hypercapnia, recurrent large intra-thoracic pressure swings, and sleep disruption. Alterations in autonomic nervous system function could underlie the perturbations in cardiovascular, neurocognitive, immune, endocrine and metabolic functions that affect many of the patients suffering from OSA. Although these issues have received substantial attention in adults, the same has thus far failed to occur in children, creating a quasi misperception that children are protected. Here, we provide a critical overview of the evidence supporting the presence of autonomic nervous system (ANS) perturbations in children with OSA, draw some parallel assessments to known mechanisms in rodents and adult humans, particularly, peripheral and central chemoreceptor and baroreceptor pathways, and suggest future research directions.

Insulin resistance in type 2 diabetic youth

PURPOSE OF REVIEW

This review focuses on recent literature on insulin resistance in youth with type 2 diabetes mellitus (T2DM). Insulin resistance is associated with a variety of cardiometabolic problems leading to increased morbidity and mortality across the lifespan.

RECENT FINDINGS

Functional pancreatic β-cell changes play a role in the transition from obesity to impaired glucose tolerance (IGT). Insulin resistance drives islet cell upregulation, manifested by elevated glucagon and c-peptide levels, early in the transition to IGT. Surrogate measurements of insulin resistance and insulin secretion exist but their accuracy compared to clamp data is imperfect. Recent large longitudinal studies provide detailed information on the progression from normoglycemia to T2DM and on the phenotype of T2DM youth. Defining prediabetes and T2DM remains a challenge in youth. Lifestyle interventions do not appear as effective in children as in adults. Metformin remains the only oral hypoglycemic agent approved for T2DM in youth.

SUMMARY

New insights exist regarding the conversion from insulin resistance to T2DM, measurement of insulin resistance and phenotypes of insulin resistance youth, but more information is needed. Surrogate measurements of insulin resistance, additional treatment options for insulin resistance and individualization of treatment options for T2DM adolescents in particular require further investigation.

Relationships among obstructive sleep apnea, anthropometric measures, and neurocognitive functioning in adolescents with severe obesity

OBJECTIVE

To explore associations between measures of obstructive sleep apnea (OSA) and sleep quality, anthropometrics, and neurocognitive functioning in severely obese adolescents.

STUDY DESIGN

This was a cross-sectional pilot study performed at an academic medical center in 37 severely obese (body mass index [BMI] >97th percentile) adolescents. Study evaluations included polysomnography, BMI, waist circumference, and standardized neurocognitive tests to assess memory, executive functioning, psychomotor efficiency, academic achievement, and an approximation of full-scale IQ. Outcome data were evaluated categorically, based on clinical criteria for the diagnosis of OSA, and continuously to quantify associations between sleep parameters, anthropometrics, and neurocognitive test results.

RESULTS

Sleep fragmentation and poorer sleep quality were associated with reduced psychomotor efficiency, poorer memory recall, and lower scores on standardized academic tests. Having evidence of OSA was associated with lower math scores, but not with other neurocognitive measures. BMI and waist circumference were negatively associated with oxygen saturation.

CONCLUSION

Our pilot study findings suggest that sleep fragmentation and poorer sleep quality have implications for neurocognitive functioning in obese adolescents. The epidemic of childhood obesity has dire implications, not only for increasing cardiometabolic pathology, but also for possibly promoting less readily apparent neurologic alterations associated with poor sleep quality.

Sleep architecture and glucose and insulin homeostasis in obese adolescents

OBJECTIVE

Sleep deprivation is associated with increased risk of adult type 2 diabetes mellitus (T2DM). It is uncertain whether sleep deprivation and/or altered sleep architecture affects glycemic regulation or insulin sensitivity or secretion. We hypothesized that in obese adolescents, sleep disturbances would associate with altered glucose and insulin homeostasis.

RESEARCH DESIGN AND METHODS

This cross-sectional observational study of 62 obese adolescents took place at the Clinical and Translational Research Center and Sleep Laboratory in a tertiary care children's hospital. Subjects underwent oral glucose tolerance test (OGTT), anthropometric measurements, overnight polysomnography, and frequently sampled intravenous glucose tolerance test (FSIGT). Hemoglobin A(1c) (HbA(1c)) and serial insulin and glucose levels were obtained, indices of insulin sensitivity and secretion were calculated, and sleep architecture was assessed. Correlation and regression analyses were performed to assess the association of total sleep and sleep stages with measures of insulin and glucose homeostasis, adjusted for confounding variables.

RESULTS

We found significant U-shaped (quadratic) associations between sleep duration and both HbA(1c) and serial glucose levels on OGTT and positive associations between slow-wave sleep (N3) duration and insulin secretory measures, independent of degree of obesity, pubertal stage, sex, and obstructive sleep apnea measures.

CONCLUSIONS

Insufficient and excessive sleep was associated with short-term and long-term hyperglycemia in our obese adolescents. Decreased N3 was associated with decreased insulin secretion. These effects may be related, with reduced insulin secretory capacity leading to hyperglycemia. We speculate that optimizing sleep may stave off the development of T2DM in obese adolescents.

Screening for sleep-disordered breathing and excessive daytime sleepiness in adolescent girls with polycystic ovarian syndrome

OBJECTIVE

To determine the prevalence and clinical and metabolic correlates of sleep-disordered breathing (SDB) and excessive daytime sleepiness (EDS) in adolescent girls with polycystic ovarian syndrome (PCOS).

STUDY DESIGN

Standardized questionnaires were administered to participants with PCOS and age-, sex-, ethnicity-, and body mass index (BMI) z score-matched controls. Medical records were reviewed for anthropometric and metabolic data.

RESULTS

We studied 103 participants with PCOS (16.9 ± 1.5 years) and 90 controls (16.8 ± 1.7 years). Compared with controls, girls with PCOS had a higher prevalence of SDB (45.6% vs 27.8%; P = .01) and EDS (54.4% vs 35.6%; P < .01). Within PCOS, those with SDB had higher BMI z score (2.1 ± 0.5 vs 1.7 ± 0.6; P < .01), higher homeostatic model assessment index (5.1 ± 2.3 vs 4.1 ± 3.5; P < .01), and higher prevalence of the metabolic syndrome (MetS) (42.6% vs 16.1%; P = .003) compared with those without SDB. Similarly, participants with PCOS and EDS had a higher BMI z score (2.0 ± 0.6 vs 1.7 ± 0.6; P = .03), higher homeostatic model assessment index (5.1 ± 2.9 vs 3.8 ± 3.1; P = .01), and higher rate of MetS (39.3% vs. 14.9%; P < .01) compared with those without EDS. MetS was independently associated with SDB (OR, 3.2; 95% CI, 1.0-10.1) and EDS (OR, 4.5; 95% CI, 1.2-16).

CONCLUSIONS

SDB and EDS are highly prevalent in adolescent girls with PCOS compared with matched controls. The MetS is independently associated with SDB and EDS in this group.