Obesity in children with different risk factors for obstructive sleep apnea: a community-based study

Risk Factors of Obstructive Sleep Apnea (OSA) in Pediatric Patients: A Systematic Review and Meta-analysis

INTRODUCTION

This review aimed to assess the risk factors of Obstructive Sleep Apnea (OSA) in pediatric children, a common condition with serious long-term sequela.

METHODS

PubMed, CENTRAL, Scopus, and Google Scholar were searched using the keywords "Apnea", "Obstructive Sleep" OR "Obstructive Sleep Apnea Syndrome" AND "Child" OR "Children" OR "Pediatrics". Data from 35 studies involving 497,688 pediatric patients diagnosed with OSA using polysomnography were reviewed. Risk factors examined included sex, obesity, neck circumference, tonsillar/adenoid hypertrophy, respiratory infections, nasal stenosis, parental OSA/smoking, ethnicity, preterm birth, and breastfeeding history. Relative Risk (RR) with 95% Confidence Intervals (95% CI) were calculated, using Cochrane Q and I² statistics to estimate heterogeneity.

RESULTS

Tonsillar hypertrophy (RR = 3.55), adenoid hypertrophy (RR = 1.63), respiratory tract infection (RR = 2.59), obesity (RR = 1.74), and family history of OSA (RR = 3.03) were significantly associated with pediatric OSA. White ethnicity was protective (RR = 0.77).

DISCUSSION

Recognizing these risk factors aids in early diagnosis and treatment of pediatric OSA.

The Role of Telemedicine in Children with Obstructive Sleep Apnea Syndrome (OSAS): A Review of the Literature

The advent of telemedicine marked a significant turning point in the healthcare landscape, introducing a revolutionary approach to the delivery of medical care. Digital technologies easily connect health professionals and patients, overcoming geographical and temporal barriers. Telemedicine has been used for sleep disorders including obstructive sleep apnea syndrome (OSAS) since the mid-1990s. In adult patients with OSAS, telemedicine is helpful both for consultation and diagnosis, the latter obtained through remote recordings of oxygen saturation and further parameters registered with telemonitored respiratory polygraphy or polysomnography. Remote monitoring can be used to follow up the patient and verify adherence to daily treatments including continuous positive airway pressure (CPAP). In children, studies on the role of telemedicine in OSAS are scarce. This narrative review aims to describe the application of telemedicine in children with obstructive sleep apnea syndrome (OSAS), assessing its advantages and disadvantages. In patients with OSA, telemedicine is applicable at every stage of patient management, from diagnosis to treatment monitoring also in pediatric and adolescent ages. While telemedicine offers convenience and accessibility in healthcare delivery, its application in managing OSAS could be associated with some disadvantages, including limitations in physical examination, access to diagnostic tools, and education and counseling; technology barriers; and privacy concerns. The adoption of a hybrid approach, integrating both in-office and virtual appointments, could effectively meet the needs of children with OSAS. However, more studies are needed to fully assess the effectiveness and safety of telemedicine in the pediatric population.

Associations of early life and childhood risk factors with obstructive sleep apnoea in middle-age

BACKGROUND AND OBJECTIVE

Early-life risk factors for obstructive sleep apnoea (OSA) are poorly described, yet this knowledge may be critical to inform preventive strategies. We conducted the first study to investigate the association between early-life risk factors and OSA in middle-aged adults.

METHODS

Data were from population-based Tasmanian Longitudinal Health Study cohort (n = 3550) followed from 1st to 6th decades of life. Potentially relevant childhood exposures were available from a parent-completed survey at age 7-years, along with previously characterized risk factor profiles. Information on the primary outcome, probable OSA (based on a STOP-Bang questionnaire cut-off ≥5), were collected when participants were 53 years old. Associations were examined using logistic regression adjusting for potential confounders. Analyses were repeated using the Berlin questionnaire.

RESULTS

Maternal asthma (OR = 1.5; 95% CI 1.1-2.0), maternal smoking (OR = 1.2; 1.05, 1.5), childhood pleurisy/pneumonia (OR = 1.3; 1.04, 1.7) and frequent bronchitis (OR = 1.2; 1.01, 1.5) were associated with probable OSA. The risk-factor profiles of 'parental smoking' and 'frequent asthma and bronchitis' were also associated with probable OSA (OR = 1.3; 1.01, 1.6 and OR = 1.3; 1.01-1.9, respectively). Similar associations were found for Berlin questionnaire-defined OSA.

CONCLUSIONS

We found novel temporal associations of maternal asthma, parental smoking and frequent lower respiratory tract infections before the age of 7 years with adult OSA. While determination of their pathophysiological and any causal pathways require further research, these may be useful to flag the risk of OSA within clinical practice and create awareness and vigilance among at-risk groups.

Effect of Obesity on the Respiratory Parameters in Children with Obstructive Sleep Apnea Syndrome

The aim of the study was to investigate how obesity can influence sleep respiratory parameters in obstructive sleep apnea syndrome (OSAS) in children.

METHODS

The study analyzes 56 Caucasian children and adolescents aged 11 ± 2.79 years with a BMI > 5th percentiles and a PSQ value ≥ 0.33. Children were divided into Obesity Group (OG) with BMI ≥ 95th and Control Group (CG) with 5th < BMI > 95th percentile. All selected children underwent PG. Respiratory parameters AHI (Apnea-Hypopnea Index), SaO2 (Saturation of Oxygen), ODI (Oxygen Desaturation Index), and Nadir (the lowest value of SaO2 registered during PG) were extracted from the PG. AHI was used to divide the severity of OSAS into four levels: snoring (AHI ≤ 1), mild (AHI > 1 and ≤5), moderate (AHI > 5 and <10), and severe (AHI ≥ 10).

RESULTS

The comparison analysis between the OG and CG showed a statistical significance only for ODI (p = 0.02). A statistically significant correlation between BMI and AHI (r = 0.02), SaO2 (r = 0.01), and Nadir O2 (r = 0.02) was found.

CONCLUSIONS

There was no strong correlation between obesity and OSAS, but a positive association was found between BMI and AHI severity.

Food Intake and Sleep Disorders in Children and Adolescents with Obesity

Over the last few decades, numerous scientific studies have investigated the possible association between sleep duration and adiposity during childhood, since it has been reported that sleep deprivation causes a related increase in caloric intake. Even though the underlying pathogenetic mechanisms are still under study and not completely known, the effect of dietetic habits and nutrient intake on sleep quality and patterns has been reported. The aim of this study is to explore the intricate interplay between food intake/diet patterns and pediatric sleep disturbances in children and adolescents with obesity, emphasizing the importance of not underestimating this aspect in the prevention and treatment of this complex disease. Recent evidence supports a high correlation between specific diet patterns and foods with sleep disturbances in children at all ages. Diets rich in fiber, fruit, vegetables, and anti-inflammatory nutrients and low in saturated fats seem to promote better sleep quality. Sleep disturbances are, in turn, risk factors for the development of obesity. Therefore, food strategies should be applied to counteract this harmful process. Unraveling the complex links between dietary habits, sleep patterns, and obesity is essential for developing effective strategies to combat this critical public health issue.

Is There an Association between Viral Infections and Risk for Pediatric Obstructive Sleep Apnea? A Systematic Review

(1) Background: Obstructive sleep apnea (OSA) affects approximately 1% to 5% of children. To date, the main pathophysiological factor is adenotonsillar tissue hypertrophy. As many respiratory viruses can persist in secondary lymphoepithelial organs after upper airway infection, the objective of this systematic review was to investigate the link between history of viral infections and the risk of pediatric OSA. (2) Methods: Corresponding references were searched electronically (PubMed [MEDLINE], Cochrane Library and Scopus) until 21 November 2022. Prospective or retrospective cohorts, evaluating the children suffering from OSA with history of viral infections and comparing them with children with no history of viral infections written in English, were included. Four independent reviewers selected studies, extracted data, and evaluated the risk of bias using ROBINS-I. (3) Results: Of 1027 potentially eligible articles, four studies (one retrospective, two prospective cohorts and one case-control) were included. (4) Conclusions: Exposure to lower airway infections may precede the diagnosis of pediatric OSA suggesting that respiratory viruses may play a mechanical role in the development of pediatric OSA. Further research is required to improve our understanding of the role of viral infections. Registration: PROSPERO CRD awaiting.

Craniofacial and upper airway morphological characteristics associated with the presence and severity of obstructive sleep apnea in Chinese children

Objectives

To identify craniofacial and upper airway morphological characteristics associated with the presence and severity of obstructive sleep apnea (OSA) in children.

Methods

This study consisted of 82 OSA children and 77 controls (age 5-10 years). All subjects underwent cephalograms and were divided into a 5-7 age group and an 8-10 age group. Cephalometric variables were compared between OSA children and controls, and hierarchical regression analysis was performed to examine the relationship between cephalometric variables and OSA severity [expressed by the obstructive apnea-hypopnea index (OAHI)] in different age groups.

Results

Increased A/N ratio, narrowed posterior airway space, decreased SNA and SNB angles, and shortened ramus height were observed among OSA children in different age groups. In the 5-7 age group, the A/N ratio and a lower gonial angle explained 40.0% and 14.7% of the variance in the OAHI, respectively. In the 8-10 age group, the BMI z-score and A/N ratio explained 25.2% and 6.6% of the variance in the OAHI, followed by a lower gonial angle and the hyoid-retrognathion distance (19.1% in total).

Conclusions

Adenoid hypertrophy was a major factor associated with OSA in preschool children, whereas obesity replaced adenoid hypertrophy as the main contributor to OSA in late childhood. Several craniofacial skeletal variables such as the SNB angle, ramus height, lower gonial angle, and hyoid position are also associated with the presence and/or severity of OSA, which could be used to help recognize children at a higher risk for OSA.

Sleep disordered breathing and its relation to stroke and pulmonary hypertension in children with sickle cell disease: a single-center cross-sectional study

Sleep disordered breathing (SDB) is a common underdiagnosed sequela of sickle cell disease (SCD) that has been linked to the frequency of vaso-occlusive crises. To determine the frequency of SDB in children with SCD and its association to SCD-related complications, thirty children and adolescents with SCD at their steady state underwent clinical, laboratory, and radiological assessment using transcranial duplex (TCD) and echo assessment of tricuspid regurge velocity (TRV). All participants had an overnight polysomnography after completing the modified STOP-Bang questionnaire. The mean age of the studied cohort was 10.2 years, with male: female ratio 1.7:1. Six children (20%) had high-risk for obstructive sleep apnea (OSA), while nine (30%) were at intermediate risk. Sleep apnea defined as apnea (AHI) > 1 event/hour was found among 18/30 (60%) subjects (14 males and 4 females). Children with AHI > 5 (moderate to severe OSA) had significantly higher TRV (p = 0.007) and left MCA flow velocity (p = 0.049) when compared to those with AHI < 5. Children with AHI > 5 were at higher risk of OSA according to the modified STOP-Bang questionnaire (p = 0.02). AHI positively correlated with TRV (r = 0.53, p = 0.003), right MCA flow velocity (r = 0.45, p = 0.013), and left MCA flow velocity (r = 0.55, p = 0.002), and negatively correlated to BMI-SDS (r =  - 0.48, p = 0.008). The high frequency of OSA in the studied cohort with SCD and its association with increasing risk of PH and TCD changes highlights the importance of early detection and management of OSA in children with SCD.

Polysomnography findings in preschool children with obstructive sleep apnea are affected by growth and developmental level

OBJECTIVE

We investigated the effect of growth and development level on polysomnography results in preschool children with obstructive sleep apnea (OSA).

METHODS

Preschool children (ages 3-6) with symptoms of snoring and were diagnosed with OSA by polysomnography in the sleep center were selected as the research object. They were split into three groups based on their growth rates: restricted, normal, and excessive. Sleep structure, respiratory events, and oxygenation index were compared between the three groups.

RESULTS

A total of 183 (111 boys and 72 girls) preschool children were enrolled. There were 26 cases in the growth restricted group, 112 cases in the normal growth group, and 45 cases in the overgrowth group. The weight and Body Mass Index (BMI) of children in the growth restricted and overgrowth groups were significantly different from those in the normal group. In terms of sleep structure, the sleep efficiency of the growth restricted group was poorer than that of the normal group. For sleep breathing events, the growth restricted group showed a greater apnea-hypopnea index (AHI), obstructive apnea hypopnea index (OAHI), hypoventilation index, and more hypoventilation than the normal group. In terms of oxygenation, the difference in degree of hypoxia between the three groups was statistically significant, and the overgrowth group had lower minimum oxygen saturation during the rapid eye movement phase than the normal group, as well as a quicker mean heart rate.

CONCLUSIONS

OSA is more likely in preschool-aged children with stunted or overgrown growth than in children with OSA alone, and the more severe the disorder, especially when accompanied with stunted growth.

Progression of Obstructive Sleep Apnea Syndrome in Pediatric Patients with Prader-Willi Syndrome

Obstructive sleep apnea syndrome (OSAS) is one of the most common comorbidities in patients with Prader-Willi syndrome (PWS) and causes significant consequences. This observational study was conducted to investigate the progression of OSAS in pediatric patients with PWS, who had not undergone upper airway surgery, through a longitudinal follow-up of their annual polysomnography results. Annual body mass index (BMI), BMI z-score, sleep efficiency and stages, central apnea index (CAI), obstructive apnea-hypopnea index (OAHI), and oxygen saturation nadir values were longitudinally analyzed. At enrollment, of 22 patients (10 boys and 12 girls) aged 11.7 ± 3.9 years, 20 had OSAS. During the 4-year follow-up, only two patients had a spontaneous resolution of OSAS. The average BMI and BMI z-score increased gradually, but CAI and OAHI showed no significant differences. After statistical adjustment for sex, age, genotype, growth hormone use, and BMI z-score, OAHI was associated with the BMI z-score and deletion genotype. In conclusion, OSAS is common in patients with PWS, and rarely resolved spontaneously. Watchful waiting may not be the best OSAS management strategy. Weight maintenance and careful selection of surgical candidates are important for OSAS treatment in patients with PWS.

Age- and gender-related characteristics in pediatric obstructive sleep apnea

BACKGROUND

Age and gender disparities in polysomnographic findings in children are not well understood.

OBJECTIVE

This study determined age and gender-related characteristics in pediatric obstructive sleep apnea (OSA).

METHOD

Retrospectively, data were collected. We analyzed polysomnographic data in the following age groups: 3-6 years (n = 681), 6-9 years (n = 553), 9-12 years (n = 297), 12-15 years (n = 200), and 15-18 years (n = 111).

RESULTS

A total of 1842 children were included (mean age: 8.0 years; boys: 67%; obesity: 21%). The apnea-hypopnea index (AHI) gradually increased with age (3-6, 6-9, 9-12, 12-15, and 15-18 years groups: 6.2, 5.9, 6.5, 8.1, and 9.9 event/h, respectively; p trend = 0.002). In all age groups, boys had a higher AHI than girls (7.8 vs. 4.1 events/h, p < 0.001). Children with obesity had a higher AHI than those without (12.9 vs. 4.9 events/h, p < 0.001). The mean AHI in the boys increased with age (3-6 to 15-18 years groups: 7.0-13.6 events/h, respectively; p trend < 0.001), whereas the mean AHI in the girls was not significantly different between ages (p trend = 0.492). In moderation analyses, gender was a moderator in the association between obesity and AHI, and the association between age and AHI during 12-15 and 15-18 years of ages.

CONCLUSION

Male gender and obesity increase risk of OSA. Regarding age disparities, this study discovered a higher AHI in male adolescents than in young boys.

Polysomnographic comparison of sleep in children with obesity and normal weight without suspected sleep-related breathing disorder

Short sleep and obstructive apneas/hypopneas have been shown to be associated with childhood obesity. Still, few studies have compared sleep in children with obesity, without suspected sleep disordered breathing and normal weight peers by objective sleep measures and compared results with subjective parent assessment of sleep. Children with obesity aged 7-13 years (N = 44) and a matched group of normal weight children (N = 42) completed clinical polysomnography (Embla A10 Recording System). Parents scored their children's sleep on the Children's Sleep Habits Questionnaire (CSHQ). Mann-Whitney U tests were used to compare groups. There was a higher obstructive apnea/hypopnea index (AHI) (median obesity = 1.20 vs. median normal  = 0.66; z = -1.33, U = 560.50, p = 0.002) and number of oxygen desaturation events per hour (median obesity = 0.7 vs. median normal  = 0.2; z = -3.45, U = 402.50, p = 0.001) in the children with obesity compared to children with normal weight. The children with obesity had a significantly longer sleep duration (median obesity 8:50 h = vs. median normal = 8:32 h; z = -2.05, U = 687.00, p = 0.041), longer stage N2 sleep (median obesity = 87 min vs. median normal = 52 min; z = -2.87, U = 576.50, p = 0. 004) and shorter REM sleep (median obesity = 94 min vs. median normal = 121 min; z = 5.05, U = 1477.00, p ≤ .001). No differences were observed for time in sleep stage N1 and N3, wake time after sleep onset or the total arousal index . Further, no group differences were found on the CSHQ sleep-disordered breathing sub-scale (p = 0.399). The children with obesity demonstrated significantly more mild to moderate sleep disordered breathing than children with normal weight, although this was not corroborated by parent report.

Does sleep-disordered breathing add to impairments in academic performance and brain structure usually observed in children with overweight/obesity?

Approximately 4-11% of children suffer from sleep-disordered breathing (SDB), and children with obesity are at increased risk. Both obesity and SDB have been separately associated with poorer brain health, yet whether SDB severity affects brain health in children with obesity remains unanswered. This study aimed to examine associations of SDB severity with academic performance and brain structure (i.e., total brain and gray and white matter volumes and gray matter volume in the hippocampus) in children with overweight/obesity. One hundred nine children aged 8-12 years with overweight/obesity were included. SDB severity and its subscales (i.e., snoring, daytime sleepiness, and inattention/hyperactivity) were evaluated via the Pediatric Sleep Questionnaire (PSQ), and academic performance was evaluated with the Woodcock-Muñoz standardized test and school grades. Brain structure was assessed by magnetic resonance imaging. SDB severity was not associated with academic performance measured by the standardized test (all |β|> 0.160, P > 0.076), yet it was associated with the school grade point average (β = -0.226, P = 0.007) and natural and social science grades (β = -0.269, P = 0.024). Intention/hyperactivity seemed to drive these associations. No associations were found between SDB severity and the remaining school grades (all β < -0.188, P > 0.065) or brain volumes (all P > 0.05).

CONCLUSION

Our study shows that SDB severity was associated with lower school grades, yet it was not associated with the standardized measurement of academic performance or with brain volumes in children with overweight/obesity. SDB severity may add to academic problems in children beyond the effects contributed by overweight/obesity status alone.

WHAT IS KNOWN

• Sleep-disordered breathing (SDB) may affect brain structure and academic performance in children. • Children with overweight/obesity are at higher risk for the development of SDB, yet the comorbid obesity-SDB relationship with brain health has not been investigated thus far.

WHAT IS NEW

• To our knowledge, this is the first study examining the associations of comorbid obesity-SDB severity with brain volumes and academic performance in children. • SDB symptoms may adversely affect academic performance at school in children with overweight/obesity, beyond the effects of weight status alone.

Lower respiratory tract infections in early life are associated with obstructive sleep apnea diagnosis during childhood in a large birth cohort

STUDY OBJECTIVES

Several birth cohorts have defined the pivotal role of early lower respiratory tract infections (LRTI) in the inception of pediatric respiratory conditions. However, the association between early LRTI and the development of obstructive sleep apnea (OSA) in children has not been established.

METHODS

To investigate whether early LRTIs increase the risk of pediatric OSA, we analyzed clinical data in children followed during the first 5 years in the Boston Birth Cohort (n = 3114). Kaplan-Meier survival estimates and Cox proportional hazards models adjusted by pertinent covariates were used to evaluate the risk of OSA by the age of 5 years between children with LRTI during the first 2 years of life in comparison to those without LRTI during this period.

RESULTS

Early life LRTI increased the risk of pediatric OSA independently of other pertinent covariates and risk factors (hazard ratio, 1.53; 95% CI, 1.15 to 2.05). Importantly, the association between LRTI and pediatric OSA was limited to LRTIs occurring during the first 2 years of life. Complementarily to this finding, we observed that children who had severe respiratory syncytial virus bronchiolitis during infancy had two times higher odds of OSA at 5 years in comparison with children without this exposure (odds ratio, 2.09; 95% CI, 1.12 to 3.88).

CONCLUSIONS

Children with severe LRTIs in early life have significantly increased risk of developing OSA during the first 5 years of life. Our results offer a new paradigm for investigating novel mechanisms and interventions targeting the early pathogenesis of OSA in the pediatric population.

Butyric acid alleviated chronic intermittent hypoxia-induced lipid formation and inflammation through up-regulating HuR expression and inactivating AMPK pathways

To investigate whether butyric acid could alleviate chronic intermittent hypoxia (CIH)-induced lipid formation in human preadipocytes-subcutaneous (HPA-s) through accumulation of human antigen R (HuR) and inactivation of AMP-activated protein kinase (AMPK) pathway, HPA-s were obtained and divided into three groups: Control group: cells were cultured under normal conditions; CIH group: cells were cultured in a three-gas incubator (10% O₂); Butyric acid group: 10 mmol/l butyric acid added into cell culture medium. HuR-siRNA was futher transfected into CIH group for verification the function of HuR. Oil Red O was implemented for observation of lipid droplets within cells. Cell Counting Kit-8 (CCK8) assay was used for detecting cell viability. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labeling (TUNEL) assay as well as flow cytometry analysis was employed for determining cell apoptosis. Western blotting was used for measurement of protein expression levels. RT-qPCR analysis was used for detecting mRNA expression. CIH treatment increased adipocytes proliferation, while butyric acid inhibited cell proliferation and promoted cell apoptosis. The treatment of butyric acid in CIH group down-regulated expression of inflammatory factors and increased cell apoptotic rate. Butyric acid treatment increased HuR expression in both cytoplasm and nucleus and decreased the level of p-AMPK and p-ACC, while transfection of AMPK activator or HuR-siRNA would down-regulate HuR expression. Moreover, butyric acid alleviated CIH-induced cell proliferation, lipid formation and inflammatory status and promoted cell apoptosis through regulating related genes including p21, PPARγ, C/EBPa, IL-1β, IL-6, TLR4, caspase-8 and caspase-3. In conclusion, butyric acid could alleviate CIH-induced inflammation, cell proliferation and lipid formation through accumulation of HuR and inactivation of AMPK pathway.

Comparison of Frequency and Severity of Sleep-Related Breathing Disorders in Children with Simple Obesity and Paediatric Patients with Prader-Willi Syndrome

Sleep-related breathing disorders (SRBDs) can be present in children with simple obesity and with Prader–Willi syndrome (PWS) and influence an individual diagnostic and treatment approach. We compared frequency and severity of SRBDs in children with simple obesity and with PWS, both without and on recombinant human growth hormone (rhGH) treatment, and correlation of SRBDs with insulin resistance tests. A screening polysomnography-polygraphy (PSG), the oral glucose tolerance test (OGTT) and homeostasis model assessment of insulin resistance (HOMA-IR) were analysed in three groups of patients—with simple obesity (group 1, n = 30, mean age 14.2 years), patients with PWS without the rhGH therapy (group 2, n = 8, mean age 13.0 years) and during the rhGH treatment (group 3, n = 17, mean age 8.9 years). The oxygen desaturation index (ODI) was significantly higher in groups 2 and 3, compared to group 1 (p = 0.00), and hypopnea index (HI) was higher in group 1 (p = 0.03). Apnea–hypopnea index (AHI) and apnea index (AI) results positively correlated with the insulin resistance parameters in groups 1 and 3. The PSG values worsened along with the increasing insulin resistance in children with simple obesity and patients with PWS treated with rhGH that may lead to a change in the patients’ care.

Efficacy of a Pediatric Sleep Questionnaire for the Diagnosis of Obstructive Sleep Apnea in Children

BACKGROUND

Obstructive sleep apnea (OSA) is a source of significant morbidity in children. Polysomnography (PSG), the gold standard diagnostic tool for OSA, is often unavailable due to patient financial and geographic constraints. Our objective is to analyze the relationship between a patient's subjective complaints and the results from their PSG to determine the diagnostic value of the Pediatric Sleep Questionnaire (PSQ) for detecting OSA in children.

METHODS

A retrospective chart review was conducted for pediatric patients with suspected OSA from March 2012 to January 2014. Preoperative PSQ scores were compared with the results from PSG in the form of Apnea-Hypopnea Index (AHI) and Respiratory Disturbance Index (RDI) values. AHI and RDI values ranging from 1 to 5 were classified as mild OSA while values ranging from 5 to 10 were classified as moderate OSA.

RESULTS

A total of 161 patients were recruited for this study with 63 patients (39%) both completing the PSQ and undergoing PSG. Sensitivity of the positive questionnaire was higher in patients with AHI and RDI values indicative of moderate OSA (95% and 100% respectively) versus values indicative of mild OSA (83% and 86% respectively). Conversely, the positive predictive value of the positive questionnaire (n=49) was lower in patients with AHI and RDI values indicative of moderate OSA (39% and 46% respectively) versus values indicative of mild OSA (70% and 80% respectively).

CONCLUSION

The PSQ has high diagnostic value for screening patients with suspected OSA. We recommend the use of the PSQ in the primary care setting for children with suspected OSA.

Differences in Anthropometric and Clinical Features among Preschoolers, School-Age Children, and Adolescents with Obstructive Sleep Apnea-A Hospital-Based Study in Taiwan

Pediatric obstructive sleep apnea (OSA) is associated with adverse health outcomes; however, little is known about the diversity of this population. This retrospective study aims to investigate age-related differences in the anthropometric and clinical features of this population. A total of 253 Taiwanese children (70 (27.7%) girls and 183 (72.3%) boys) with OSA were reviewed. Their median age, body mass index (BMI) z-score, and apnea-hypopnea index were 6.9 years, 0.87, and 9.5 events/h, respectively. The cohort was divided into three subgroups: ‘preschoolers’ (≥2 and <6 years), ‘school-age children’ (≥6 and <10 years), and ‘adolescents (≥10 and <18 years)’. The percentage of the male sex, BMI z-score, neck circumference, systolic blood pressure z-score, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio tended to increase with age. Adenoid grades tended to decrease with age. Overall, disease severity was independently correlated with neck circumference, tonsil size, and adenoid grade. Increased neck circumference and tonsillar hypertrophy were the most influential factors for younger children, whereas adenoidal hypertrophy became more important at an older age. In conclusion, gender prevalence ratio, anthropometric measures, and clinical features varied with age, and the pathogenic drivers were not necessarily the same as the aggravating ones.

Relationships Among and Predictive Values of Obesity, Inflammation Markers, and Disease Severity in Pediatric Patients with Obstructive Sleep Apnea Before and After Adenotonsillectomy

Both obstructive sleep apnea (OSA) and obesity are major health issues that contribute to increased systemic inflammation in children. To date, adenotonsillectomy (AT) is still the first-line treatment for childhood OSA. However, the relationships among and predictive values of obesity, inflammation, and OSA severity have not been comprehensively investigated. This prospective study investigated body mass index (BMI), serum inflammatory markers, and OSA severity before and after AT in 60 pediatric patients with OSA. At baseline, differences in levels of interleukin-6, interleukin-9, basic fibroblast growth factor, platelet-derived growth factor-BB, as well as regulated on activation, normal T cell expressed and secreted (RANTES) were significant among the various weight status and OSA severity subgroups. After 3 months postoperatively, the differences in these inflammatory markers diminished along with a decrease in OSA severity while obesity persisted. The rate of surgical cure (defined as postoperative obstructive apnea-hypopnea index < 2.0 and obstructive apnea index < 1.0) was 62%. Multivariate analysis revealed that age, BMI z-score, granulocyte-macrophage colony-stimulating factor, monocyte chemotactic protein-1, and RANTES independently predicted surgical cure. Despite the significant reductions in inflammatory markers and OSA severity after AT, an inter-dependent relationship between obesity and OSA persisted. In addition to age and BMI, several inflammatory markers helped to precisely predict surgical cure.

Therapeutic effects and modulatory mechanism of Alpiniae oxyphyllae Fructus in chronic intermittent hypoxia induced enuresis in rats

OBJECTIVE

The objective of this study was to explore the effect of Alpiniae oxyphyllae Fructus (AOF) on a rat model of chronic intermittent hypoxia (CIH)-induced enuresis. Findings of this study may help identify therapeutic targets in children with nocturnal enuresis (NE).

METHODS

Female rats were randomly divided into a control group (saline gavage, 4 weeks of normal air), CIH group (saline gavage, 4 weeks of CIH), and AOF group (AOF gavage, 4 weeks of CIH). The variables measured in this study included water intake, urine output, bladder leak point pressure (BLPP), malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activity. The expression levels of the purinergic P₂X₃ receptor, muscarinic M₃ receptor, and ß₃-adrenergic receptor (ß₃-AR) in the bladder were also measured. The bladder was subjected to haematoxylin and eosin (HE) and Weigert staining, and histological changes were observed under a light microscope to evaluate the morphological changes in the bladder in each group.

RESULTS

Compared with the control group, urine output was increased, and the BLPP was decreased in the CIH group, but AOF administration decreased urine output and increased BLPP. In addition, the serum MDA level increased and the SOD activity decreased in the CIH group compared with the control group. Administration of AOF decreased the MDA level and increased the SOD activity. Additionally, compared with the control group, HE and Weigert staining in the CIH group showed that the bladder detrusor muscle bundles were disordered and loose, some muscle bundles were broken, the content of collagen fibres in the gap was reduced, and the gap was significantly widened. However, following the administration of AOF, the bladder detrusor muscle bundles were neatly arranged, and the content of collagen fibres in the gap was increased. Furthermore, compared with the control group, the purinergic P₂X₃ receptor and muscarinic M₃ receptor were expressed at higher levels, and ß₃-AR was expressed at lower levels in the CIH group, but AOF administration decreased the expression of the purinergic P₂X₃ receptor and muscarinic M₃ receptor and increased the expression of the ß₃-AR.

CONCLUSIONS

AOF improves enuresis by inhibiting oxidative stress and regulating the expression of the purinergic P₂X₃ receptor, muscarinic M₃ receptor, and ß₃ adrenergic receptor.

Popularity of sleep disordered breathing in childhood: an analysis of worldwide search using Google Trends

BACKGROUND

Sleep-disordered breathing (SDB) is a general term encompassing a variety of breathing problems occurring during the sleep and characterized by frequently reported signs such as sleep apneas and snoring. Published studies on this topic are increasing over time, as demonstrated by the number of papers available on on-line databases.

METHODS

Google Trends is a freely accessible and reliable online portal, which allows to explore internet search data. Due to the focus on of childhood SDB in published research, and because of its impact on health and wellbeing, this original study aims at investigating the worldwide popularity of most common sleep signs (apnea and snoring) from January 1st, 2004 to present time.

RESULTS

The trend of interest for 'sleep', 'sleep apneas' and 'snoring' limited to pediatric age was lower than its overall popularity in the general population, thus reflecting a lower interest of these symptoms in children than in adults. Unlike an increasing trend of ongoing research, the popularity of pediatric sleep apnea and snoring was found to be relatively low around the world, and remained fairly stable over time.

CONCLUSIONS

This is a matter for concern, since the low popularity of SDB in children is counterbalanced by a need for reinforcing educational programs aimed at increasing widespread awareness, diagnosis and management of this condition.

Comparison of Positive Screening for Obstructive Sleep Apnea in Patients With and Without Cleft Lip and Palate

OBJECTIVE

To compare the prevalence of increased risk of obstructive sleep apnea (OSA) in children with and without cleft lip and/or palate using a previously validated questionnaire and to examine the clinical and demographic variables that may lead to increased OSA risk.

DESIGN

Prospective, cross-sectional study.

PARTICIPANTS

One hundred fifty-five cleft lip palate and 155 noncleft children between 2 and 18 years old.

INTERVENTIONS

The Pediatric Sleep Questionnaire (PSQ): Sleep Related Breathing Disorder Scale was used for screening of increased OSA risk. Age, body mass index (BMI), gender, breast-feeding, and bottle-feeding durations were recorded for all patients. Cleft type, lip and palate operation times, nasoalveolar molding, or nutrition plaque usage was documented for the cleft lip palate group. Pearson χ² or Fisher exact test was used for the evaluation of the qualitative variables and independent samples t test or Mann Whitney U test for quantitative variables. P < .05 was accepted as statistically significant.

RESULTS

The mean ages were 7.52 ± 3.91 and 7.50 ± 3.89 years for cleft lip palate and control groups, respectively. No significant differences were observed between the groups for age, gender, or BMI. Breast-feeding duration was significantly higher, and bottle-feeding duration was lower in the control group (P < .05). Mean PSQ score was significantly higher in cleft lip palate group (0.18 ± 0.12) than in control group (0.13 ± 0.1, P < .001); and prevalence of increased OSA risk was significantly higher in patients with both cleft lip and palate (P = .020).

CONCLUSIONS

Positive OSA screening ratio of children with cleft lip and palate (12.2%) was significantly higher than the controls (4.5%).

Risk Factors for Obstructive Sleep Apnea Syndrome in Children: State of the Art

The obstructive sleep apnea syndrome (OSAS) represents only part of a large group of pathologies of variable entity called respiratory sleep disorders (RSD) which include simple snoring and increased upper airway resistance syndrome (UARS). Although the etiopathogenesis of adult OSAS is well known, many aspects of this syndrome in children are still debated. Its prevalence is about 2% in children from 2 to 8 years of age, mostly related to the size of the upper airways adenoid tissue. Several risk factors linked to the development of OSAS are typical of the pediatric age. The object of this paper is to analyze the state of the art on this specific topic, discussing its implications in terms of diagnosis and management.

Caregiver support and positive airway pressure therapy adherence among adolescents with obstructive sleep apnea

Introduction

Positive airway therapy (PAP) adherence rates are suboptimal among adolescents with obstructive sleep apnea (OSA) and strategies to increase PAP adherence is a clinical priority. This study evaluates if caregiver support is associated with PAP adherence rates among adolescents with OSA.

Methods

We conducted a retrospective study and evaluated PAP adherence rates among adolescents with OSA from 2012 to 2017. Adherence was measured as continuous variables: average PAP usage (minutes per night) and average PAP usage >4 hours/night (% of all nights). We evaluated if adolescents with OSA who were receiving practical caregiver support with PAP had higher adherence than adolescents with OSA without caregiver support.

Results

One hundred and seven adolescents with OSA (mean age=14.1±2.5 years, 64.5% male, mean BMI percentile=89.0±21.8) seen between January 2012 and August 2017 at our institution were included. In this study, 60.7% (n=65) of adolescents with OSA were receiving practical caregiver support with PAP therapy. Adolescents with OSA receiving practical caregiver support with PAP used therapy for a significantly greater duration each night compared to adolescents who were not receiving practical caregiver support (298.5±206.7 versus 211.9±187.2 minutes; P=0.02). Greater time since the initial PAP prescription was independently associated with PAP adherence.

Conclusion

Focusing on PAP adherence early may help adolescents with OSA incorporate therapy into their nightly routine, which may improve adherence and lead to improved health outcomes in adolescents with OSA. Practical caregiver support may be an essential component of ensuring optimal PAP adherence among adolescents with OSA.

Impact of weight-loss management on children and adolescents with obesity and obstructive sleep apnea

OBJECTIVES

To evaluate the impact of weight-loss management on obstructive sleep apnea (OSA) in children and adolescents with obesity. We hypothesized that a reduction in the degree of obesity was associated with a reduction in the apnea-hypopnea index (AHI).

METHODS

OSA (AHI ≥2) was investigated using a type 3 portable sleep device (Nox T3) in children and adolescents aged 7-18 years with overweight or obesity (body mass index standard deviation score (BMI SDS) > 1.28) at enrollment in a chronic care multidisciplinary overweight- and obesity treatment clinic. Individuals with OSA were included prospectively and longitudinally. A follow-up sleep examination was performed after 6 and 12 months from baseline accompanied by anthropometric measurements.

RESULTS

At baseline, 62 children with OSA were included (median age = 13.4 years, median BMI SDS = 3.16). A total of 55 out of 62 children (89%) attended the first follow-up, and 29 out of 34 children (85%) with residual OSA attended the second follow-up. By the end of the study, the AHI was normalized in 27 out of 62 children (44%). In a multiple linear regression analysis, the decrease in BMI SDS was associated with the decrease in AHI upon the first follow-up (p = 0.02) independently of sex; age; baseline puberty stage; baseline tonsillar hypertrophy; baseline AHI; baseline BMI SDS; and time to follow-up. There was no association between change in BMI SDS and change in AHI from the first to the second follow-up (p = 0.81).

CONCLUSIONS

OSA improved during obesity treatment, and the reduction in BMI SDS was significantly associated with the reduction in AHI after approximately six months of treatment. This indicates that obesity treatment should be considered among the first-line treatments of OSA in children and adolescents affected by overweight or obesity.

Current perspectives on the correlation of nocturnal enuresis with obstructive sleep apnea in children

BACKGROUND

Obstructive sleep apnea (OSA) and nocturnal enuresis (NE) are common clinical problems in children. OSA and NE are thought to be interrelated, but the exact pathophysiological mechanisms are not yet clear. This review aims to explain the possible pathogenesis of NE in children with OSA.

DATE SOURCES

We have retrieved all relevant original articles from Database that have been published so far, including the prevalence studies of NE and OSA in children, sleep characteristic studies that use polysomnography (PSG) to focus on children with NE, and studies on the relationship between OSA and NE.

RESULTS

Clinical studies have revealed that the risk of NE in children with OSA was increased compared with that of their healthy peers. This increased risk may be associated with sleep disorders, bladder instability, detrusor overactivity, nocturnal polyuria, endocrine and metabolic disorders, and inflammation.

CONCLUSIONS

Cardiopulmonary and renal reflex-induced neuroendocrine disorder may play an important role in the mechanism of NE in children with OSA, but this remains to be confirmed by animal studies. Other causes such as oxidative stress and inflammatory responses need to be further researched.

Obstructive sleep apnea in children and adolescents with and without obesity

PURPOSE

To investigate the prevalence of obstructive sleep apnea (OSA) in children referred for obesity treatment, and to compare the prevalence with that of a normal-weight group. Moreover, we examined the association between Body Mass Index Standard Deviation Score (BMI SDS) and the Apnea-Hypopnea Index (AHI).

METHODS

This cross-sectional study included 139 children aged 7-18 years with overweight/obesity (BMI SDS >1.28) recruited from an obesity treatment clinic. The normal-weight group consisted of 33 children (BMI SDS ≤ 1.28) aged 7-18 years recruited from schools. Sleep examinations were performed using a type 3 portable sleep monitor (Nox T3). OSA was defined as AHI ≥ 2. Height and weight were measured and the tonsillar size was clinically estimated using the Brodsky scale.

RESULTS

The OSA prevalence was 44.6% in children with overweight/obesity compared with 9.1% in the normal-weight group (p = 0.0002), and the relative risk of OSA was 4.9 (95% CI 1.6-14.7). In a logistic regression, a one-unit increase in the BMI SDS increased the odds of having OSA by a factor of 1.92 independent of age, sex, tonsillar hypertrophy, and asthma (95% CI 1.33-2.76, p = 0.0005). A generalized linear regression adjusted for the same variables revealed an association between BMI SDS and AHI (a one-unit increase in the BMI SDS equaled an average increase in the AHI of 35% (95% CI 19-53%, p < 0.0001)).

CONCLUSIONS

In this study, children with overweight/obesity had a significantly higher prevalence of OSA compared with a normal-weight group. Increased BMI SDS was associated with increased AHI.

Utility of Neck, Height, and Tonsillar Size to Screen for Obstructive Sleep Apnea among Obese Youth

Objectives

To determine whether neck:height ratio combined with adenoid and tonsillar size is a good predictive tool for obstructive sleep apnea in obese youth.

Study Design

Cross-sectional study.

Setting

Sleep clinics at the Hospital for Sick Children, Toronto, Canada.

Subjects and Methods

Consented obese individuals aged 8 to 18 years were recruited between 2013 and 2015. Anthropometric measures were obtained by a trained research coordinator in a standardized manner. Otolaryngologists evaluated adenoid and tonsil sizes. Obstructive sleep apnea was diagnosed with an overnight polysomnogram as an obstructive apnea-hypopnea index ≥2. Multivariable logistic regressions investigated the relationship between potential predictors and obstructive sleep apnea. The C-statistic measured the predictive ability.

Results

Of the 53 subjects (median age, 13 years; 55% males), 28 (53%) were diagnosed with obstructive sleep apnea, with a median index of 10.6 per hour. In a logistic regression controlling for adenoid size, enlarged tonsils were significantly associated with the presence of obstructive sleep apnea ( P < .01). Adding neck:height ratio into the model improved the model predictive ability (C-index increased from 0.73 to 0.84). Controlling for tonsil and adenoid sizes, an increase in neck:height ratio was significantly associated with the presence of obstructive sleep apnea ( P = .01).

Conclusion

Our study suggests that neck:height ratio combined with tonsillar hypertrophy may have a strong predictive ability for obstructive sleep apnea and may be useful in an ambulatory setting to screen obese youth at high risk. These findings should be confirmed in a larger study.

Association among obesity, overweight and autism spectrum disorder: a systematic review and meta-analysis

Obesity, overweight and autism spectrum disorder (ASD) remain serious public health problems. Although lots of studies have recently explored the association among obesity, overweight and ASD, the findings are inconsistent. Thus, we conducted a meta-analysis of epidemiological studies to examine the association among obesity, overweight and ASD. PubMed, Embase, and the Cochrane Library were used for literature searches to identify eligible studies published in English before November 15, 2016. Relevant studies estimating the association among obesity, overweight and ASD were included. Fifteen studies encompassing 49,937,078 participants and 1,045,538 individuals with ASD were included in this study. A random effects model was chosen to synthesize the effect sizes of individual studies. The prevalence of obesity was significantly higher in individuals with ASD than in controls (OR = 1.84, 95% confidence interval [CI]: 1.37–2.48, P < 0.001). However, the prevalence of overweight in individuals with ASD was not significantly different from that in controls (OR = 1.07, 95% CI: 0.83–1.38, P = 0.62). Both sensitivity analysis and publication bias testing revealed that the findings were robust. The meta-analysis showed a significant association between obesity and ASD. However, no significant association was identified between overweight and ASD.

2016 European Society of Hypertension guidelines for the management of high blood pressure in children and adolescents

Increasing prevalence of hypertension (HTN) in children and adolescents has become a significant public health issue driving a considerable amount of research. Aspects discussed in this document include advances in the definition of HTN in 16 year or older, clinical significance of isolated systolic HTN in youth, the importance of out of office and central blood pressure measurement, new risk factors for HTN, methods to assess vascular phenotypes, clustering of cardiovascular risk factors and treatment strategies among others. The recommendations of the present document synthesize a considerable amount of scientific data and clinical experience and represent the best clinical wisdom upon which physicians, nurses and families should base their decisions. In addition, as they call attention to the burden of HTN in children and adolescents, and its contribution to the current epidemic of cardiovascular disease, these guidelines should encourage public policy makers to develop a global effort to improve identification and treatment of high blood pressure among children and adolescents.

Formula for the prediction of apnea / hypopnea index in children with obstructive sleep apnea without polysomnography according to the clinical parameters: Is it reliable?

PURPOSE OF THE STUDY

The aim of the study was to propose "the risk formula" for obstructive sleep apnea in children according to the general and local clinical parameters and findings relevant for obstructive sleep apnea (OSA) severity. The unmet need for this formula arises from the economic burden of polysomnography (device, staff, training, special sleep centers, etc) as the golden standard for the diagnostics.

MATERIALS AND METHODS USED

The study was performed from January 2013 until January 2016 in the Sleep Center, Department for Neuroscience, School of Medicine of the University of Split, Department of Pediatrics, University Hospital Split, Croatia and ENT Dept. University Hospital in Split, Croatia. Inclusion criteria were: age > two years, AHI >1 diagnosed by polysomnography. Exclusion criteria were: chronic lung disease, active tonsillitis/pharyngitis at the time of the physical exam and syndromes that affect breathing. All polysomnograms were scored by a qualified sleep technologist and interpreted by two board certified sleep physicians independently. Age, sex, BMI, Mallampati score, tonsillar size and adenoids size were recorded. All statistical calculations were performed using SPSS 20.

RESULTS

In total 60 children were included in the study. The median of age was 5 years (range 2-9). There were 19 (32%) girls and 41 (68%) boys. Of all evaluated predictors, there were statistically significant differences in the values of AHI among children with different modified Mallampati score (χ2 = 28.2; p < 0.001), different size of tonsils (χ2 = 25.3; p < 0.001) and different size of adenoids (z = 2.7; p = 0,006) in univariate regression analysis. Strong positive association of AHI with modified Mallampati score (standardized B = 0.51; partial correlation = 0.542, r = 0.631) was found, as well as positive correlation of AHI with tonsillar size (standardized B = 0.246; partial correlation = 0.295,R = 0.489) in the multivariate forward stepwise regression analysis.

CONCLUSION

Even though we are aware that PSG is the gold standard for diagnostics of SDB there is a significant financial burden for this diagnostic procedure. That is why there is a necessity for establishing good clinical standards and possible formula for OSA severity evaluation. We propose formula which includes Mallampati score and tonsillar size for OSA -risk calculation in order to perform early therapeutic intervention thereby reducing the risk of long-term negative consequences. We recommend this formula as the screening formula in circumstances where PSG is not available, in cases when the "waiting list" is too long or when a child can not cooperate to perform it. In developing countries like Croatia on time intervention with reduced procedure-associated costs is of the utmost importance.

Association of T lymphocyte immune imbalance and IL-10 gene polymorphism with the risk of obstructive sleep apnea in children with obesity

PURPOSE

The purpose of this study is to determine the role of T lymphocyte immune imbalance and interleukin (IL)-10 gene polymorphism in the development of obstructive sleep apnea (OSA) in obese children.

METHODS

One hundred obese children at high-risk and low-risk for OSA based upon a sleep questionnaire were selected. Peripheral blood T lymphocyte subsets were measured by flow cytometry, and plasma IFN-γ, IL-4, and IL-10 cytokines were detected by ELISA. The relationships between OSA and the above variables were analyzed. IL-10 gene polymorphisms were analyzed by DNA sequencing.

RESULTS

Ninety subjects completed all the tests. Forty-two patients were diagnosed as OSA by PSG. Compared with non-OSA children, the levels of CD4⁺ T cells, IFN-γ, and IL-4 were increased (P < 0.05) whereas the numbers of CD4⁺ CD25⁺ Treg and NKT cells and the levels of IL-10 were reduced (P < 0.05). Multiple linear regression analysis showed that IL-10 level was negatively associated with OAHI (OR 0.352, 95% CI 0.286-0.540; P < 0.05). In multivariate analysis, IL-10 also had a strong negative association with OSA after adjustment for confounding factors from models 1 to 3. Correlative analysis showed that IL-10 levels had a positive association with CD4⁺ CD25⁺ Treg (r = 0.628, P < 0.01). Furthermore, the IL-10/A-1082G gene polymorphism correlated with OSA.

CONCLUSIONS

T lymphocyte immune imbalance was associated with OSA and IL-10 may play an important protective role in the pathogenesis of OSA in obese children.

Associations of Overweight, Obesity and Related Factors with Sleep-Related Breathing Disorders and Snoring in Adolescents: A Cross-Sectional Survey

Background: Sleep-related breathing disorders (SRBD) have been identified as a major public health problem closely related to adolescent obesity. We aimed to estimate the prevalences of SRBD and snoring in adolescents in Changchun City, Northeastern China, and to evaluate the associated factors in this population. Methods: In total, 1955 adolescents aged 11–18 years were recruited in Changchun City using stratified cluster sampling. Parents and caretakers of children completed the questionnaires, which included demographic characteristics, anthropometric parameters and a pediatric sleep questionnaire (SRBD scale). Logistic regression was used to analyze the relationship between SRBD, snoring and other factors. Results: The prevalences of SRBD and snoring in our population were 3.7% and 3.3%, respectively, and the prevalences of overweight and obesity were 12.6% and 4.9%. Multivariate logistic regression showed that urban residence (OR = 2.356, 95%CI: 1.251–4.435) and post-term birth (OR = 3.275, 95%CI: 1.396–7.683) were significantly associated with SRBD. Preterm birth (OR = 2.255, 95%CI: 1.021–4.980) and parental education level of university and above (OR = 0.265, 95%CI: 0.083–0.850) were significantly associated with snoring. Overweight (OR = 2.063, 95%CI: 1.062–4.006) was also related to snoring. Conclusions: The prevalences of SRBD and snoring were similar to those reported in previous studies. Urban residence and post-term birth were important influencing factors for SRBD; overweight, highest parental education level (university and above) and preterm birth were key factors affecting snoring in adolescents.

Pediatric Pulmonology year in review 2015: Part 2

Pediatric Pulmonology covers a broad range of research and scholarly topics related to children's respiratory disorders. For updated perspectives on the rapidly expanding knowledge in our field, we will summarize the past year's publications in our major topic areas, as well as selected publications in these areas from the core clinical journal literature outside our own pages. The current review (Part 2) covers articles on sleep-disordered breathing. Pediatr Pulmonol. 2016;51:740-746. © 2016 Wiley Periodicals, Inc.