The obesity phenotype in children with asthma

The association of co-morbid asthma and overweight/obese status with healthcare utilization and caregiver perception of health in children 4-17 years, a NHANES study

OBJECTIVE

Asthma and obesity are two of the most common chronic childhood illnesses. The purpose of this study was to better understand the relationship between co-morbid asthma and obesity in children aged 4-17 and whether it impacts the caregiver's perception of health and/or healthcare utilization.

METHODS

This was a secondary analysis of the National Health and Nutrition Examination Surveys (NHANES) datasets from 2007 to 2018. Cumulative logistic regression models were used to analyze the caregiver's perception of health, received healthcare, and overnight hospital stay as dependent variables. Asthma and weight status were included as covariates, with adjustment for age, income, head of the household's education, gender, race, and insurance.

RESULTS

The sample included 15,386 children. When looking at weight status in addition to asthma, compared to caregivers of children with current asthma and normal weight, caregivers of children with current asthma and with obesity are more likely to perceive their children as having worse health (OR = 1.73, 95%CI = [1.30, 2.32], p = 0.0003), and are more likely to have more frequent healthcare utilization but the results did not reach a statistical significance.

CONCLUSIONS

Caregiver's perception of overall health was worse in caregivers of those with co-morbid obesity/asthma than in caregivers of children with asthma alone. This indicates that caregivers of children with co-morbid asthma and obesity have insight into their children's condition and may be primed for discussion and counseling in the healthcare setting.

Effects of Obesity on Airway and Systemic Inflammation in Asthmatic Children

BACKGROUND

Obese asthma is a complex syndrome with certain phenotypes that differ in children and adults. There is no clear evidence regarding the presence of additive or synergistic pathological interaction between obesity and asthma in children.

OBJECTIVES

Our aim was to demonstrate the interaction of obesity and asthma in children in terms of airway and systemic inflammation by a controlled observational study.

METHODS

Four groups were formed: asthma obese (AO), asthma nonobese (ANO), non-AO (NAO), nonasthma nonobese (NANO). Spirometry test, fractional exhaled nitric oxide (FeNO) test, skin prick test, serum inflammatory biomarkers (C-reactive protein, C3, C4, adiponectin, leptin, resistin, periostin, YKL-40, Type 1, and Type 2 cytokines) were conducted and evaluated in all participants. Sputum inflammatory cells (sputum eosinophils and neutrophils) were evaluated in patients who could produce induced sputum and obesity-asthma interactions were determined.

RESULTS

A total of 153 participants aged 6-18 years were included in the study, including the AO group (n = 46), the ANO group (n = 45), the NAO group (n = 30), and the NANO group (n = 32). IL-4 (p < 0.001), IL-5 (p < 0.001), IL-13 (p < 0.001), resistin (p < 0.001), and YKL-40 (p < 0.001) levels were higher in patients with asthma independent of obesity. The lowest adiponectin level was found in the AO group and obesity-asthma interaction was detected (p < 0.001). Sputum eosinophilia (p < 0.01), sputum neutrophilia (p < 0.01), and FeNO levels (p = 0.07) were higher in asthmatic patients independent of obesity. In the group with paucigranulocytic inflammation, resistin and YKL-40 levels were significantly lower than in the group without paucigranulocytic inflammation (p < 0.01).

CONCLUSION

No interaction was found between obesity and asthma in terms of airway inflammation. Interaction between obesity and asthma was shown in terms of adiponectin level and resistin/adiponectin and leptin/adiponectin ratios. It was found that serum YKL-40 and resistin levels could be associated with airway inflammation.

Obesity-related asthma in children is characterized by T-helper 1 rather than T-helper 2 immune response: A meta-analysis

BACKGROUND

Asthma is a chronic inflammatory condition characterized by T-helper (T_H) 2 polarization. In children, the prevalence of obesity is associated with an increased incidence of asthma. Notably, obesity is linked with T_H1-mediated inflammation and has been identified as a major risk factor for asthma.

OBJECTIVE

To investigate the impact of obesity on T_H1 (tumor necrosis factor α, interferon gamma, interleukin (IL)-6, IL-8) and T_H2 (IL-4, IL-5, IL-10, IL-13) immune responses in children with asthma.

METHODS

We searched the MEDLINE and gray literature electronic databases for eligible studies from inception up until April 2020. The quality of included studies and evidence was independently assessed by 2 reviewers. The random-effects model was used in this meta-analysis, and outcomes were reported as standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

Overall, 5 studies comprising 482 participants met the inclusion criteria. The meta-analysis revealed an increased T_H2-mediated immune response in lean people with asthma compared with controls without asthma (SMD: -1.15 [95% CI: -1.93, 0.36]; I² = 93%; p^H < .001). However, in obese people with asthma, there was polarization toward T_H1 immune response compared with lean people with asthma (SMD: -0.43 [95% CI: -0.79, -0.08]; I² = 88%, p^H < .001).

CONCLUSION

This meta-analysis reveals that there are differences in immune responses mediated by T-helper cells in lean and obese children with asthma. Moreover, and not unique to asthma, obesity polarizes the immune response toward T_H1 rather than the classical T_H2. This could be an important aspect to understand to establish effective therapeutic targets for obese children with asthma.

Exercise and lifestyle changes in pediatric asthma

PURPOSE OF REVIEW

The purpose of this review is to discuss the most recent studies on lifestyle interventions in pediatric asthma. We include studies on physical activity and exercise, sedentary time, nutrition, behavioral therapy and the role of schools.

RECENT FINDINGS

Several small studies in children with asthma suggest that exercise interventions can improve aerobic fitness, asthma symptoms or control and quality of life. Existing evidence supports recommending higher intake of fruits and vegetables for asthma risk and control. In contrast, the 'Western diet' - high in refined grains, highly processed foods, red meats and fried foods with low intake of fruits and vegetables - has a proinflammatory effect and may alter microbiota composition leading to worse asthma outcomes. Finally, there are opportunities to utilize schools to promote physical activity, though standardization of asthma management in the schools is needed.

SUMMARY

Assessing physical activity/fitness levels, sedentary time and nutritional status is important in the management of children with asthma, as they are modifiable factors. Larger rigorous studies evaluating lifestyle interventions are needed to better inform current asthma guidelines as well as to understand the underlying mechanism(s) related to physical activity and diet in asthma.

Influence of weight status in the response to Step-2 maintenance therapies in children with asthma

Introduction

Overweight children with asthma may display impaired response to inhaled corticosteroids (ICS), possibly due to non-eosinophilic inflammation or weight-related lung compression; these mechanisms may differentially affect response to ICS and leukotriene receptor antagonists (LTRAs). We assessed whether weight status modified the response to low-dose ICS and LTRA Step-2 monotherapy.

Methods

A historical cohort study from clinical data linked to administrative databases was conducted among children aged 2–18 years with specialist-diagnosed asthma who were initiating or continuing a Step-2 monotherapy from 2000 to 2007 at the Montreal Children’s Hospital Asthma Centre. The outcome was time-to-management failure defined as any step-up in therapy, acute care visit, hospitalisation or oral corticosteroids for asthma, whichever occurred first. The independent and joint effects of weight status (body mass index [BMI] percentile) and time-varying treatment on time-to-management failure were estimated with marginal structural Cox models. The likelihood ratio test (LRT) and relative excess risk due to interaction (RERI) were computed to assess treatment effect modification by weight status on the multiplicative and additive scales.

Results

Of the 433 and 85 visits with a low-dose ICS and LTRA prescription, respectively, 388 management failures occurred over 14 529 visit-weeks of follow-up. Children using LTRA compared with low-dose ICS tended to have an overall higher risk of early management failure (HR 1.52; 95% CI 0.72 to 3.22). Irrespective of treatment, the hazard of management failure increased by 5% (HR 1.05; 95% CI 1.01 to 1.10) for every 10-unit increase in BMI percentile. An additional hazard reduction of 17% (HR 0.83; 95% CI 0.70 to 0.99) was observed for every 10-unit increase in BMI percentile among LTRA users, but not for ICS (HR 0.95; 95% CI 0.86 to 1.04). The LRT indicated a departure from exact multiplicativity (p<0.0001), and the RERIs for ICS and LTRA were −0.05 (95% CI −0.14 to 0.05) and −0.52 (95% CI −1.76 to 0.71).

Conclusions

Weight status was associated with earlier time-to-management failure in children prescribed Step-2 therapy. This hypothesis-generating study suggests that LTRA response increases in children with higher BMI percentiles, although further research is warranted to confirm findings.

A novel nutritional intervention improves lung function in overweight/obese adolescents with poorly controlled asthma: the Supplemental Nutrition in Asthma Control (SNAC) pilot study

Asthma in the obese is often severe, difficult to treat, and characterized by less eosinophilic inflammation than asthma in the nonobese. Obesity-associated metabolic dysregulation may be a causal factor. We previously reported that a nutrient- and fiber-dense bar [Children's Hospital Oakland Research Institute (CHORI)-bar], which was designed to fill gaps in poor diets, improved metabolism in healthy overweight/obese (OW/OB) adults. In this pilot trial, OW/OB adolescents with poorly controlled asthma were randomized to weekly nutrition/exercise classes with or without twice-daily CHORI-bar consumption. Intent-to-treat analysis did not indicate CHORI-bar-specific effects. However, restricting the analysis to participants with acceptable compliance and a relatively low fraction of exhaled nitric oxide (FENO; <50/ ppb, a surrogate for noneosinophilic asthma; study participants: CHORI-bar, n = 16; controls, n = 15) indicated that CHORI-bar-specific, significant improvements in lung function (forced vital capacity, percent-predicted forced expiratory volume in 1 s, and percent-predicted forced expiratory flow between 25 and 75% of forced vital capacity), primarily in participants with low chronic inflammation (high-sensitivity C-reactive protein <1.5 mg/L). (We previously observed that chronic inflammation blunted CHORI-bar-induced metabolic improvements in healthy OW/OB adults.) Lung function improvement occurred without weight loss and was independent of improvements in metabolic and anthropometric end points and questionnaire-based measures of asthma control and quality of life. This study suggests that a nutritional intervention can improve lung function in OW/OB adolescents with asthma and relatively low FENO without requiring major changes in dietary habits, lifestyle, or weight loss and that this effect is blunted by chronic inflammation.-Bseikri, M., McCann, J. C., Lal, A., Fong, E., Graves, K., Goldrich, A., Block, D., Gildengoren, G. L., Mietus-Snyder, M., Shigenaga, M., Suh, J., Hardy, K., Ames, B. N. A novel nutritional intervention improves lung function in overweight/obese adolescents with poorly controlled asthma: the Supplemental Nutrition in Asthma Control (SNAC) pilot study.

Association of Childhood Obesity and the Immune System: A Systematic Review of Reviews

The growing prevalence of childhood obesity has become a serious health problem over the past decades. As the immune system is greatly affected by excess weight, in this review of reviews, we discuss the findings of review articles about the relationship between childhood/maternal obesity and children's immune system. We searched English-language articles in PubMed, Scopus, ISI Thomson Reuters, and Google Scholar databases. All relevant reviews, either systematic or narrative, were retrieved. Then their quality was assessed by using the Assessment of Multiple Systematic Reviews and International Narrative Systematic Assessment tools, respectively. In the final step, 26 reviews were included. Our review suggests that childhood obesity is associated with extensive changes in the serum levels of inflammatory and anti-inflammatory cytokines and proteins, as well as the number of immune cells and their behavior. Therefore, it might cause or exacerbate diseases such as asthma, allergy, atopic dermatitis (AD), and obstructive sleep apnea syndrome. Moreover, childhood obesity may reduce the immune system responsiveness to vaccines and microorganisms. Furthermore, studies suggest that maternal obesity increases the risk of asthma in offspring. Future studies are needed to determine different associations of childhood obesity with allergy, atophic dermatitis, and autoimmune diseases.

The Danish National Database for Asthma: establishing clinical quality indicators

Asthma is one of the most common chronic diseases worldwide affecting more than 300 million people. Symptoms are often non-specific and include coughing, wheezing, chest tightness, and shortness of breath. Asthma may be highly variable within the same individual over time. Although asthma results in death only in extreme cases, the disease is associated with significant morbidity, reduced quality of life, increased absenteeism, and large costs for society. Asthma can be diagnosed based on report of characteristic symptoms and/or the use of several different diagnostic tests. However, there is currently no gold standard for making a diagnosis, and some degree of misclassification and inter-observer variation can be expected. This may lead to local and regional differences in the treatment, monitoring, and follow-up of the patients. The Danish National Database for Asthma (DNDA) is slated to be established with the overall aim of collecting data on all patients treated for asthma in Denmark and systematically monitoring the treatment quality and disease management in both primary and secondary care facilities across the country. The DNDA links information from population-based disease registers in Denmark, including the National Patient Register, the National Prescription Registry, and the National Health Insurance Services register, and potentially includes all asthma patients in Denmark. The following quality indicators have been selected to monitor trends: first, conduction of annual asthma control visits, appropriate pharmacological treatment, measurement of lung function, and asthma challenge testing; second, tools used for diagnosis in new cases; and third, annual assessment of smoking status, height, and weight measurements, and the proportion of patients with acute hospital treatment. The DNDA will be launched in 2016 and will initially include patients treated in secondary care facilities in Denmark. In the nearby future, the database aims to include asthma diagnosis codes and clinical data registered by general practitioners and specialised practitioners as well.

Asthma, allergy, and obesity: Examining the relationship among Nevada children

OBJECTIVE

The majority of pediatric asthma is atopic, but whether pediatric obese asthma is atopic is indeterminate in the literature. In Nevada, children become sensitized to aeroallergens, a risk factor for asthma, at young ages. Additionally, Nevada children have high rates of obesity. Our objective is to determine whether elevated body mass index (BMI) is associated with asthma severity, allergen sensitization, and polysensitization.

METHODS

Medical records from a pediatric allergy clinic provided BMI percentile, physician-diagnosed asthma severity, skin prick test data, and sociodemographics such as age, race, sex, and insurance status from asthmatic patients. Descriptive statistics and binary and multinomial logistic regression were conducted.

RESULTS

In this population (N = 125) aged 1-16, 61% were male, 65% were white, and 74% had private health insurance. Sixty-five percent of children were under/healthy weight and 29% were overweight/obese. Asthma symptoms were moderate in 66% of the population, and severe in 18%. Nearly 85% of this population was atopic, and 82% were polysensitized. Sensitization and polysensitization occurred in all weight categories. Asthma severity and elevated BMI were not associated significantly. Overweight/obese children (≥85^th percentile) had lower odds of allergen sensitization (adjusted odds ratio 0.26, 95% CI = 0.85-0.78, p = 0.016) and polysensitization (adjusted odds ratio 0.30, 95% CI = 0.11-0.85, p = 0.023) than healthy weight children (<85^th percentile).

CONCLUSION

Although overweight children did show allergen sensitization, those who were overweight had lower odds of allergen sensitization and lower odds of polysensitization, as compared to normal weight asthmatic children. Elevated BMI was not a significant predictor of asthma severity.

Lack of Recognition, Diagnosis, and Treatment of Overweight/Obesity in Children Hospitalized for Asthma

OBJECTIVES

Information is lacking regarding recognition and treatment of overweight and obesity in children hospitalized for asthma. The study objectives were to determine the current practice of recognition, diagnosis, and treatment of overweight and obesity for children hospitalized for asthma and to describe demographic, asthma, and weight characteristics for these patients.

METHODS

A retrospective record review was conducted for children admitted to the hospital with asthma in 2012. Charts were reviewed for evidence of recognition, diagnosis, and treatment of overweight and obesity. Subjects were classified into age-adjusted Centers for Disease Control and Prevention weight categories based on BMI percentile and chronic asthma severity categories according to National Asthma Education and Prevention Program guidelines.

RESULTS

A total of 510 subjects aged 3 to 17 years were studied. Obesity was present in 19.6% and overweight in 13.3% of subjects. BMI percentile was recorded in only 3.3% of all charts, in only 11% of subjects with obesity, and in 0% of subjects with overweight. BMI percentile was documented more often in subjects with severe obesity (P = .013) and with moderate to severe persistent asthma (P = .035). Only 9 of 168 subjects who were overweight or obese (5.6%) were given a discharge diagnosis indicating overweight or obesity, and 14 (8.3%) received treatment. Chronic asthma severity differed by BMI weight category (P < .001), with a significant relationship between obesity status and chronic asthma severity in older subjects (P = .033). There were no differences in severity of acute episodes based on weight group.

CONCLUSIONS

Overweight and obesity were underrecognized, underdiagnosed, and undertreated in children hospitalized for asthma.

Associations between asthma, overweight and physical activity in children: a cross-sectional study

Background

Asthma and obesity are highly prevalent in children, and are interrelated resulting in a difficult-to-treat asthma-obesity phenotype. The exact underlying mechanisms of this phenotype remain unclear, but decreased physical activity (PA) could be an important lifestyle factor. We hypothesize that both asthma and overweight/obesity decrease PA levels and interact on PA levels in asthmatic children with overweight/obesity.

Methods

School-aged children (n = 122) were divided in 4 groups (healthy control, asthma, overweight/obesity and asthma, and overweight/obesity). Children were asked to perform lung function tests and wear an activity monitor for 7 days. PA was determined by: step count, active time, screen time, time spent in organized sports and active transport forms. We used multiple linear regression techniques to investigate whether asthma, body mass index-standard deviation score (BMI-SDS), or the interaction term asthma x BMI-SDS were associated with PA. Additionally, we tested if asthma features (including lung function and medication) were related to PA levels in asthmatic children.

Results

Asthma, BMI-SDS and the interaction between asthma x BMI-SDS were not related to any of the PA variables (p ≥ 0.05). None of the asthma features could predict PA levels (p ≥ 0.05). Less than 1 in 5 children reached the recommended daily step count guidelines of 12,000 steps/day.

Conclusion

We found no significant associations between asthma, overweight and PA levels in school-aged children in this study. However, as PA levels were worryingly low, effective PA promotion in school-aged children is necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3600-1) contains supplementary material, which is available to authorized users.

Association between obesity and asthma - epidemiology, pathophysiology and clinical profile

Obesity is a risk factor for asthma, and obese asthmatics have lower disease control and increased symptom severity. Several putative links have been proposed, including genetics, mechanical restriction of the chest and the intake of corticosteroids. The most consistent evidence, however, comes from studies of cytokines produced by the adipose tissue called adipokines. Adipokine imbalance is associated with both proinflammatory status and asthma. Although reverse causation has been proposed, it is now acknowledged that obesity precedes asthma symptoms. Nevertheless, prenatal origins of both conditions complicate the search for causality. There is a confirmed role of neuro-immune cross-talk mediating obesity-induced asthma, with leptin playing a key role in these processes. Obesity-induced asthma is now considered a distinct asthma phenotype. In fact, it is one of the most important determinants of asthma phenotypes. Two main subphenotypes have been distinguished. The first phenotype, which affects adult women, is characterised by later onset and is more likely to be non-atopic. The childhood obesity-induced asthma phenotype is characterised by primary and predominantly atopic asthma. In obesity-induced asthma, the immune responses are shifted towards T helper (Th) 1 polarisation rather than the typical atopic Th2 immunological profile. Moreover, obese asthmatics might respond differently to environmental triggers. The high cost of treatment of obesity-related asthma, and the burden it causes for the patients and their families call for urgent intervention. Phenotype-specific approaches seem to be crucial for the success of prevention and treatment.

A Multifactorial Weight Reduction Programme for Children with Overweight and Asthma: A Randomized Controlled Trial

Background

There is increasing evidence that obesity is related to asthma development and severity. However, it is largely unknown whether weight reduction can influence asthma management, especially in children.

Objective

To determine the effects of a multifactorial weight reduction intervention on asthma management in overweight/obese children with (a high risk of developing) asthma.

Methods

An 18-month weight-reduction randomized controlled trial was conducted in 87 children with overweight/obesity and asthma. Every six months, measurements of anthropometry, lung function, lifestyle parameters and inflammatory markers were assessed. Analyses were performed with linear mixed models for longitudinal analyses.

Results

After 18 months, the body mass index-standard deviation score decreased by -0.14±0.29 points (p<0.01) in the intervention group and -0.12±0.34 points (p<0.01) in the control group. This change over time did not differ between groups (p>0.05). Asthma features (including asthma control and asthma-related quality of life) and lung function indices (static and dynamic) improved significantly over time in both groups. The FVC% predicted improved over time by 10.1 ± 8.7% in the intervention group (p<0.001), which was significantly greater than the 6.1 ± 8.4% in the control group (p<0.05).

Conclusions & clinical relevance

Clinically relevant improvements in body weight, lung function and asthma features were found in both the intervention and control group, although some effects were more pronounced in the intervention group (FVC, asthma control, and quality of life). This implies that a weight reduction intervention could be clinically beneficial for children with asthma.

Trial Registration

ClinicalTrials.gov NCT00998413

Mediating pathways from central obesity to childhood asthma: a population-based longitudinal study

The mediating pathways linking obesity and asthma are largely unknown. We aimed to investigate the mediating pathways and to search for the most prominent pathological mechanism between central obesity and childhood asthma.In the Taiwan Children Health Study, we collected data on an open cohort of children aged 9-13 years. Children's respiratory outcomes, atopic conditions, obesity measures and pulmonary function were surveyed annually between 2010 and 2012. Exhaled nitric oxide fraction concentrations were recorded in 2012. Generalised estimating equations and general linear models were used to examine the associations between central obesity, possible mediators and asthma. Structural equation models were applied to investigate the pathways that mediate the link between central obesity and asthma.Central obesity (waist-to-hip ratio) most accurately predicted childhood asthma. In the active asthma model, the percentage of mediation was 28.6% for pulmonary function, 18.1% for atopy and 5.7% for airway inflammation. The percentage of mediation for pulmonary function was 40.2% in the lifetime wheeze model. Pulmonary function was responsible for the greatest percentage of mediation among the three mediators in both models.Decline in pulmonary function is the most important pathway in central obesity related asthma. Pulmonary function screening should be applied to obese children for asthma risk prediction.

Weight Management Interventions in Adult and Pediatric Asthma Populations: A Systematic Review

BACKGROUND

Ample evidence suggests a dose-response relationship between increasing weight and level of asthma risk or reduced asthma control. To establish reversibility, several randomized controlled trials (RCTs) have recently been published to investigate the impact of weight management on asthma. This systematic review synthesizes evidence from these RCTs on the effects of weight management (weight loss, weight maintenance, maintenance of lost weight, or weight gain prevention) interventions on asthma outcomes in both adult and pediatric populations.

METHODS

We searched Medline, CINAHL, PsychInfo, and Cochrane for studies published between 1950 and November 2014. Two researchers independently rated the included studies using the quality assessment tool for RCTs as outlined in the 2013 Obesity Treatment Guideline. Discrepancies were resolved by consensus after discussion between the raters and, if needed, with the senior author.

RESULTS

Four RCTs in adults and 3 in children and adolescents were included. The adult studies seem to consistently support the benefit of substantial weight loss, but a threshold effect may exist such that only weight loss beyond a minimal amount will likely lead to clinically important improvement in asthma outcomes. Three of them suggest that the threshold may lie between 5-10% of weight loss. RCTs in youth suggest that modest calorie reductions alone or combined with increased physical activity, or even a healthy normocaloric diet, may lead to improved asthma outcomes. However, most RCTs reviewed were limited by small sample size, short intervention durations, and short follow-up periods.

CONCLUSION

Trial evidence shows the promise of weight loss interventions for asthma control in adults and youth. More adequately-powered, long-term RCTs are needed to elucidate the role of weight loss and other weight management interventions in asthma control and prevention. Definitive data are needed to guide clinical and public health practice to effectively address the dual epidemic of obesity and asthma.

Pediatric obesity. An introduction

The prevalence of child and adolescent obesity in the United States increased dramatically between 1970 and 2000, and there are few indications that the rates of childhood obesity are decreasing. Obesity is associated with myriad medical, psychological, and neurocognitive abnormalities that impact children's health and quality of life. Genotypic variation is important in determining the susceptibility of individual children to undue gains in adiposity; however, the rapid increase in pediatric obesity prevalence suggests that changes to children's environments and/or to their learned behaviors may dramatically affect body weight regulation. This paper presents an overview of the epidemiology, consequences, and etiopathogenesis of pediatric obesity, serving as a general introduction to the subsequent papers in this Special Issue that address aspects of childhood obesity and cognition in detail.

Childhood obesity: immune response and nutritional approaches

Childhood obesity is characterized by a low-grade inflammation status depending on the multicellular release of cytokines, adipokines, and reactive oxygen species. In particular, the imbalance between anti-inflammatory T regulatory cells and inflammatory T helper 17 cells seems to sustain such a phlogistic condition. Alterations of gut microbiota since childhood also contribute to the maintenance of inflammation. Therefore, besides preventive measures and caloric restrictions, dietary intake of natural products endowed with anti-oxidant and anti-inflammatory activities may represent a valid interventional approach for preventing and/or attenuating the pathological consequences of obesity. In this regard, the use of prebiotics, probiotics, polyphenols, polyunsaturated fatty acids, vitamins, and melatonin in human clinical trials will be described.

Effects of dietary induced weight loss on exercise-induced bronchoconstriction in overweight and obese children

RATIONALE

Previous studies showed that obesity in asthmatic children is associated with more severe exercise-induced bronchoconstriction (EIB), compared with non-obese asthmatic children. This study investigates the effect of weight loss on EIB in overweight and obese asthmatic children.

METHODS

In this intervention study, children aged 8-18 years with EIB and moderate to severe overweight, followed a diet based on healthy daily intake for 6 weeks. Before and after the diet period they underwent an exercise challenge test in cold air. Primary outcome was change in exercise-induced fall in FEV1 and relation between weight loss and EIB. Secondary outcomes were changes in recovery of FEV1 ("area under the curve"; AUC), fraction of exhaled nitric oxide (FeNO) and scores of the Pediatric Asthma Quality of Life Questionnaire (PAQLQ) and Asthma Control Questionnaire (ACQ).

RESULTS

Twenty children completed the study. After the diet period, weight, and body mass index (BMI) were significantly reduced (changes respectively -2.6% and -1.5 kg/m(2), P < 0.01). There was a significant improvement of the percentage exercise-induced fall in FEV1 (30.6% vs. 21.8%, P < 0.01), AUC and PAQLQ score. The reduction in BMI z-score was significantly related to the reduction in the percentage exercise-induced fall in FEV1 in children that lost weight (r = 0.53, P = 0.03). There were no changes in FeNO and ACQ.

CONCLUSIONS

Dietary induced weight loss in overweight and obese asthmatic children leads to significant reduction in severity of EIB and improvement of the quality of life. The reduction in BMI z-score is significantly related to the improvement of EIB.

Pulmonary function in obese vs non-obese cats

Obesity is a risk factor in the development of several respiratory diseases. Lung volumes tend to be decreased, especially expiratory reserve volume, increasing expiratory flow limitation during tidal breathing. Barometric whole-body plethysmography is a non-invasive pulmonary function test that allows a dynamic study of breathing patterns. The objective of this study was to compare pulmonary function variables between obese and non-obese cats through the use of barometric whole-body plethysmography. Nine normal-weight and six obese cats were placed in the plethysmograph chamber, and different respiratory variables were measured. There was a significant decrease in tidal volume per kilogram ( P = 0.003), minute volume per kilogram ( P = 0.001) and peak inspiratory and expiratory flows per kilogram ( P = 0.001) in obese cats compared with non-obese cats. Obesity failed to demonstrate a significant increase in bronchoconstriction index variable enhanced pause (Penh), as previously reported in humans and dogs. The results show that feline obesity impairs pulmonary function in cats, although a significant increase in bronchoconstriction indexes was not observed. Non-invasive barometric whole-body plethysmography can help characterise mechanical dysfunction of the airways in obese cats.

Programming of the lung by early-life infection

Many important human diseases, such as asthma, have their developmental origins in early life. Respiratory infections in particular may alter the course of asthma and may either protect against or promote the development of this disease. It is likely that the nature of the effects depends on the type and age of infection and is determined by the impact of infection on the immune and respiratory systems. Immunity in early life is plastic and can be moulded by antigen encounter, which may enhance or reinforce the asthmatic phenotype of early life, or induce protective responses. Chlamydial respiratory infections have specific effects and may increase asthma severity in early life by promoting systemic interleukin 13 responses and causing permanent changes in lung structure. Respiratory viral infections, such as those of respiratory syncytial virus and rhinovirus, promote pro-asthmatic responses in early life that contribute to the induction of asthma. By contrast, probiotics or infection or exposure to certain bacteria, such as Streptococcus pneumoniae, may have protective effects in asthma by increasing the numbers and activity of regulatory T cells. Here, we review the impact of infections on the developmental origins of asthma. Understanding these effects may lead to new therapeutic approaches for asthma that either target deleterious infections or utilize beneficial ones.

Diet-induced weight loss in obese children with asthma: a randomized controlled trial

BACKGROUND

Obesity is highly prevalent in asthmatic children and associated with worse clinical outcomes. Energy restriction to induce weight loss in asthmatic children has not been investigated in a randomized controlled trial (RCT).

OBJECTIVE

To assess if (1) weight loss can be achieved in obese asthmatic children using a dietary intervention; and (2) changes in asthma outcomes occur following diet-induced weight loss.

METHODS

In a 10-week pilot RCT, obese asthmatic children, aged 8-17 years, were randomized to a wait-list control (WLC) (n = 15) or dietary-intervention group (DIG) (n = 13). Lung function, Asthma Control Questionnaire (ACQ) score, and sputum and systemic inflammation were assessed at baseline and post-intervention. (Australian New Zealand Clinical Trials Registry: ACTRN12610000955011).

RESULTS

Body mass index (BMI) z-score reduced significantly in the DIG vs. the WLC (-0.2 [-0.4, -0.1] vs. 0.0 [-0.1, 0.0], P = 0.014). Expiratory reserve volume (ERV) increased significantly within the DIG, but not compared to the WLC (0.7 [0.0, 1.0] L vs. 0.3 [0.0, 0.8] L, P = 0.355). ACQ improved significantly in the DIG, compared to the WLC (-0.4 [-0.7, 0.0] vs. 0.1 [0.0, 0.6], P = 0.004). Airway and systemic inflammation did not change within the DIG. In comparison, C-Reactive Protein (CRP) increased significantly in the WLC (-0.4 [-0.5, 0.4] vs. 0.7 [-0.1, 1.9], P = 0.037). Change (∆) in BMI z-score correlated with ∆CRP (r = 0.47, P = 0.012) and ∆exhaled nitric oxide (eNO) (r = 0.46, P = 0.034), and ∆ACQ was associated with ∆CRP (r = 0.43, P = 0.029).

CONCLUSION AND CLINICAL RELEVANCE

Dietary intervention can induce acute weight loss in obese asthmatic children with subsequent improvements in static lung function and asthma control. Systemic and airway inflammation did not change following weight loss. However, changes in BMI z-score were associated with changes in airway and systemic inflammation and this requires further investigation in a larger RCT. This is the first weight loss RCT conducted in obese asthmatic children. Diet-induced weight loss can achieve significant improvements in clinical outcomes for obese children with asthma.

Lean mass, not fat mass, is associated with lung function in male and female children with asthma

BACKGROUND

Whether body composition is associated with lung function in asthmatic children has not been investigated. This study aimed to primarily investigate whether BMI z-score and body composition were associated with respiratory function in asthmatic children.

METHODS

In a cross-sectional study, male (n = 27; mean age: 11.9 y (SD: 2.3)) and female (n = 21; mean age: 13.6 y (SD: 2.2)) asthmatic children underwent clinical assessment.

RESULTS

BMI z-score was associated with forced expiratory volume in 1 s (FEV1; r = 0.458), forced vital capacity (FVC; r = 0.477), and total lung capacity (TLC; r = 0.451) in males only (P < 0.05). Total lean mass was associated with FEV1 (r = 0.655), FVC (r = 0.562), and TLC (r = 0.635) in males, as was thoracic lean mass (FEV1 (r = 0.573), FVC (r = 0.526), and TLC (r = 0.497); P < 0.05). TLC was associated with total (r = 0.522) and thoracic (r = 0.532) lean mass in females (P < 0.05). Fat mass was not associated with lung function in this group.

CONCLUSION

Lean mass, not fat mass, is associated with lung function in children with asthma. The positive association between BMI z-score and respiratory function in male children is driven by lean mass. Although body weight can be easily monitored in the clinical setting, body composition can provide important information. Future research exploring lean mass and lung function associations could inform future interventions.

Sex differences in the relationship between asthma and overweight in Dutch children: a survey study

Objective

Obesity has been identified as a risk factor for asthma in children. However, in the Netherlands, the obesity prevalence is rising while the asthma prevalence in children is stabilising. The aim of this study is to clarify the association between asthma and Body Mass Index (BMI) in children and whether this association is influenced by sex.

Study Design

Parents of 39,316 children (6-16 years) in the south of the Netherlands were invited to complete an online questionnaire on respiratory symptoms, anthropometric variables and several potential confounding factors for asthma and obesity (including sex, birth weight and breastfeeding). Data was analysed by multivariable logistic regression models and an ordinal regression model.

Results

The response rate was 24% (n boys= 4,743, n girls= 4,529). The prevalence of asthma, overweight and obesity was 8%, 15% and 2% respectively. Body mass index - standard deviation Score (BMI-SDS) was related to current asthma (adjusted OR: 1.29; 95%CI: 1.14-1.45, p≤0.001). When stratified for sex, asthma and BMI-SDS were only related in girls (Girls: adjusted OR: 1.31; 95%CI: 1.13-1.51, p≤0.001. Boys: adjusted OR: 1.01; 95%CI: 0.91-1.14, p=0.72).

Conclusions

The positive association between BMI-SDS and asthma is only present in girls, not boys. Future studies into obesity and asthma should correct for sex in their analyses.

Immunometabolism in obese asthmatics: are we there yet?

Obesity is now recognised as a worldwide epidemic. The recent International Association for the Study of Obesity/International Obesity Taskforce (IASO/IOTF) analysis estimates that approximately 1.0 billion adults are currently overweight and a further 475 million are obese. Obesity has huge psychosocial impact with obese children and adolescents facing discrimination and stigmatization in many areas of their lives leading to body dissatisfaction, low self-esteem and depression. Indeed, obesity is recognised as an important risk factor for the development of several chronic diseases such as hypertension, cancer, asthma and metabolic syndrome. Chronic low grade systemic inflammation is considered as a hallmark of obesity and may possibly explain the link between obesity and chronic disease, in particular the increased incidence, prevalence and severity of asthma in obese individuals. There is now strong evidence for infiltration of immune and inflammatory cells into adipose tissue that drives systemic inflammation and subsequent end organ damage. In addition to adipocytes, the key adipose tissue resident immune cells are macrophages and mast cells. Immunometabolism, as an emerging field of investigation, explores the pivotal role of these immune cells in translating immunological changes to metabolic effects in obesity. Abundance of free fatty acids, along with other inflammatory cytokines shift the balance of metabolic homeostasis to pro-inflammatory status by influencing the development of inflammatory cell lineage, which, further exhibits distinct functional phenotypes. There is emerging evidence for macrophage activation and functional polarization of an anti-inflammatory M₂ phenotype towards a pro-inflammatory M₁ phenotype of macrophages in obese adipose tissue. Similarly, studies in both obese humans and murine models reveal the pathognomic presence of an increased number of mast cells in visceral adipose tissue. These suggest a possible contribution of mast cells to the unique metabolome of obese asthma. This review examines proposed multilevel interactions between metabolic and immune systems in obese asthmatics that underlie the negative effects of obesity and may offer significant therapeutic promise.

Obesity increases eosinophil activity in asthmatic children and adolescents

Background

A clear relationship between asthma and obesity has been reported, but the mechanisms remain unclear. The aim of this study was to evaluate the influence of obesity on eosinophil activity (chemotaxis and adhesion) in asthmatic children and adolescents compared with cells from healthy volunteers.

Methods

Asthmatic obese (AO), asthmatic non-obese (ANO), non-asthmatic obese (NAO) and non-asthmatic non-obese (NANO) individuals were included in the present study. The chemotaxis of eosinophils after stimulation with eotaxin (300 ng/ml), platelet-activating factor (10 μM; PAF) and RANTES (100 ng/ml) was performed using a microchemotaxis chamber. The eosinophil peroxidase activity was measured to determine the adhesion activity of eosinophils cultivated on fibronectin-coated plates. The serum leptin, adiponectin, TNF-α and IgE levels were quantified using ELISA assays.

Results

The serum IgE levels and eosinophil counts were significantly higher in asthmatic (obese and non-obese) individuals compared with non-asthmatic individuals (obese and non-obese). Spontaneous eosinophil chemotaxis was greater in the AO group compared with either the ANO or NANO groups. The activation of eosinophils using eotaxin and PAF increased eosinophil chemotaxis in the AO group. RANTES treatment increased eosinophil chemotaxis in the NAO group compared with the NANO or ANO groups. The activation of eosinophils using eotaxin significantly increased eosinophil adhesion in the AO group compared with other groups. The serum leptin and TNF-α levels were higher in obese subjects (asthmatic and non-asthmatic), whereas the levels of adiponectin did not significantly differ among these groups.

Conclusion

This study is the first to show increased eosinophilic activity (chemotaxis and adhesion) associated with high serum leptin and TNF-α levels in atopic asthmatic obese children and adolescents compared with non-obese healthy volunteers.

Multifactorial intervention for children with asthma and overweight (Mikado): study design of a randomised controlled trial

Background

In children, the prevalence’s of both obesity and asthma are disconcertingly high. Asthmatic children with obesity are characterised by less asthma control and a high need for asthma medication. As the obese asthmatic child is becoming more common in the clinical setting and the disease burden of the asthma-obesity phenotype is high, there is an increasing need for effective treatment in these children. In adults, weight reduction resulted in improved lung function, better asthma control and less need for asthma medication. In children this is hardly studied. The Mikado study aims to evaluate the effectiveness of a long term multifactorial weight reduction intervention, on asthma characteristics in children with asthma and a high body weight.

Methods/design

The Mikado study is a two-armed, randomised controlled trial. In total, 104 participants will be recruited via online questionnaires, pulmonary paediatricians, the youth department of the Municipal Health Services and cohorts of existing studies. All participants will be aged 6–16 years, will have current asthma, a Body Mass Index in the overweight or obesity range, and no serious comorbidities (such as diabetes, heart diseases). Participants in the intervention arm will receive a multifactorial intervention of 18 months consisting of sessions concerning sports, parental involvement, individual counselling and lifestyle advices including dietary advices and cognitive behavioural therapy. The control group will receive usual care. The primary outcome variables will include Forced Expiratory Volume in one second and Body Mass Index - Standard Deviation Score. Secondary outcomes will include other lung function parameters (including dynamic and static lung function parameters), asthma control, asthma-specific quality of life, use of asthma medication and markers of systemic inflammation and airway inflammation.

Discussion

In this randomised controlled trial we will study the potential of a multifactorial weight reduction intervention to improve asthma-related outcome measures in asthmatic children with overweight. Moreover, it will provide information about the underlying mechanisms in the relationship between asthma and a high body weight in children. These findings can contribute to optimal management programs and better clinical guidelines for children with asthma and overweight.

Trial registration

Clinicaltrial.gov NCT00998413

A systematic review of the association between obesity and asthma in children

AIM

To provide a comprehensive integration of contemporary studies focusing on the relationship between obesity and asthma in paediatric populations.

BACKGROUND

The simultaneous increase in asthma and obesity prevalence has been widely discussed over the past 20 years. Although studies have discovered a positive correlation between the two, evidence-based findings are needed to develop nursing interventions.

DESIGN

A quantitative systematic review on the literature was conducted from June-December 2011.

DATA SOURCES

An electronic database search was conducted for studies published between January 1966-May 2011. Additional articles were identified through the reference lists of reviewed papers.

REVIEW METHODS

Inclusion/exclusion criteria and quality appraisal were applied to ensure research primarily designed to study the relationship between obesity and asthma in children was included.

RESULTS

The majority of studies support a positive association between obesity and asthma in children. Among correlates recognized as important effect modifiers, gender was the most prominent, with obese girls more likely to have asthma diagnoses than obese boys. Scrutinization of covariates in selected studies revealed that most related to children's demographic characteristics and were inconsistent across the studies.

CONCLUSIONS

This review was designed to integrate contemporary scientific findings on the association between obesity and asthma by including a large number of studies with variant research designs. To identify high-risk groups and develop nursing interventions to help children affected by both epidemics, more interdisciplinary and well-designed investigations focusing on an expanded spectrum of correlates including demographic and behavioural factors are warranted.

Evaluation of adipokines: apelin, visfatin, and resistin in children with atopic dermatitis

Very little is known about the role of adipokines in atopic dermatitis (AD) in children. This study aimed at analyzing the serum levels of resistin, apelin, and visfatin in children with AD in relation to body weight, AD severity, and gender. Serum concentration of adipokines was measured in 27 children with AD and in 46 healthy subjects. Selected biochemical parameters were evaluated and skin prick test was performed. Serum levels of resistin and apelin were significantly higher, whereas serum visfatin concentration was significantly lower in children with AD versus healthy controls, although an increase in resistin levels was exclusively demonstrated in boys. In AD group, a significant increase in apelin levels in girls was documented. There was no relationship between adipokines levels and the degree of allergic sensitization. Receiver operating characteristic curve analysis demonstrated that the serum apelin cutoff value differentiating children with AD from those without was >137.8 pg/mL. Resistin and visfatin cutoff values were >3.8 ng/mL and ≤ 2.13 ng/mL, respectively. Apelin and visfatin can serve as excellent indicators to distinguish children with AD from those without disease.

Body size and lifestyle in an urban population entering adulthood: the 'Grow up Gothenburg' study

AIM

To present data on body size, lifestyle and health status in students in their final year in high schools in Gothenburg area, Sweden, with specific attention to origin and gender.

METHODS

Weight, height and waist circumference were measured by standardized procedures. Self-administered questionnaires described dietary habits, sleep, physical activity, body image, country of origin and general health.

RESULTS

Eighty-six percent of participants, (2600 girls, 2714 boys, mean age 18.6 years) were of Nordic origin, 86% reported no chronic health problems and 14%/19% of girls/boys were overweight or obese. Girls consumed more vegetables and fruits and fewer sweet drinks than boys, while breakfast consumption was most common in Nordic groups. Boys reported more positive answers than girls regarding body image. Nordic girls had more negative body image and higher morbidity compared with other groups.

CONCLUSION

Within this generally healthy cohort, boys were more likely to be overweight/obese than girls, although paradoxically boys were more satisfied with their appearance. Nordic girls constitute a group with particularly high risk of reporting low body self-esteem and chronic morbidity. In the longer term, the current cross-sectional data on body size, lifestyle and health will provide important baseline information for future follow-up studies of health outcomes in later life.

Obesity and childhood asthma - mechanisms and manifestations

PURPOSE OF REVIEW

Obesity is a chronic condition affecting children worldwide. However, the prevalence is higher in asthmatic children. Obese children most likely become obese adults. Understanding the clinical presentation of this subgroup is essential to their clinical management, now and in the future. This review highlights the most recent findings over the past 18 months in understanding the presentation and potential mechanisms of obesity in childhood asthma.

RECENT FINDINGS

Recent research suggests that inhaled corticosteroid efficacy is reduced in obese asthmatic children whereas ventilatory function and bronchoreactivity appear to be marginally affected. A paucity of studies describing airway inflammation and lung volume measurements in this subgroup limits their clinical characterization. Recent studies indicate metabolic abnormalities that typically manifest with excess adiposity may be associated with asthma, providing an interesting factor in the asthma-obesity link. The inception, persistence and composition of obesity prove important considerations for future studies.

SUMMARY

Highlighted is the need for more descriptive airway inflammation studies, lung volume assessments and longitudinal studies to better characterize the obese asthma phenotype in children and understand the pathogenesis from childhood to adulthood. Understanding the manifestations and mechanisms of obese asthma in childhood will help direct clinical management and targeted therapeutic interventions.