Association of body mass with pulmonary function in the Childhood Asthma Management Program (CAMP)

Relationship between FEV1/FVC and age in children with asthma

INTRODUCTION

Forced expiratory volume in the first second (FEV1)/forced vital capacity (FVC) normally decreases through childhood, increases briefly during early adolescence, and then declines throughout life. The physiology behind this temporary increase during early adolescence is not well understood. The objective of this study was to determine if this pattern occurs in children with asthma.

DESIGN

Single-center, cross-sectional, retrospective analysis of pulmonary function tests obtained over a 5-year period in children 5-18 years of age with persistent asthma.

RESULTS

A total of 1793 patients satisfied all inclusion and exclusion criteria. The mean age (±SD) was 10.4 ± 3.8 years. Forty-eight percent were female. Mean FEV1/FVC was 0.83 ± 0.09. FEV1/FVC was lower at 5 years of age than in healthy children, declined from age 5 to 11 by 5.7% compared to 7.3% in healthy girls, and 5.8% compared to 9.4% in healthy boys. FEV1/FVC increased in early adolescence, but at age 16, was 5.6% lower in male children compared to healthy children, and 5.4% lower in females. The ratio was lower in obese children at all ages but demonstrated the same curvilinear shape as healthy children. In absolute terms, FEV1 grew proportionately more than FVC during early adolescence, so the ratio of FEV1/FVC increased during that period. The curvilinear shape of the curve remained in postbronchodilator testing, though significantly blunted.

CONCLUSIONS

FEV1/FVC is lower in children with persistent asthma than healthy children, but the "Shepherd's Hook" pattern is preserved. This was true in obese patients with asthma, although their FEV1/FVC ratios were lower throughout all stages of childhood and adolescence.

Association between Weight for Length and the Severity of Respiratory Morbidity in Preterm Infants

Association Between Weight for Length and the Severity of Respiratory Morbidity in Preterm Infants.

OBJECTIVE

To determine whether higher weight-to-length z-scores after 32 weeks of gestation are associated with higher pulmonary scores (PSs) in preterm infants requiring respiratory support using a prospective observational study.

METHODS

Infants born at <30 weeks, with a post-menstrual age (PMA) of 30-33 weeks, were enrolled. The infant's weight, length, and head circumference were measured weekly. Data on calories/kg/d, protein g/kg/d, weight-for-length percentiles, z-scores, and BMI at 33 through 40 weeks PMA were collected. The PS was calculated.

RESULTS

We analyzed 91 infants. The mean gestational age was 26.9 ± 1.7 weeks. The mean birthweight was 0.898 ± 0.238 kgs. They were predominantly African American (81.3%) and girls (56%). Postnatal steroids were administered in 26.4% of the infants. The mean duration of invasive ventilation was 19.23 days ± 28.30 days. There was a significant association between the PS and W/L z-score (p < 0.0001). For every one-unit increase in W/L z-score, the PS increased by 0.063. There was a significant association between the PS and W/L percentile (p = 0.0017), as well as BMI (p ≤ 0.0001). For every unit increase in W/L percentile, the PS increased by 0.002, and for a unit increase in BMI, the PS increased by 0.04. The association remained significant after postnatal steroid use, sex, and corrected and birth gestational ages were included in the regression analysis. Nutrition did not affect the anthropometric measurements.

CONCLUSIONS

Our study is the first to demonstrate that a higher BMI and W/L may adversely affect the respiratory severity in preterm infants. Studies with larger sample sizes are needed to confirm our findings.

Impact of obesity in asthma: Possible future therapies

Obesity is one of the factors associated with the severity of asthma. Obesity is associated with aggravation of the pathophysiology of asthma, including exacerbations, airway inflammation, decreased pulmonary function, and airway hyperresponsiveness. The present review addresses the characteristics of asthma with obesity, focusing especially on the heterogeneity caused by the degree of type 2 inflammation, sex differences, the onset of asthma, and race differences. To understand the severity mechanisms in asthma and obesity, such as corticosteroid resistance, fatty acids, gut microbiome, and cytokines, several basic research studies are evaluated. Finally, possible future therapies, including weight reduction, microbiome-targeted therapies, and other molecular targeted therapies are addressed. We believe that the present review will contribute to better understanding of the severity mechanisms and the establishment of novel treatments for severe asthma patients with obesity.

Obesity-Associated Non-T2 Mechanisms in Obese Asthmatic Individuals

Obesity and asthma are two common health issues that have shown increased prevalence in recent years and have become a significant socioeconomic burden worldwide. Obesity increases asthma incidence and severity. Obese asthmatic individuals often experience increased exacerbation rates, enhanced airway remodeling, and reduced response to standard corticosteroid therapy. Recent studies indicate that obesity-associated non-T2 factors such as mechanical stress, hyperinsulinemia, systemic inflammation, adipose tissue mediators, metabolic dysregulation, microbiome dysbiosis, and high-fat-diet are responsible for increased asthma symptoms and reduced therapeutic response in obese asthmatic individuals. This manuscript reviews the recent findings highlighting the role of obesity-associated factors that contribute to airway hyper-reactivity, airway inflammation and remodeling, and immune cell dysfunction, consequently contributing to worsening asthma symptoms. Furthermore, the review also discusses the possible future therapies that might play a role in reducing asthma symptoms by diminishing the impact of obesity-associated non-T2 factors.

Effect of Obesity on Lung Function in the Pediatric and Adult Populations with Asthma: A Review

Obesity and asthma are major global health concerns, particularly in industrialized nations. Obesity has been shown to have detrimental effects on the respiratory system and lung function owing to metabolic issues and immunological consequences. Research has indicated that obese patients with asthma (atopic or T2-high and non-atopic or T2-low) have diminished lung function in terms of functional residual capacity (FRC), residual volume (RV), expiratory reserve volume (ERV), the FEV1/FVC ratio, and FEF 25-75% due to mechanical fat loading on the diaphragm and central adiposity when compared to non-obese asthmatic patients. Therefore, it is plausible that changes in lung function are the result of a combination of mechanical (fat loading on the diaphragm, central adiposity, bronchial hyper-reactivity, and an increase in cholinergic tone), environmental (diet and exercise), and inflammatory factors (local and systemic), which can lead to the obesity-related asthma phenotype characterized by severe asthma symptoms, poor response to corticosteroid treatment, loss of lung function, and poor quality of life from an early age.

Obesity-related pediatric asthma: relationships between pulmonary function and clinical outcomes

OBJECTIVE

We hypothesized that children with obesity-related asthma would have worse self-reported asthma control, report an increased number of asthma symptoms and have lower FEV1/FVC associated with worse clinical asthma outcomes compared to children with asthma only.

METHODS

Cross sectional analyses examined two hundred and eighteen (obesity-related asthma = 109, asthma only = 109) children, ages 7-15 that were recruited from clinics and hospitals within the Bronx, NY. Pulmonary function was assessed by forced expiratory volume in the first second (percent predicted FEV1) and the ratio of FEV1 to the forced vital capacity of the lungs (FEV1/FVC). Structural equation modeling examined if pulmonary function was associated with asthma control and clinical outcomes between groups.

RESULTS

Lower percent predicted FEV1 was associated with increased hospitalizations (p = 0.03) and oral steroid bursts in the past 12 months (p = 0.03) in the obesity-related asthma group but not in the asthma only group. FEV1/FVC was also associated with increased hospitalizations (p = 0.02) and oral steroid bursts (p = 0.008) in the obesity-related asthma group but not the asthma only group. Lower FEV1/FVC was associated with the number of asthma symptoms endorsed in the asthma only group but not in the obesity-related asthma group. Percent predicted FEV1 and FEV1/FVC was not associated with asthma control in either group.

CONCLUSIONS

Pulmonary function was associated with oral steroid bursts and hospitalizations but not self-reported asthma control, suggesting the importance of incorporating measures of pulmonary function into the treatment of pediatric obesity-related asthma.

Pediatric obesity and severe asthma: Targeting pathways driving inflammation

Asthma affects more than 300 million people of all ages worldwide, including about 10-15% of school-aged children, and its prevalence is increasing. Severe asthma (SA) is a particular and rare phenotype requiring treatment with high-dose inhaled corticosteroids plus a second controller and/or systemic glucocorticoid courses to achieve symptom control or remaining "uncontrolled" despite this therapy. In SA, other diagnoses have been excluded, and potential exacerbating factors have been addressed. Notably, obese asthmatics are at higher risk of developing SA. Obesity is both a major risk factor and a disease modifier of asthma in children and adults: two main "obese asthma" phenotypes have been described in childhood with high or low levels of Type 2 inflammation biomarkers, respectively, the former characterized by early onset and eosinophilic inflammation and the latter by neutrophilic inflammation and late-onset. Nevertheless, the interplay between obesity and asthma is far more complex and includes obese tissue-driven inflammatory pathways, mechanical factors, comorbidities, and poor response to corticosteroids. This review outlines the most recent findings on SA in obese children, particularly focusing on inflammatory pathways, which are becoming of pivotal importance in order to identify selective targets for specific treatments, such as biological agents.

Are Mid to Late Adolescents with Asthma Ready for Transition of Care? A Qualitative Study

This qualitative descriptive study explores experiences and perspectives of mid-to-late adolescents about growing up with asthma, and the roles of parents and providers as they transition. Purposeful sampling was used to recruit and enroll adolescents aged 16-20 years with asthma. Forty-one adolescents participated in a focus group or individual interview, and content analysis was conducted to analyze the data. The mean age of participants was 17.7 years, the majority (56%) of whom were Black. Themes that emerged included concerns about becoming an adult with asthma and its self-management, parental involvement, and communication with providers. Adolescents felt burdened by asthma, few considered becoming adults with asthma, and their future outlook was pessimistic with concerns related to worsening symptoms, inadequacy in symptom self-management and limitations on career choices due to asthma. Deficiencies in self-management were noted, parents still played major roles in adolescents' asthma care, and transition of care was seldom discussed with the providers. Mid-to-late adolescents with asthma are inadequately prepared for transition of care, and parents and providers insufficiently engage adolescents in the preparation. Parent, provider, and adolescent partnership is critical to achieve adolescent readiness for independence in asthma management and to ensure proper asthma care continuity post transition.

Obesity and Adipose Tissue Dysfunction: From Pediatrics to Adults

Obesity is a growing health problem that affects both children and adults. The increasing prevalence of childhood obesity is associated with comorbidities such as cardiovascular disease, type 2 diabetes and metabolic syndrome due to chronic low-grade inflammation present at early stages of the disease. In pediatric patients suffering from obesity, the role of epigenetics, the gut microbiome and intrauterine environment have emerged as causative factors Interestingly, pediatric obesity is strongly associated with low birth weight. Accelerated weight gain oftentimes occurs in these individuals during the post-natal period, which can lead to increased risk of adiposity and metabolic disease. The pathophysiology of obesity is complex and involves biological and physiological factors compounded by societal factors such as family and community. On a cellular level, adipocytes contained within adipose tissue become dysregulated and further contribute to development of comorbidities similar to those present in adults with obesity. This review provides an overview of the current understanding of adipose tissue immune, inflammatory and metabolic adaptation of the adipose tissue in obesity. Early cellular changes as well as the role of immune cells and inflammation on the progression of disease in pivotal pediatric clinical trials, adult studies and mouse models are emphasized. Understanding the initial molecular and cellular changes that occur during obesity can facilitate new and improved treatments aimed at early intervention and subsequent prevention of adulthood comorbidities.

Thinness negatively affects lung function among Sri Lankan children

Background

There have been conflicting findings on the effect of body mass index (BMI) on lung functions in children. Therefore, we studied the relationship between spirometry parameters and BMI among healthy Sri Lankan school children aged 5–7 years.

Methods

A cross-sectional study was conducted among 296 school children (5–7-year-old) without apparent lung disease. Recruitment was done with stratified random sampling. Spirometry parameters, FEV₁, FVC, PEFR, and FEV₁/FVC ratio were determined. The acceptable and reproducible spirometry recordings were included in the analysis. Simple and multivariate linear regression analysis examined possible associations of lung function parameters with BMI, socio‐demographic variables and indoor risk factors. Also, the mediator effect of gender on lung function through BMI was explored.

Results

The participants’ mean age (SD) was 6.4 (0.65) years. One-third were thin/severely thin (37%). A statistically significant difference in FVC (p = 0.001) and FEV₁ (p = 0.001) was observed between BMI groups (obesity/overweight, normal, and thinness). Yet, PEFR or FEV₁/FVC did not significantly differ among BMI groups (p = 0.23 and p = 0.84). Multivariate regression analysis showed that FEV₁ and FVC were significantly associated with BMI, child’s age, gender, family income, father’s education, having a pet, and exposure to mosquito coil smoke. Interaction between gender and BMI for lung functions was not significant. The thin children had significantly lower FVC (OR: -0.04, 95%CI: -0.077, -0.012, p = 0.008) and FEV₁ (OR: -0.04, 95%CI: -0.075, -0.014, p = 0.004) than normal/overweight/obese children. Family income demonstrated the greatest effect on lung functions; FVC and FEV₁ were 0.25L and 0.23L smaller in low-income than the high-income families.

Conclusion

Lower lung function parameters (FVC and FEV₁) are associated with thinness than normal/overweight/obese dimensions among children without apparent lung disease. It informs that appropriate nutritional intervention may play a role in improving respiratory health.

Association between obesity and lung function in South African adolescents of African Ancestry

Background

There is a growing body of literature on the increasing prevalence of obesity in adolescents of Sub-Saharan African ancestry. However, limited data is available on the impact of obesity on pulmonary function. This study assessed the relationship between obesity and lung function in South African adolescents of African ancestry.

Methods

This was a cross-sectional study involving 10–14 year old adolescents recruited from middle schools of the Eastern Cape Province of South Africa. Anthropometric measurements were performed. Body mass index (BMI) was converted to percentiles for age and sex and used to classified obesity. Spirometry was performed to assess lung function. Chi-square test of association and binary regression analysis were used to assess the relationship between obesity and airway obstruction. Adjusted linear regression was used to determine the relationship between obesity and lung function parameters.

Results

A total of 540 adolescents were recruited for the study among which 77 (14.3%) were obese. Lung function parameters: forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) were higher (p < 0.001) in obese than in non-obese adolescents while peak expiratory flow (PEF) % and FEV₁/FVC ratio were lower (p < 0.05) in obese than non-obese adolescents. Obesity was associated (χ2 = 9.614; p < 0.01) with airway obstruction and obese adolescents were over 1.5 times more likely to have pulmonary obstruction (OR: 1.57; p < 0.05) than their non-obese counterparts. Anthropometric measures were positively associated (p < 0.05) with FVC, FEV1, PEF and/or FEV_25-75 but negatively associated with FEV₁/FVC ratio.

Conclusions

Obesity was associated with airway obstruction in South Africa adolescents of African ancestry.

Relationship of Nutritional Status and Spirometric Parameters in Children with Bronchial Asthma

The potential mechanisms of bronchial asthma (BA) negative modification under the influence of obesity are currently being actively studied. However, at present, the effect of nutritional status on bronchial obstruction in children with BA cannot be considered established. In this regard, the purpose of this work was to study the relationship of spirometric parameters reflecting bronchial patency with nutritional status in children with asthma.

School-Age Obese Asthmatic Children have Distinct Lung Function Measures From Lean Asthmatics and Obese Children

Background: The lung functions of children with obese asthma seem to be distinct from those of obese children or lean asthmatics.Aim: To measure baseline lung function, exercise-induced bronchoconstriction (EIB), and bronchial hyperreactivity (BHR) in school-age obese asthmatics (OA group) and to compare the data with obese children (O group), lean asthmatics (A group), and healthy controls (H group).Methods: One hundred seventy school-age children were enrolled in this prospective cross-sectional study. Baseline fractionated exhaled nitric oxide (FeNO), and baseline, post-exercise (post-E), and post-bronchodilation (post-BD) impulse oscillometry (IOS) and spirometry tests were performed. EIB and BHR were evaluated based on the difference (Δ) in post-E - baseline, and post-BD - baseline values.Results: The mean FeNO level was higher in the OA group than in the other groups (p = 0.002). Baseline zR5 and R5-20 were higher (p = 0.013 and p = 0.044), but zFEF25-75 was lower (p < 0.01), in the OA group. ΔPost-E - baseline zFEV1 was lower in the A group (p = 0.003) but was higher in the OA group (p = 0.014) than the other groups. ΔPost-BD - baseline zFEV1 was lower in the H group compared to the other three groups (p = 0.004), but no significant difference was observed among the O, A, and OA groups (p > 0.05).Conclusion: A higher airway inflammation (high FeNO), peripheral airway resistance (high zR5 and zR5-20) and a lower peripheral airway flow (low FEF25-75) were observed at baseline measurement in school-age obese asthmatics compared to lean asthmatics and obese children. Obese asthmatics had no EIB but exhibited a similar BHR to that of asthmatics.

The impact of obesity on immune function in pediatric asthma

PURPOSE OF REVIEW

Pediatric obese asthma is a complex disease that remains poorly understood. The increasing worldwide incidence of both asthma and obesity over the last few decades, their current high prevalence and the challenges in treating obese asthmatic patients all highlight the importance of a better understanding of the pathophysiological mechanisms in obese asthma. While it is well established that patients with obesity are at an increased risk of developing asthma, the mechanisms by which obesity drives the onset of asthma, and modifies existing asthma, remain unclear. Here, we will focus on mechanisms by which obesity alters immune function in asthma.

RECENT FINDINGS

Lung parenchyma has an altered structure in some pediatric obese asthmatics, known as dysanapsis. Central adiposity is linked to reduced pulmonary function and a better predictor of asthma risk in children than BMI. Obesity in young children is associated with an increased risk of developing asthma, as well as early puberty, and hormonal alterations are implicated in obese asthma. Obesity and asthma each yield immunometabolic dysregulation separately and we are learning more about alterations in these pathways in pediatric obese asthma and the potential impact of bariatric surgery on those processes.

SUMMARY

The recent progress in clarifying the connections between childhood obesity and asthma and their combined impacts on immune function moves us closer to the goals of improved understanding of the pathophysiological mechanisms underpinning obese asthma and improved therapeutic target selection. However, this common inflammatory disease remains understudied, especially in children, and much remains to be learned.

Obesity and asthma

Obesity has been well recognized as an important comorbidity in patients with asthma, representing a unique phenotype and endotype. This association indicates a close relationship between metabolic and inflammatory dysregulation. However, the detailed organ-organ, cellular, and molecular interactions are not completely resolved. Because of that, the relationship between obesity and asthma remains unclear. In this article, clinical and epidemiological studies, as well as data from experimental animal work, are being summarized to provide a state of the art update on this important topic. Much more work is needed, particularly mechanistic, to fully understand the interaction between obesity and asthma and to develop novel preventive and therapeutic strategies.

A comparative study of clinical profile and symptom control in overweight and normal weight school-age children with mild persistent asthma

OBJECTIVES

To find out the proportion of children with poor symptom control in overweight/obese and normal weight children with mild persistent asthma and to know the sociodemographic and clinical correlates of poor symptom control in them.

MATERIALS AND METHODS

Children aged 6 to 12 years with mild persistent asthma with BMI Z score for age and sex more than +1 Z score on WHO BMI Z score chart for age and sex formed the cases. Age- and sex-matched asthmatics with BMI Z score for age and sex between -2 Z and +1 Z score formed the controls. FEV1, FEV1/FVC were measured in both groups using Care Fusion Jaeger spirometer. Symptom control was assessed by ACT score. Statistical analysis was done using SPSS version 19 and Vassarstats.

RESULTS

The proportion of children with poor control was 19.1% in the overweight/obese group and 23.4% in the normal weight group. There was no significant correlation between BMI and symptom control as assessed by the ACT score. Overweight/obese children with good control showed a slightly lower FEV1/FVC ratio and higher median eosinophil count compared to children with normal weight. Gastroesophageal reflux and allergic rhinitis were more commonly seen in overweight/obese children. In the poor control group, FEV1, FEV1/FVC, and median eosinophil counts were not significantly different between overweight/obese and normal weight group but were less when compared to good control group.

CONCLUSION

The proportion of poor symptom control was not high in overweight/obese asthmatic children compared to normal weight asthmatic children. No significant risk factors for poor symptom control could be identified in our study for either of the groups.

Childhood Obesity and Respiratory Diseases: Which Link?

Prevalence of childhood obesity is progressively increasing, reaching worldwide levels of 5.6% in girls and of 7.8% in boys. Several evidences showed that obesity is a major preventable risk factor and disease modifier of some respiratory conditions such as asthma and Obstructive Sleep Apnea Syndrome (OSAS). Co-occurrence of asthma and obesity may be due to common pathogenetic factors including exposure to air pollutants and tobacco smoking, Western diet, and low Vitamin D levels. Lung growth and dysanapsis phenomenon in asthmatic obese children play a role in impaired respiratory function which appears to be different than in adults. Genes involved in both asthma and obesity have been identified, though a gene-by-environment interaction has not been properly investigated yet. The identification of modifiable environmental factors influencing gene expression through epigenetic mechanisms may change the natural history of both diseases. Another important pediatric respiratory condition associated with obesity is Sleep-Disordered Breathing (SDB), especially Obstructive Sleep Apnea Syndrome (OSAS). OSAS and obesity are linked by a bidirectional causality, where the effects of one affect the other. The factors most involved in the association between OSAS and obesity are oxidative stress, systemic inflammation, and gut microbiota. In OSAS pathogenesis, obesity's role appears to be mainly due to mechanical factors leading to an increase of respiratory work at night-time. However, a causal link between obesity-related inflammatory state and OSAS pathogenesis still needs to be properly confirmed. To prevent obesity and its complications, family education and precocious lifestyle changes are critical. A healthy diet may lead to an improved quality of life in obese children suffering from respiratory diseases. The present review aimed to investigate the links between obesity, asthma and OSAS, focusing on the available evidence and looking for future research fields.

Effect of Obesity on Asthma Severity in Urban School Children of Kanpur, India: An Analytical Cross-Sectional Study

The prevalence of both Obesity and Asthma is increasing worldwide. Various epidemiological data has linked obesity with the development and severity of asthma in children. The aim of this study was to assess if any relationship exists between obesity and asthma in children. The study population included school children aged 5 to 18 years. A total of 320 asthma cases and 300 controls were included in our study. Association analysis of obesity and asthma based on epidemiological basis was measured. Out of 320 cases, 61 children were found to have moderate persistent asthma. Out of 61 moderate persistent asthma cases, 50 children were selected randomly and divided into two groups. Group I included 25 obese moderate persistent asthmatics and Group II included 25 non-obese moderate persistent asthmatics. Forced expiratory volume in one second (FEV₁), Forced vital capacity (FVC), Forced expiratory flow (FEF_25-75%), Peak expiratory flow (PEF) were measured with spirometry and Peak expiratory flow meter. Statistical analysis was done by Odds ratio and p value. Out of 320 cases, 97 were obese and 223 were non-obese. Out of 300 controls, 46 were obese and 254 were non-obese. Exposure rate for cases and controls were 30.31% and 15.33% respectively. Odds ratio was 2.40. χ² value was 19.56 with p value < 0.05.FEV₁, FVC, FEF_{25-75%, PEF} for Group-1 were 66.3 ± 9.9, 63.5 ± 4.2, 54.2 ± 5.7, 67.4 ± 8.4 respectively and FEV₁, FVC, FEF_25-75%, PEF for Group-2 were 74.07 ± 3.5, 77.4 ± 7.2, 60.1 ± 2.1, 71.6 ± 2.4 respectively and p values were < 0.001, < 0.001, < 0.001, < 0.05 respectively which is statistically significant. Children who are obese are more likely to develop severe asthma than those who were not obese.

Correction to: Effect of Obesity on Asthma Severity in Urban School Children of Kanpur, India: An Analytical Cross-Sectional Study

The original publication of the article [1] unfortunately contain mistakes. The quotations from various sources [2-6] in the Discussion section should have been embraced by quotation marks.

Pediatric obesity-related asthma: A prototype of pediatric severe non-T2 asthma

Childhood obesity contributes to many diseases, including asthma. There is literature to suggest that asthma developing as a consequence of obesity has a nonallergic or non-T2 phenotype. In this review, obesity-related asthma is utilized as a prototype of non-T2 asthma in children to discuss several nonallergic mechanisms that underlie childhood asthma. Obesity-related asthma is associated with systemic T helper (Th)1 polarization occurring with monocyte activation. These immune responses are mediated by insulin resistance and dyslipidemia, metabolic abnormalities associated with obesity, that are themselves associated with pulmonary function deficits in obese asthmatics. As in other multifactorial diseases, there is both a genetic and an environmental contribution to pediatric obesity-related asthma. In addition to genetic susceptibility, differential DNA methylation is associated with non-T2 immune responses in pediatric obesity-related asthma. Initial investigations into the biology of non-T2 immune responses have identified the upregulation of genes in the CDC42 pathway. CDC42 is a RhoGTPase that plays a key role in Th cell physiology, including preferential naïve Th cell differentiation to Th1 cells, and cytokine production and exocytosis. Although these novel pathways are promising findings to direct targeted therapy development for obesity-related asthma to address the disease burden, there is evidence to suggest that dietary interventions, including diet modification, rather than caloric restriction alone, decrease disease burden. Adoption of a diet rich in micronutrients, including carotenoids and 25-OH cholecalciferol, a vitamin D metabolite, may be beneficial since these are positively correlated with pulmonary function indices, while being protective against metabolic abnormalities associated with the obese asthma phenotype.

Associations between overweight and obesity and asthma outcomes in urban adolescents

Objective: To examine the prevalence of overweight and obesity in urban adolescents with asthma and to investigate the relationships between anthropometric measures and asthma outcomes including quality of life, asthma control and lung function.Methods: Adolescents with an asthma diagnosis, 12-20 years-old, were recruited from three urban communities in the United States. Spirometry and anthropometric data including height, weight and waist circumferences were collected along with questionnaire data measuring quality of life, asthma control, and medication adherence. Body mass index (BMI) and waist-height ratio (WHtR) were computed.Results: The sample (N = 294) included 48% female and 80% African American. About 50% of the sample were either overweight or obese, and 41% had central obesity. No significant gender interactions with either BMI or WHtR on asthma outcomes were found. Neither BMI nor WHtR predicted quality of life, asthma control or medication adherence, while females had poorer quality of life and asthma control regardless of weight status (p < 0.001). Higher BMI or WHtR predicted higher spirometry values. Regardless of weight status, females had greater percent predicted spirometry values, while raw values (L) were significantly greater in males.Conclusions: High BMI is a common comorbidity among poor, primarily African American, urban adolescents with asthma. The negative impact of being overweight or obese on quality of life or asthma control is yet to be manifested in adolescents. The findings underscore adolescence as an ideal period to safely intervene to reduce excessive body weight, which can prevent the potentially harmful effects of obesity on future asthma outcomes.

Childhood Body Composition Trajectories and Adolescent Lung Function. Findings from the ALSPAC study

Rationale: Body composition changes throughout life may explain the inconsistent associations reported between body mass index and lung function in children. Objectives: To assess the associations of body weight and composition trajectories from 7 to 15 years with lung function at 15 years and lung function growth between 8 and 15 years. Methods: Sex-specific body mass index, lean body mass index, and fat mass index trajectories were developed using Group-Based Trajectory Modeling on data collected at least twice between 7 and 15 years from 6,964 children (49% boys) in the UK Avon Longitudinal Study of Parents and Children birth cohort. Associations of these trajectories with post-bronchodilation lung function parameters at 15 years and with lung function growth rates from 8 to 15 years were assessed using multivariable linear regression models, stratified by sex, in a subgroup with lung function data (n = 3,575). Measurements and Main Results: For all body mass measures we identified parallel trajectories that increased with age. There was no consistent evidence of an association between the body mass index trajectories and lung function measures. Higher lean body mass index trajectories were associated with higher levels and growth rates of FVC, FEV1, and forced expiratory flow, midexpiratory phase in both sexes (e.g., boys in the highest lean body mass index trajectory had on average a 0.62 L [95% confidence interval, 0.44-0.79; P trend < 0.0001] higher FVC at 15 yr than boys in the lowest trajectory). Increasing fat mass index trajectories were associated with lower levels and growth rates of FEV1 and forced expiratory flow, midexpiratory phase only in boys and lower levels of FEV1/FVC in both sexes. Conclusions: Higher lean body mass during childhood and adolescence is consistently associated with higher lung function at 15 years in both sexes, whereas higher fat mass is associated with lower levels of only some lung function parameters.

The etiologic origins for chronic obstructive pulmonary disease

COPD, characterized by long-term poorly irreversible airway limitation and persistent respiratory symptoms, has resulted in enormous challenges to human health worldwide, with increasing rates of prevalence, death, and disability. Although its origin was thought to be in the interactions of genetic with environmental factors, the effects of environmental factors on the disease during different life stages remain little known. Without clear mechanisms and radical cure for it, early screening and prevention of COPD seem to be important. In this review, we will discuss the etiologic origins for poor lung function and COPD caused by specific adverse effects during corresponding life stages, as well as try to find new insights and potential prevention strategies for this disease.

Asthma and obesity in the Middle East region: An overview

This paper aims to cover the current status of asthma and obesity in the Middle East, as well as to introduce the various studies tying the two diseases; further expanding on the proposed mechanisms. Finally, the paper covers recent literature related to sphingolipids and its role in asthma, followed by recommendations and future directions. In preparation of this paper, we searched PubMed and Google Scholar, with no restrictions, using the following terms; asthma, obesity, Middle East, sphingolipids. We also used the reference list of retrieved articles to further expand on the pool of articles that were used for this review.

Pediatric Obesity and the Immune System

Obesity has reached pandemic proportion and represents a major risk for several comorbidities. In addition to metabolic and cardiovascular obesity-related diseases, recent evidence suggested that obesity might affect immune system function. Adipose tissue is considered an endocrine organ that actively secretes cytokines also referred to as "adipokines." Adipokines play an important role in the control of human metabolism. The dysfunctional adipose tissue in obese individuals is characterized by an altered cytokine secretion pattern that promotes chronic low-grade inflammation. Epidemiological evidence highlights the association between obesity and allergic and immune-mediated diseases, such as asthma, allergic rhinitis, rheumatic arthritis, and psoriasis. Less is known about underlying pathogenic mechanisms. However, several recent in vivo and in vitro studies have reported that adipokines are involved in inflammatory and autoimmune disorders by influencing both innate and acquired immune responses. In addition, obesity has been associated with reduced immune surveillance and increased risk of cancer. This paper reviews the evidence regarding the role of adipokines in immune system regulation, with particular emphasis on autoimmune, allergic, and inflammatory disorders. Understanding how obesity affects immune system functions may enable researchers to find new potential therapeutic targets in the management of allergic and autoimmune diseases.

The effect of obesity on lung function

INTRODUCTION

There is a major epidemic of obesity, and many obese patients suffer with respiratory symptoms and disease. The overall impact of obesity on lung function is multifactorial, related to mechanical and inflammatory aspects of obesity. Areas covered: Obesity causes substantial changes to the mechanics of the lungs and chest wall, and these mechanical changes cause asthma and asthma-like symptoms such as dyspnea, wheeze, and airway hyperresponsiveness. Excess adiposity is also associated with increased production of inflammatory cytokines and immune cells that may also lead to disease. This article reviews the literature addressing the relationship between obesity and lung function, and studies addressing how the mechanical and inflammatory effects of obesity might lead to changes in lung mechanics and pulmonary function in obese adults and children. Expert commentary: Obesity has significant effects on respiratory function, which contribute significantly to the burden of respiratory disease. These mechanical effects are not readily quantified with conventional pulmonary function testing and measurement of body mass index. Changes in mediators produced by adipose tissue likely also contribute to altered lung function, though as of yet this is poorly understood.

Expression of vitamin D receptor in bronchial asthma and its bioinformatics prediction

Vitamin D receptors (VDRs) are associated with the occurrence and development of asthma. The aim of the present study was to analyze the secondary structure and B‑cell and T‑cell epitopes of VDR using online prediction software and aid in the future development of a highly efficient epitope‑based vaccine against asthma. Blood samples were collected from peripheral blood of asthmatic children. Reverse transcription quantitative‑polymerase chain reaction (RT‑qPCR) was performed to detect the expression of VDR in the peripheral blood. Mouse models of asthma were established. Hematoxylin and eosin staining was performed to observe the pathological alterations of the lungs of mice. Immunohistochemistry, western blot analysis and RT‑qPCR were performed to detect the expression of VDR in the lungs of asthmatic mice. Online prediction software immune epitope database and analysis resource, SYFPEITHI and linear epitope prediction based on propensity scale and support vector machines were used to predict the B‑cell and T‑cell epitopes and the RasMol and 3DLigandSite were used to analyze the tertiary structure of VDR. RT‑qPCR demonstrated that VDR expression in the peripheral blood of asthmatic children was decreased. Immunohistochemistry, western blotting and RT‑qPCR demonstrated that VDR expression also decreased in the lungs of mouse models of asthma. VDR B‑cell epitopes were identified at 37‑45, 88‑94, 123‑131, 231‑239, 286‑294 and 342‑350 positions of the amino acid sequence and VDR T‑cell epitopes were identified at 125‑130, 231‑239 and 265‑272 positions. A total of six B‑cell epitopes and three T‑cell epitopes for VDR were predicted by bioinformatics, which when validated, may in the future aid in immunological diagnosis and development of a targeted drug therapy for clinical asthma.

Obesity and asthma

Obesity is a vast public health problem and both a major risk factor and disease modifier for asthma in children and adults. Obese subjects have increased asthma risk, and obese asthmatic patients have more symptoms, more frequent and severe exacerbations, reduced response to several asthma medications, and decreased quality of life. Obese asthma is a complex syndrome, including different phenotypes of disease that are just beginning to be understood. We examine the epidemiology and characteristics of this syndrome in children and adults, as well as the changes in lung function seen in each age group. We then discuss the better recognized factors and mechanisms involved in disease pathogenesis, focusing particularly on diet and nutrients, the microbiome, inflammatory and metabolic dysregulation, and the genetics/genomics of obese asthma. Finally, we describe current evidence on the effect of weight loss and mention some important future directions for research in the field.

Overweight, Obesity, and Lung Function in Children and Adults-A Meta-analysis

BACKGROUND

There is conflicting evidence on the effect of obesity on lung function in adults and children with and without asthma. We aimed to evaluate the relation between overweight or obesity and lung function, and whether such relationship varies by age, sex, or asthma status.

METHODS

We searched PubMed, Scopus, CINAHL, Cochrane, and EMBASE for all studies (in English) reporting on obesity status (by body mass index) and lung function, from 2005 to 2017. Main outcomes were forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC, forced expiratory flow between 25th and 75th percentile of the forced vital capacity (FEF25-75), total lung capacity (TLC), residual volume (RV), and functional residual capacity (FRC). Random-effects models were used to calculate the pooled risk estimates; each study was weighed by the inverse effect size variance. For each outcome, we compared overweight or obese ("obese") subjects with those of normal weight.

RESULTS

All measures of lung function were decreased among obese subjects. Obese adults showed a pattern (lower FEV1, FVC, TLC, and RV) different from obese children (more pronounced FEV1/FVC deficit with unchanged FEV1 or FVC). There were also seemingly different patterns by asthma status, in that subjects without asthma had more marked decreases in FEV1, TLC, RV, and FRC than subjects with asthma. Subjects who were obese (as compared with overweight) had even further decreased FEV1, FVC, TLC, RV, and FRC.

CONCLUSIONS

Obesity is detrimental to lung function, but specific patterns differ between children and adults. Physicians should be aware of adverse effects of obesity on lung function, and weight control should be considered in the management of airway disease among the obese.

A review of obesity and asthma across the life span

OBJECTIVE

This literature review aims to compare obese-asthmatic adults and children, and to characterize differences and similarities between the two subgroups from epidemiological, demographical, phenotypical, and physiological perspectives.

METHODS

Literature search was conducted using Pubmed database with "obesity," "asthma," "epidemiology," "cluster analysis," "demography," "mechanics," and ''FeNO'' as search terms.

METHODS

Articles investigating epidemiological, demographic, phenotypical variation, and mechanical aspects of breathing specifically in obese asthmatics were identified. The studies were then divided according to age: children (<18 years of age) and adults (>18 years of age).

RESULTS

Increase in asthma incidence and prevalence is observed in both obese-asthmatic children and adults. Asthma prevalence is greater in adult females regardless of ethnic background, and in men of African American and Hispanic ethnicities. Degree of weight gain and early onset of menarche appears to directly affect asthma severity in adolescent girls and females. Airway hyperresponsiveness and fractional exhaled nitric oxide do not have any positive correlation with high BMI in obese-asthmatic children and adults. Obesity also alters lung mechanics in asthmatics, but the impact is different for children and adults likely due to differential effect of obesity on central and peripheral airway.

CONCLUSION

Existing literature suggests both similarities and differences in obese-asthmatic children and adults. The most pertinent differences are related to gender, ethnicity, and lung functions.

Body mass index status and peripheral airway obstruction in school-age children: a population-based cohort study

BACKGROUND

Few large prospective studies have investigated the impact of body mass index (BMI) on lung function during childhood.

METHODS

Using data collected between 2002 and 2013, we analysed associations between BMI status and lung function (assessed by spirometry) from 8 to 16 years, as well as cross-sectional associations with small airway function (impulse oscillometry) at 16 years in the BAMSE cohort (n=2889). At 16 years, cross-sectional associations with local and systemic inflammation were investigated by analysing FE_NO, blood eosinophils and neutrophils.

RESULTS

Overweight and obesity at 8 years were associated with higher FVC, but lower FEV₁/FVC ratio at 8 and 16 years. In boys, but not girls, obesity at 8 years was associated with a further reduction in FEV₁/FVC between 8 and 16 years. In cross-sectional analyses, overweight and obesity were associated with higher frequency dependence of resistance (R_5-20) and larger area under the reactance curve (AX^0.5) at 16 years. Increased blood neutrophil counts were seen in overweight and obese girls, but not in boys. No association was found between BMI status and FE_NO. Persistent, but not transient, overweight/obesity between 8 and 16 years was associated with higher R_5-20 and AX^0.5 and lower FEV₁/FVC (-2.8% (95% CI -4.1 to -1.2) in girls and -2.7% (95% CI -4.4 to -1.1) in boys) at 16 years, compared with persistent normal weight.

CONCLUSION

In childhood and adolescence, overweight and obesity, particularly persistent overweight, were associated with evidence of airway obstruction, including the small airways.

Insulin resistance and lung function in obese asthmatic pre-pubertal children

BACKGROUND

Recent findings have supposed that the underlying association between the increased prevalence of both asthma and obesity may be insulin resistance (IR).

METHODS

Insulin and glucose serum levels were analyzed to calculate the homeostatic model assessment of insulin resistance (HOMA-IR) for IR in 98 pre-pubertal children. Lung function and allergy status evaluation were performed. The study population was divided into four groups: (1) obese asthmatic children (ObA); (2) normal-weight asthmatic children (NwA); (3) normal-weight non-asthmatic children (Nw) and (4) obese non-asthmatic children (Ob).

RESULTS

Forced expiratory volume in 1 s (FEV1) was slightly lower in obese subjects compared with normal-weight subjects and forced vital capacity (FVC) appeared lower in asthmatics, whereas between non-asthmatics subjects, it was lower in the obese group than in the normal-weight one. The post hoc analysis revealed a statistically significant reduction in FEV1, peak expiratory flow (PEF), forced expiratory flows (FEF) between 50% and 25% of the FVC (FEF50 and FEF25) between ObA and Nw and in FEV1, FVC, PEF, FEF50 and FEF25 between NwA and Nw, but no statistically significant differences of lung function parameters were observed between ObA and NwA. We found an inverse relationship between HOMA-IR and all spirometric parameters, although without any statistical significance. We also observed a significantly lower FVC in insulin-resistant children (HOMA-IR>95th percentile) (p=0.03).

CONCLUSIONS

This study suggests that lung function could be early altered in obese children, already in pre-pubertal age. Although IR should not manifest its effects on lungs in pre-pubertal obese children, the prevention or treatment of obesity in the pre-pubertal period may prevent definitive negative effects on lungs.

Overweight/obesity status in preschool children associates with worse asthma but robust improvement on inhaled corticosteroids

BACKGROUND

Overweight/obesity (OW) is linked to worse asthma and poorer inhaled corticosteroid (ICS) response in older children and adults.

OBJECTIVE

We sought to describe the relationships between OW and asthma severity and response to ICS in preschool children.

METHODS

This post hoc study of 3 large multicenter trials involving 2- to 5-year-old children compared annualized asthma symptom days and exacerbations among normal weight (NW) (body mass index: 10th-84th percentiles) versus OW (body mass index: ≥85th percentile) participants. Participants had been randomized to daily ICS, intermittent ICS, or daily placebo. Simple and multivariable linear regression was used to compare body mass index groups.

RESULTS

Within the group not treated with a daily controller, OW children had more asthma symptom days (90.7 vs 53.2, P = .020) and exacerbations (1.4 vs 0.8, P = .009) thanNW children did. Within the ICS-treated groups, OW and NW children had similar asthma symptom days (daily ICS: 47.2 vs 44.0 days, P = .44; short-term ICS: 61.8 vs 52.9 days, P = .46; as-needed ICS: 53.3 vs 47.3 days, P = .53), and similar exacerbations (daily ICS: 0.6 vs 0.8, P = .10; short-term ICS: 1.1 vs 0.8 days, P = .25; as-needed ICS: 1.0 vs 1.1, P = .72). Compared with placebo, daily ICS in OW led to fewer annualized asthma symptom days (90.7 vs 41.2, P = .004) and exacerbations (1.4 vs 0.6, P = .006), while similar protective ICS effects were less apparent among NW.

CONCLUSIONS

In preschool children off controller therapy, OW is associated with greater asthma impairment and exacerbations. However, unlike older asthmatic patients, OW preschool children do not demonstrate reduced responsiveness to ICS therapy.

Obesity disproportionately impacts lung volumes, airflow and exhaled nitric oxide in children

Background

The current literature focusing on the effect of obesity and overweight on lung function and fraction of exhaled nitric oxide (FeNO) in children, particularly among healthy children of non-European descent, remains controversial. Furthermore, whether the relationship of obesity and overweight with lung function and FeNO in children is modified by atopy is unclear. The objective of this study was to examine the effect of excess weight on lung function parameters and FeNO among Asian children, with a particular focus on exploring the potential effect modification by atopy.

Methods

We investigated the effect of excess weight on lung function and FeNO in a population sample of 1,717 children aged 5 to 18 years and explored the potential modifying effect of atopy.

Results

There were positive associations of body mass index (BMI) z-score with forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), peak expiratory flow (PEF), and forced expiratory flow at 25–75% (FEF_25-75) (all P<0.001), after controlling for confounders. The beta coefficient for FEV₁ (0.084) was smaller than that for FVC (0.111). In contrast, a negative association was found between BMI z-score and FEV₁/FVC ratio (P<0.001) and FeNO (P = 0.03). A consistent pattern of association for lung function variables was observed when stratifying by atopy. There was a negative association of BMI z-score with FeNO in atopic subjects (P = 0.006), but not in non-atopic subjects (P = 0.46).

Conclusions

Excess weight disproportionately impacts lung volumes and airflow in children from the general population, independent of atopic status. Excess weight inversely affects FeNO in atopic but not in non-atopic children.

Pulmonary function and nutritional morbidity in children and adolescents with congenital diaphragmatic hernia

BACKGROUND

Malnutrition is common among congenital diaphragmatic hernia (CDH) survivors and may result from elevated respiratory effort. We evaluated body mass index (BMI), measured resting energy expenditure (mREE) and pulmonary function test (PFT) results in children and adolescents with CDH to determine if there is a correlation.

METHODS

With ethics approval (REB# 1000035323), anthropometrics, indirect calorimetry (IC) results and PFTs were collected from patients 5-17years of age during CDH clinic visits between 2000 and 2016. Malnutrition was defined as BMI z-scores <-2.0; mREE (as percent predicted REE) was measured using IC; z-scores for forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) were normal if <-1.64.

STATISTICS

GraphPad Prism 6, San Diego, CA.

RESULTS & DISCUSSION

Of 118 patients who attended clinic, 33 had reproducible PFTs, anthropometrics and IC results. Mean BMI z-score was -0.89±1.47 and 24% of patients were malnourished; mean FVC z-score (-1.32±1.39) was within normal range, whereas mean z-scores for FEV₁ (-2.21±1.68) and FEV₁/FVC ratio (-1.78±0.73) were below normal. A correlation was noted between BMI and PFTs (FEV₁ r=0.70, P<0.0001; FVC r=0.74 P<0.0001). Mean mREE was 112%±12% of expected and 67% of patients were hypermetabolic (mREE<110% predicted). IC results did not correlate with z-scores for either FEV₁ (r=0.10, P=0.57); or FVC (r=0.28, P=0.12).

CONCLUSIONS

These preliminary results suggest that a correlation is present between BMI and lung function in CDH children and adolescents, whereas lung function does not seem to correlate with mREE.

LEVEL OF EVIDENCE

II.

Obesity and Airway Dysanapsis in Children with and without Asthma

RATIONALE

For unclear reasons, obese children with asthma have higher morbidity and reduced response to inhaled corticosteroids.

OBJECTIVES

To assess whether childhood obesity is associated with airway dysanapsis (an incongruence between the growth of the lungs and the airways) and whether dysanapsis is associated with asthma morbidity.

METHODS

We examined the relationship between obesity and dysanapsis in six cohorts of children with and without asthma, as well as the relationship between dysanapsis and clinical outcomes in children with asthma. Adjusted odds ratios (ORs) were calculated for each cohort and in a combined analysis of all cohorts; longitudinal analyses were also performed for cohorts with available data. Hazard ratios (HRs) for clinical outcomes were calculated for children with asthma in the Childhood Asthma Management Program.

MEASUREMENTS AND MAIN RESULTS

Being overweight or obese was associated with dysanapsis in both the cross-sectional (OR, 1.95; 95% confidence interval [CI], 1.62-2.35 [for overweight/obese compared with normal weight children]) and the longitudinal (OR, 4.31; 95% CI, 2.99-6.22 [for children who were overweight/obese at all visits compared with normal weight children]) analyses. Dysanapsis was associated with greater lung volumes (FVC, vital capacity, and total lung capacity) and lesser flows (FEV1 and forced expiratory flow, midexpiratory phase), and with indicators of ventilation inhomogeneity and anisotropic lung and airway growth. Among overweight/obese children with asthma, dysanapsis was associated with severe disease exacerbations (HR, 1.95; 95% CI, 1.38-2.75) and use of systemic steroids (HR, 3.22; 95% CI, 2.02-5.14).

CONCLUSIONS

Obesity is associated with airway dysanapsis in children. Dysanapsis is associated with increased morbidity among obese children with asthma and may partly explain their reduced response to inhaled corticosteroids.

Sex Differences in the Relationship between Fitness and Obesity on Risk for Asthma in Adolescents

OBJECTIVE

To evaluate the relationship of fitness and obesity on asthma risk in adolescent girls and boys.

STUDY DESIGN

A cross-sectional assessment of participants 12-19 years of age was conducted by the use of data from the 1999-2004 National Health and Nutrition Examination Survey. Participants completed cardiorespiratory fitness testing, body composition measurements, and respiratory questionnaires.

RESULTS

A total of 4828 participants were included. Overweight/obesity was associated with increased odds of history of asthma (aOR 1.63, 95% CI 1.16-2.30), current asthma (aOR 1.73, 95% CI 1.13, 2.64), and wheezing (aOR 1.40, 95% CI 1.03-1.91) in girls. Overweight/obesity also was associated with increased odds of asthma attacks (aOR 2.67, 95% CI 1.56-4.65) and wheezing related to exercise (aOR 1.60, 95% CI 1.07-2.38) in girls. High fitness was associated with lower odds of asthma-related visits to the emergency department (aOR 0.24, 95% CI 0.07-0.89), wheezing-related medical visits (aOR 0.31, 95% CI 0.13-0.75), wheezing-related missed days (aOR 0.14, 95% CI 0.06-0.33), and wheezing related to exercise (aOR 0.43, 95% CI 0.24-0.76) in boys.

CONCLUSION

Overweight/obesity is associated with increased asthma prevalence and morbidity in girls but not in boys, independent of fitness. High fitness is associated with decreased rates of asthma morbidity in boys but not in girls, independent of weight status. Obesity and fitness may each influence asthma onset and severity in different ways for girls compared with boys.

Obesity increases the prevalence and the incidence of asthma and worsens asthma severity

BACKGROUND & AIMS

We aimed to explore the association between obesity and asthma prevalence, incidence and severity.

METHODS

The study included 32,644 adults, 52.6% female, from a representative sample of the 4th Portuguese National Health Survey. The following asthma definitions were used: ever asthma (ever medical doctor asthma diagnosis), current asthma (asthma within the last 12 months), current persistent asthma (required asthma medication within the last 12 months), current severe asthma (attending an emergency department because of asthma within the last 12 months), and incident asthma (asthma diagnosis within the last 12 months). Body mass index was calculated based on self-reported weight and height and categorised according to WHO classification. Logistic regression models adjusted for confounders were performed.

RESULTS

Prevalence of ever asthma was 5.3%, current asthma 3.5%, current persistent asthma 3.0%, current severe asthma 1.4%, and incident asthma 0.2%. Prevalence of obesity was 16%, overweight 37.6%, normal weight 44.6% and underweight 0.2%. Being overweight, obesity class I and II, and obesity class III were associated with an OR (95% CI) with ever asthma 1.22 (1.21-1.24), 1.39 (1.36-1.41), 3.24 (3.08-3.40) respectively; current asthma 1.16 (1.14-1.18), 1.86 (1.82-1.90), 4.73 (4.49-4.98) respectively; current persistent asthma 1.08 (1.06-1.10), 2.06 (2.01-2.10), 5.24 (4.96-5.53), and current severe asthma 1.36 (1.32-1.40), 1.50 (1.45-1.55) and 3.70 (3.46-3.95), respectively. Considering the incidence of asthma, obesity more than quadrupled the odds (OR = 4.46, 95% CI 4.30, 4.62).

CONCLUSION

Obesity is associated in a dose dependent way with an increase of prevalent and incident asthma, and it seems to increase the odds of a more persistent and severe asthma phenotype independently of socio-demographic determinants, physical activity, and dietary patterns. Our results provide rational for future lifestyle intervention studies for weight reduction in the obesity-asthma phenotype.

Circulating MicroRNAs: Association with Lung Function in Asthma

BACKGROUND

MicroRNAs are key transcriptional and network regulators previously associated with asthma susceptibility. However, their role in relation to asthma severity has not been delineated.

OBJECTIVE

We hypothesized that circulating microRNAs could serve as biomarkers of changes in lung function in asthma patients.

METHODS

We isolated microRNAs from serum samples obtained at randomization for 160 participants of the Childhood Asthma Management Program. Using a TaqMan microRNA array containing 754 microRNA primers, we tested for the presence of known asthma microRNAs, and assessed the association of the individual microRNAs with lung function as measured by FEV1/FVC, FEV1% and FVC%. We further tested the subset of FEV1/FVC microRNAs for sex-specific and lung developmental associations.

RESULTS

Of the 108 well-detected circulating microRNAs, 74 (68.5%) had previously been linked to asthma susceptibility. We found 22 (20.3%), 4 (3.7%) and 8 (7.4%) microRNAs to be associated with FEV1/FVC, FEV1% and FVC%, respectively. 8 (of 22) FEV1/FVC, 3 (of 4) FEV1% and 1 (of 8) FVC% microRNAs had functionally validated target genes that have been linked via genome wide association studies to asthma and FEV1 change. Among the 22 FEV1/FVC microRNAs, 9 (40.9%) remain associated with FEV1/FVC in boys alone in a sex-stratified analysis (compared with 3 FEV1/FVC microRNAs in girls alone), 7 (31.8%) were associated with fetal lung development, and 3 (13.6%) in both. Ontology analyses revealed enrichment for pathways integral to asthma, including PPAR signaling, G-protein coupled signaling, actin and myosin binding, and respiratory system development.

CONCLUSIONS

Circulating microRNAs reflect asthma biology and are associated with lung function differences in asthmatics. They may represent biomarkers of asthma severity.

Relationship Between Obesity and Asthma Control in Children Aged 4-18 years

OBJECTIVE

To analyze the relationship between obesity and asthma control in a group of patients with asthma.

METHODS

In this prospective study, body mass index (BMI) values of 200 asthma patients aged 4-18 y who had been regularly followed up by Kartal Education and Research Hospital Pediatric Asthma Outpatient Clinic were calculated. Asthma control test (ACT) and asthma control questionnaire (ACQ) were performed. The degrees of asthma control were evaluated with regard to BMI values in consideration of the data obtained.

RESULTS

The lowest and the highest BMI values were 12.4 and 30.0 kg/m(2), respectively (mean 18.1 ± 2.9). Of the total 200 children, 110 were boys and 90 were girls. It was found that 17 % of the patients were overweight and 16 % obese. ACT results showed that 72 patients had controlled asthma, 102 patients had partially controlled asthma and 26 patients had uncontrolled asthma. According to ACQ results, 165 patients had controlled asthma, 17 patients had partially controlled asthma and 18 patients had uncontrolled asthma.

CONCLUSIONS

Thus, it was found that there was no statistically significant difference between asthma control degrees of obese and non-obese patients. In other words, obesity did not affect the asthma control level.

Association of obesity and severity of acute asthma exacerbations in Filipino children

BACKGROUND

Increased body mass index (BMI) may be a risk factor for the development and severity of asthma. However, the effect of obesity on asthma exacerbations is unclear.

OBJECTIVE

To examine the association of obesity and the severity of acute asthma exacerbations.

METHODS

A retrospective cohort of children aged 5 to 18 years who were seen in the emergency department and admitted for acute asthma exacerbation from 2009 to 2011 was reviewed. Weight and height data to compute the BMI were taken from the medical record review. The Centers for Disease Control and Prevention BMI-for-age growth charts for boys and girls aged 2 to 20 years were used to classify underweight, normal, overweight, and obese. Severity of asthma exacerbations into mild, moderate, or severe was determined using criteria by the Global Initiative for Asthma 2010. The χ(2) test of association or the Fisher exact probability test for small samples was used to determine the association between nutritional status and severity of asthma exacerbations.

RESULTS

Of the 303 cases reviewed, most were boys with a mean (SD) age of 10 (3.8) years. The prevalence of overweight and obese children admitted for acute asthma exacerbation was 21% and 28%, respectively. No significant difference was found in the severity of asthma exacerbations, with 82.9% of the nonobese group and 86.8% of the overweight-obese group having moderate-to-severe exacerbation (likelihood ratio, 0.879; 95% CI, 0.42-0.41; P = .88).

CONCLUSION

Our findings suggest that the severity of acute asthma exacerbations was not affected by increased BMI.

Atopy, but not obesity is associated with asthma severity among children with persistent asthma

BACKGROUND AND OBJECTIVE

Obesity is associated with an increased risk of asthma in children. Atopic sensitization is a major risk factor for asthma including severe asthma in children. It is unclear if obesity is associated with worse asthma control or severity in children and how its effects compare to atopy. We sought to examine relationships of weight status and atopy to asthma control and severity among a population of predominantly low income, minority children and adolescents with persistent asthma.

METHODS

A cross-sectional analysis of 832 children and adolescents, age range 5-17 years, with persistent asthma was performed. Clinical assessments included asthma questionnaires of symptoms, asthma severity score, health care utilization and medication treatment step, lung function testing, and skin prick testing as well as measures of adiposity. Data were collected between December 2010 and August 2014 from Johns Hopkins Hospital in Baltimore, MD and Children's Hospital of Boston, MA.

RESULTS

Obesity was not associated with worse asthma control or severity in this group of predominantly low income, minority children and adolescents with persistent asthma. However, a greater degree of atopy was associated with lower lung function, higher asthma severity score, and higher medication treatment step.

CONCLUSION

Atopy may be a more important risk factor for asthma severity than obesity among low-income minority children and adolescents with persistent asthma living in Northeastern cities in the United States.

Pediatric Obesity-Related Asthma: The Role of Metabolic Dysregulation

The burden of obesity-related asthma among children, particularly among ethnic minorities, necessitates an improved understanding of the underlying disease mechanisms. Although obesity is an independent risk factor for asthma, not all obese children develop asthma. Several recent studies have elucidated mechanisms, including the role of diet, sedentary lifestyle, mechanical fat load, and adiposity-mediated inflammation that may underlie the obese asthma pathophysiology. Here, we review these recent studies and emerging scientific evidence that suggest metabolic dysregulation may play a role in pediatric obesity-related asthma. We also review the genetic and epigenetic factors that may underlie susceptibility to metabolic dysregulation and associated pulmonary morbidity among children. Lastly, we identify knowledge gaps that need further exploration to better define pathways that will allow development of primary preventive strategies for obesity-related asthma in children.

Obesity, Asthma, and Exercise in Child and Adolescent Health

Obesity increases the risk of asthma throughout life but the underlying mechanisms linking these all too common threats to child health are poorly understood. Acute bouts of exercise, aerobic fitness, and levels of physical activity clearly play a role in the pathogenesis and/or management of both childhood obesity and asthma. Moreover, both obesity and physical inactivity are associated with asthma symptomatology and response to therapy (a particularly challenging feature of obesity-related asthma). In this article, we review current understandings of the link between physical activity, aerobic fitness and the asthma-obesity link in children and adolescents (e.g., the impact of chronic low-grade inflammation, lung mechanics, and direct effects of metabolic health on the lung). Gaps in our knowledge regarding the physiological mechanisms linking asthma, obesity and exercise are often compounded by imprecise estimations of adiposity and challenges of assessing aerobic fitness in children. Addressing these gaps could lead to practical interventions and clinical approaches that could mitigate the profound health care crisis of the increasing comorbidity of asthma, physical inactivity, and obesity in children.

Gastro-oesophageal reflux and worse asthma control in obese children: a case of symptom misattribution?

BACKGROUND

Obese children for unknown reasons report greater asthma symptoms. Asthma and obesity both independently associate with gastro-oesophageal reflux symptoms (GORS). Determining if obesity affects the link between GORS and asthma will help elucidate the obese-asthma phenotype.

OBJECTIVE

Extend our previous work to determine the degree of associations between the GORS and asthma phenotype.

METHODS

We conducted a cross-sectional study of lean (20%-65% body mass index, BMI) and obese (≥95% BMI) children aged 10-17 years old with persistent, early-onset asthma. Participants contributed demographics, GORS and asthma questionnaires and lung function data. We determined associations between weight status, GORS and asthma outcomes using multivariable linear and logistic regression. Findings were replicated in a second well-characterised cohort of asthmatic children.

RESULTS

Obese children had seven times higher odds of reporting multiple GORS (OR=7.7, 95% CI 1.9 to 31.0, interaction p value=.004). Asthma symptoms were closely associated with GORS scores in obese patients (r=0.815, p<0.0001) but not in leans (r=0.291, p=0.200; interaction p value=0.003). Higher GORS scores associated with higher FEV1-per cent predicted (p=0.003), lower airway resistance (R10, p=0.025), improved airway reactance (X10, p=0.005) but significantly worse asthma control (Asthma Control Questionnaire, p=0.007). A significant but weaker association between GORS and asthma symptoms was seen in leans compared with obese in the replicate cohort.

CONCLUSION

GORS are more likely to associate with asthma symptoms in obese children. Better lung function among children reporting gastro-oesophageal reflux and asthma symptoms suggests that misattribution of GORS to asthma may be a contributing mechanism to excess asthma symptoms in obese children.

Nutritional status, adiposity and asthma severity and control in children

AIM

To investigate association between nutritional status, adiposity and asthma severity and control in children.

METHODS

We conducted a case control study at two teaching hospitals in Brazil. Cases were children (3-12 years) with persistent asthma and age-matched controls were those with intermittent asthma. Nutritional status was assessed by body mass index (BMI). Adiposity was assessed by sum of skinfolds and waist circumference (WC). Crude and adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using conditional logistic regression or multinomial logistic regression as appropriate.

RESULTS

Two hundred sixty-eight cases and 126 controls were included. Obesity (>2 BMI z-score for age) was significantly associated with persistent asthma (adjusted OR 2.62; 95% CI 1.39-4.95). There was a significant linear relationship between BMI z-scores (≤1, >1 to ≤2, >2) and risk of having persistent asthma (P = 0.003 for linear trend). Children with WC >90th percentile had a higher risk of persistent asthma when compared with those with WC ≤90th percentile (adjusted OR 3.38; 95% CI 1.26-9.06). No significant difference was found in terms of nutritional status and adiposity between children whose asthma was controlled by inhaled corticosteroids and those requiring inhaled corticosteroids plus other medications for asthma control.

CONCLUSIONS

Obesity measured by BMI and increased abdominal adiposity are significantly associated with risk of persistent asthma but not type of controller medications.

Obesity and atopy

The prevalence of obesity has increased worldwide, and weight gain has been shown to influence the development and clinical expression of various conditions including asthma. The relationships between atopy and obesity remain uncertain, both in adults and in children. Although there are physiopathologic mechanisms which could explain how obesity could influence the immune system and promote the process of sensitization, evidences in favour of a possible role of obesity on the development of atopy have been inconsistent. Furthermore, the bulk of evidence suggests that atopy does not mediate the relationship between obesity and asthma, although in some populations, particularly in children and women, such association has been reported. Such lack of relationship has also been found with rhinoconjunctivitis although it has been observed for atopic dermatitis. Several factors may explain these variable results, including populational or environmental characteristics, socioeconomic status, confounding factors, in addition to sample size, and methodology of the performed studies. The possibility that obesity influences atopy through its effects on sex hormones is suggested by a more frequent link between atopy and obesity in women, particularly postpuberal. Further research should be conducted on the influence of weight gain on atopy and atopic diseases.