Adipokines, asymmetrical dimethylarginine, and pulmonary function in adolescents with asthma and obesity

Isolated respiratory tract microorganisms and clinical characteristics in asthma exacerbation of obese patients: a multicenter study

BACKGROUND

Viral infection is a risk factor for asthma exacerbation (AE). However, bacterial infections related to AE in adults are poorly known. On the other hand, obese patients with asthma have their own clinical and biological characteristics compared with non-obese patients.

METHODS

We investigated the differences in isolated pathogens for AE between obese and non-obese patients with asthma. We included 407 patients with AE from 24 medical centers in Korea. Microorganisms isolated from culture, RT-PCR or serologic tests using lower respiratory tract specimens were retrospectively investigated.

RESULTS

A total of 171 obese and 236 non-obese patients with asthma were included for analysis. Compared to non-obese patients, obese patients were associated with women (77.2% vs. 63.6%), never smoker (82.5% vs. 73.9%), shorter duration of asthma (7.9 ± 8.4 vs. 10.5 ± 10.1 years), less history of pulmonary tuberculosis (8.8% vs. 17.4%), and more comorbidity of allergic rhinitis (48.5% vs. 0.8%). Viral and/or bacterial infections were detected in 205 patients (50.4%) with AE. The numbers of patients with viral only, bacterial only, or both infections were 119, 49, and 37, respectively. The most commonly isolated bacterium was Streptococcus pneumoniae, followed by Pseudomonas aeruginosa and Chlamydia pneumoniae. Obese patients showed a lower incidence of Chlamydia pneumoniae infection. In the non-obese group, bacterial infection, especially Chlamydia pneumoniae infection, was significantly associated with the duration of systemic corticosteroid use (13.6 ± 19.8 vs. 9.7 ± 6.7 days, p = 0.049).

CONCLUSION

Bacterial infection was associated with a longer period of corticosteroid use in the non-obese group. Acute Chlamydia pneumoniae infection was less associated with obese patients with AE. Further well-designed studies are needed to evaluate microorganisms and the efficacy of antibiotics in patients with AE.

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.

Predictive and prognostic value of leptin status in asthma

Asthma is closely associated with inflammation. We evaluated the predictive and prognostic value of leptin status in asthma. We searched the electronic databases for articles that determined the leptin level in asthma cases through May 2020. We compared the differences of leptin level between asthma and non-asthma controls, as well as between severe and mild asthma cases. We also investigated the impact of age and gender on these differences by using meta-regression analysis. 59 studies were included in our pooled analysis. Asthma cases demonstrated significantly higher leptin level than that in non-asthma controls among overall populations (SMD:1.061, 95% CI: 0.784-1.338, p < 10^-4), Caucasians (SMD:0.287, 95% CI: 0.125-0.448, p = 0.001), Asians (SMD:1.500, 95% CI: 1.064-1.936, p < 10^-4) and Africans (SMD: 8.386, 95% CI: 6.519-10.253, p < 10^-4). Severe asthma cases showed markedly higher leptin level than that in mild asthma cases among overall populations (SMD:1.638, 95% CI: 0.952-2.323, p < 10^-4) and Asians (SMD:2.600, 95% CI: 1.854-3.345, p < 10^-4). No significant difference of leptin level between severe and mild asthma was observed in Caucasians (SMD:-0.819, 95% CI: -1.998-0.360, p = 0.173). Cumulative analyses yielded similar results regarding the difference of leptin status between asthma and non-asthma controls, as well as between severe and mild asthma cases among overall populations. Age and male/ female ratio were not associated with the difference of leptin status between asthma and non-asthma controls (coefficient:-0.031, 95% CI: -0.123-0.061, p = 0.495; coefficient:0.172, 95% CI: -2.445-2.789, p = 0.895), as well as between severe and mild asthma cases among overall populations (coefficient:-0.072, 95% CI: -0.208-0.063, p = 0.279; coefficient: 2.373, 95% CI: -0.414-5.161, p = 0.090). Asthma demonstrated significantly higher level of leptin than that in non-asthma controls among overall populations, Caucasians, Asians and Africans. Severe asthma cases showed markedly higher leptin level than that in mild cases among overall populations and Asians. Leptin may be a risk predictor and prognostic marker of asthma. Early monitoring and intervention of leptin may be needed for asthma.

Role of Leptin as a Link between Asthma and Obesity: A Systematic Review and Meta-Analysis

Asthma and obesity are considered as highly prevalent diseases with a great impact on public health. Obesity has been demonstrated to be an aggravating factor in the pathogenesis of asthma. Adipose tissue secretes proinflammatory cytokines and mediators, including leptin, which may promote the development and severity of asthma in obese patients. This study is a systematic review and a meta-analysis based on the relationship between leptin and asthma during obesity. MEDLINE, Cochrane, EMBASE and CINAHL databases were used. Data heterogeneity was analyzed using Cochran’s Q and treatment effect with the DerSimonian and Laird method. Random effect analyses were carried out to test data sensitivity. Asymmetry was estimated using Begg’s and Egger’s tests. All studies showed significant differences in leptin levels. The effect of the measures (p < 0.001), data sensitivity (p < 0.05) and data asymmetry were statistically significant, as well as tBegg’s test (p = 0.010) and Egge’s test (p < 0.001). Despite the existing limiting factors, the results of this study support the relevant role of leptin in the pathophysiology of asthma in obese subjects. Nevertheless, further studies are needed to obtain better insight in the relationship between leptin and asthma in obesity.

The Impact of Dietary Intervention in Obese Children on Asthma Prevention and Control

The prevalence of both asthma and obesity in the pediatric population is steadily increasing, and even the obese-asthma phenotypes are postulated. Obese children with asthma experience more asthma symptoms, more frequent exacerbations, and worse response to treatment; they also report a lower quality of life compared with lean asthmatics. Some of the etiological factors for asthma and obesity may overlap. Perhaps asthma and obesity share a common genetic and immunologic origin. Diet is a compelling modifiable factor in obesity and asthma prevention and control, although the relationship between these two diseases is certainly multifactorial. In this article, we analyze the impact of dietary intervention and weight loss in obese children on asthma prevention and control.

Comparison of Pulmonary Function and Inflammation in Children/Adolescents with New-Onset Asthma with Different Adiposity Statuses

(1) Background: The relationship between obesity and asthma is still uncertain. This study aimed to investigate the effect of overweight/obesity on the pulmonary function of patients with new-onset pediatric asthma and explore the possible causative factors related to concomitant obesity and asthma. (2) Methods: Patients aged 5 to 17 years old with newly diagnosed mild to moderate asthma were recruited from June 2018 to May 2019, from a respiratory clinic in Shanghai, China. Participants were categorized into three groups: normal weight, overweight, and obese asthma. A family history of atopy and patients’ personal allergic diseases were recorded. Pulmonary function, fractional exhaled nitric oxide (FeNO), eosinophils, serum-specific immunoglobulins E (sIgE), serum total IgE (tIgE), and serum inflammatory biomarkers (adiponectin, leptin, Type 1 helper T, and Type 2 helper T cytokines) were tested in all participants. (3) Results: A total of 407 asthma patients (197 normal weight, 92 overweight, and 118 obese) were enrolled. There was a reduction in forced expiratory volume in the first second (FEV1)/forced vital capacity (FVC), FEV1/FVC%, and FEF25–75% in the overweight/obese groups. No difference was found between the study groups in the main allergy characteristics. Leptin levels were higher while adiponectin was lower in asthmatics with obesity. Higher levels of IL-16 were found in overweight/obese asthmatic individuals than in normal-weight individuals. (4) Conclusions: Obesity may have an effect on impaired pulmonary function. While atopic inflammation plays an important role in the onset of asthma, nonatopic inflammation (including leptin and adiponectin) increases the severity of asthma in overweight/obese patients. The significance of different levels of IL-16 between groups needs to be further studied.

DDAH1/ADMA Regulates Adiponectin Resistance in Cerebral Ischemia via the ROS/FOXO1/APR1 Pathway

Dimethylarginine dimethylaminohydrolase 1 (DDAH1) protects against cerebral ischemia injury via regulating the level of asymmetric dimethylarginine (ADMA). This study is aimed at exploring the effect of adiponectin resistance on ADMA-induced neuronal loss in ischemic stroke (IS) and the underlying mechanism. DDAH1 knockout (DDAH1^−/−) and wild-type (DDAH1^+/+) rats underwent middle cerebral artery occlusion/reperfusion (MCAO/R). Plasma and brain adiponectin levels and the expressions of adiponectin receptor 1 (APR1), adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1), adenosine monophosphate-activated protein kinase (AMPK), and phosphorylated AMPK were determined after 24 h, 3 days, and 7 days. Neurological behavior, infarct volume, and adiponectin signaling were evaluated using adiponectin peptide or AdipoRon. The levels of reactive oxygen species (ROS) and Forkhead box O1 (FOXO1) (a transcription factor for APR1) were also assessed. An oxygen-glucose deprivation/reoxygenation (OGD/R) model was established in primary neurons. DDAH1 was overexpressed in neurons, after which FOXO1 expression, ROS production, adiponectin resistance, and cell viability were detected. DDAH1^−/− rats showed no significant difference in adiponectin level in either plasma or brain after MCAO/R in DDAH1^+/+ rats, but downregulated APR1 expression and suppressed adiponectin signaling were observed. AdipoRon, but not adiponectin peptide, attenuated the neurological deficits and adiponectin resistance in DDAH1^−/− rats. ROS accumulation and phosphorylated FOXO1 expression also increased with DDAH1 depletion. Following DDAH1 overexpression, decreased cell viability and inhibited adiponectin signaling induced by OGD/R were alleviated in primary neurons, accompanied by reduced ROS production and phosphorylated FOXO1 expression. Our study elucidated that in IS, DDAH1 protected against adiponectin resistance in IS via the ROS/FOXO1/APR1 pathway.

Obesity Is Associated with Sustained Symptomatology and Unique Inflammatory Features in Children with Asthma

BACKGROUND

Obesity complicates the clinical manifestations of asthma in children. However, few studies have examined longitudinal outcomes or markers of systemic inflammation in obese asthmatic children.

OBJECTIVE

We hypothesized that obese children with asthma would have: (1) poorer clinical outcomes over 12 months, (2) decreased responsiveness to systemic corticosteroid administration, (3) greater markers of systemic inflammation, and (4) unique amino acid metabolites associated with oxidative stress.

METHODS

Children 6 to 17 years of age (lean, N = 257; overweight, N = 99; obese, N = 138) completed a baseline visit and follow-up visit at 12 months. Outcome measures included asthma control, quality of life, lung function, and exacerbations. A subset received intramuscular triamcinolone and were re-evaluated at 7(+7) days. Leptin, adiponectin, C-reactive protein, total cholesterol, interleukin (IL)-1β, IL-6, IL-17, interferon gamma, tumor necrosis factor alpha, monocyte-chemoattractant protein-1, and amino acid metabolites were also quantified in plasma as potential biomarkers of outcomes in obese children.

RESULTS

Obesity was associated with more symptoms, poorer quality life, and more exacerbations that persisted over 1 year despite greater medication requirements. Obese children also had minimal clinical improvement in asthma control and lung function after intramuscular triamcinolone. Leptin, C-reactive protein, and amino acid metabolites associated with glutathione synthesis and oxidative stress differed in obese children. Within the obese group, lower concentrations of arginine-related metabolites also distinguished uncontrolled from controlled asthma at 12 months.

CONCLUSION

Obesity is associated with poorer asthma outcomes and unique systemic inflammatory features that may not be adequately modified with conventional asthma therapies. Novel approaches may be needed given increased symptoms and unique inflammation and oxidative stress in obese children with asthma.

Effects of obesity on pulmonary function considering the transition from obstructive to restrictive pattern from childhood to young adulthood

Adults with obesity exhibit a restrictive pattern, whereas children with obesity exhibit an obstructive pattern. However, the transition process remains unclear. We performed a systematic search for studies reporting on body mass index and pulmonary function in children. The main outcomes were forced expiratory volume in 1 s (FEV₁ ), forced vital capacity (FVC), and their ratio (FEV₁ /FVC). We compared individuals with overweight or with obesity with individuals with normal weight. Random-effects models were used to calculate pooled estimates. A total of 17 studies were included. Individuals with obesity had a lower FEV₁ /FVC ratio (mean difference [MD] = -3.61%; 95% confidence interval [CI] = -4.58%, -2.64%) and a higher percent-predicted FVC (MD = 3.33%; 95% CI = 0.79%, 5.88%) than those with normal weight. Obesity impaired pulmonary function in the obstructive pattern during childhood to young adulthood, and the maximum obstruction was observed at the age of 16 years in boys and 20 years in girls. The effects attenuated at approximately 30 years and then shifted to the restrictive pattern after 35 years of age in men and 40 years in women. The effects of obesity on pulmonary function change from the obstructive pattern in childhood to the restrictive pattern in adulthood.

Adiponectin and Asthma: Knowns, Unknowns and Controversies

Adiponectin is an adipokine associated with the healthy obese phenotype. Adiponectin increases insulin sensitivity and has cardio and vascular protection actions. Studies related to adiponectin, a modulator of the innate and acquired immunity response, have suggested a role of this molecule in asthma. Studies based on various asthma animal models and on the key cells involved in the allergic response have provided important insights about this relation. Some of them indicated protection and others reversed the balance towards negative effects. Many of them described the cellular pathways activated by adiponectin, which are potentially beneficial for asthma prevention or for reduction in the risk of exacerbations. However, conclusive proofs about their efficiency still need to be provided. In this article, we will, briefly, present the general actions of adiponectin and the epidemiological studies supporting the relation with asthma. The main focus of the current review is on the mechanisms of adiponectin and the impact on the pathobiology of asthma. From this perspective, we will provide arguments for and against the positive influence of this molecule in asthma, also indicating the controversies and sketching out the potential directions of research to complete the picture.

The pathophysiological role of adipokines in the development of bronchial asthma combined with obesity

The combined course of bronchial asthma (BA) and obesity is one of the urgent medical and social problems that requires a comprehensive and careful study in connection with a decrease in the quality of life of such patients, an increase in the frequency, duration of hospitalization and a high economic burden for the state as a whole. The relationship between BA and obesity is now confirmed by numerous studies, at the same time, despite the variability of the proposed mechanisms of pathogenetic effects of obesity on asthma, metabolic aspects of the relationship of these diseases need further study. Adipose tissue hormones are responsible for the energy homeostasis of the body therefore, excessive accumulation of adipose tissue is accompanied by the development of an imbalance in metabolic processes in various organs and tissues. Due to the emergence of new scientific data on the role and function of adipokines in the body, metabolic effects of adipokines are considered in the focus of their pathophysiological association with obesity and asthma. This literary review highlights the current understanding of the role of metabolic effects of the most studied adipokines (resistin, retinol-binding protein, leptin and adiponectin) in the development of obesity and BA. Gender and age-dependent features of adipokine levels in BA and obesity are described. Data on the confirmed role of adiponectin and leptin in the progression of BA combined with obesity are presented. It has been shown that the role of resistin and retinol-binding protein in the development of BA combined with obesity has not been studied. It is demonstrated that further study of metabolic activity of adipokines in BA is an actual and perspective direction of researches which will allow to develop new diagnostic and therapeutic strategies in patients with BA with obesity.

Association between obesity and lung function changes by sex and age in adults with asthma

OBJECTIVE

The lung function changes presenting before and after asthma treatment in obese people remain largely unknown. This study aimed to investigate the association between obesity and lung function changes before and after treatment in adults with asthma.

METHODS

We enrolled 937 newly diagnosed asthma patients from Cohort for Reality and Evolution of Adult Asthma in Korea cohort in 2015-2017, who performed follow-up spirometry after three months of asthma treatment. The percentage changes (Δ) between the spirometry results before and after treatment were calculated. Patients were categorized into four body mass index (BMI) groups; underweight (<18.5), normal (18.5-22.9), overweight (23.0-24.9), and obese (≥25.0). Association between percent change of pulmonary function and BMI was analyzed according to sex and/or age (< 45 yrs, 45-65 yrs, ≥ 65 yrs), which were statistically corrected for age, sex, smoking status, and medication history.

RESULTS

There was no consistent correlation between BMI and each lung function parameter. However, there were significant differences between BMI and ΔFEV₁/FVC before and after 3 months of controller treatment. The obese asthmatics showed significantly lower ΔFEV₁/FVC (6.0 ± 13.5%) than the underweight (12.6 ± 21.4%, P = 0.044) or normal weight (9.1 ± 14.6%, P = 0.031). Middle-aged women had higher BMI (24.11 ± 3.60 vs. 22.39 ± 3.52) and lower ΔFEV₁/FVC (5.7 ± 11.9% vs. 8.9 ± 14.3%, P = 0.012) than young women.

CONCLUSIONS

Obesity is negatively correlated with the ΔFEV₁/FVC before and after controller treatment. Sex and age differentially contribute to lung function changes in response to asthma medications in adult asthmatics, showing a significant decrease in the ΔFEV₁/FVC in middle-aged women.

Association of obesity with severity outcomes in hospitalized pediatric asthma exacerbations

INTRODUCTION

While there seems to be an association between obesity and asthma, the exact nature of the relationship remains unknown. It is unclear if there is increased severity of exacerbation for those that require hospitalization. We examine the association between obesity and severity outcomes such as hospital length of stay, intensive care admissions, and need for continuous albuterol or magnesium administration.

METHODS

Patients 4 to 17 years old admitted between 1/1/2012-1/1/2016 with asthma identified by discharge codes were reviewed. Obesity was defined as BMI ≥95%. Clinical data such as age, gender, family history of asthma, use of controller medication along with outcome data such as length of stay, ICU admission, use of continuous albuterol, and use of magnesium were collected. Binary outcomes were analyzed with multivariate logistic regression while length of stay was analyzed with negative binomial regression.

RESULTS

Overall, 995 patients met inclusion criteria. The median age was 7 years old with 170 (17%) patients categorized as obese. We find no difference in length of stay (IRR 0.99 [0.91, 1.09], p = 0.9), PICU admission (OR 0.72 [0.43, 1.21], p = 0.22), or magnesium administration (OR 1.34 [0.95, 1.88], p = 0.09) between obese and non-obese patients. There were increased odds of continuous albuterol use (OR 1.47 [1.02, 2.11]) for obese patients.

CONCLUSION

We find no association between obesity and outcomes of length of stay, ICU admission, or magnesium administration. While growing evidence links obesity with asthma, our study suggests it may not be associated with the severity of exacerbation.

Inflammation in Obesity-Related Complications in Children: The Protective Effect of Diet and Its Potential Role as a Therapeutic Agent

Obesity is a growing health problem in both children and adults, impairing physical and mental state and impacting health care system costs in both developed and developing countries. It is well-known that individuals with excessive weight gain frequently develop obesity-related complications, which are mainly known as Non-Communicable Diseases (NCDs), including cardiovascular disease, type 2 diabetes mellitus, metabolic syndrome, non-alcoholic fatty liver disease, hypertension, hyperlipidemia and many other risk factors proven to be associated with chronic inflammation, causing disability and reduced life expectancy. This review aims to present and discuss complications related to inflammation in pediatric obesity, the critical role of nutrition and diet in obesity-comorbidity prevention and treatment, and the impact of lifestyle. Appropriate early dietary intervention for the management of pediatric overweight and obesity is recommended for overall healthy growth and prevention of comorbidities in adulthood.

How to apply the personalized medicine in obesity-associated asthma?

INTRODUCTION

Obesity-associated asthma (OA) is frequently severe, with an increased rate of hospitalizations, numerous comorbidities and low response to corticosteroids. Despite progress in applying for personalized medicine in asthma, no specific recommendations exist for the management of OA.

AREAS COVERED

The aim of this review is to summarize recent data about the relationship obesity-asthma, describe clinical characteristics, potential mechanisms involved and possible therapeutic interventions to improve OA outcomes. Extensive research in the PubMed was performed using the following terms: "asthma and obesity" and "obese asthma" in combination with "phenotypes", "airway inflammation", "biomarkers", "lung function", "weight loss", "lifestyle interventions", "therapies" Currently two phenotypes are described. Early-onset atopic asthma is conventional allergic asthma aggravated by the pro-inflammatory properties of adipose tissue in excess, while late-onset non-atopic asthma is due to airway dysfunction as a consequence of the chronic lung compression caused by the obese chest walls. Previous data showed that different therapeutic strategies used in weight loss have a positive impact on OA outcomes.

EXPERT OPINION

The presence of a multidisciplinary team (chest physician, nutritionist, exercise physiologist, physiotherapist, psychologist, bariatric surgeon) and the collaboration between different specialists are mandatory to optimize the management and to apply the personalized medicine in OA.

Adipokines in adolescence; the associations with lung function and atopy - A cross-sectional study

Both inflammatory and mechanical effects have been proposed to explain the increased risk of asthma and reduced lung function observed in obese children and adults. The evidence regarding the potential role of obesity in the aetiology of atopy and allergy is more conflicting. The adipokines leptin and adiponectin are inflammatory markers of fat metabolism which may be involved in explaining the increased risk of asthma and reduced lung function in obese children and adults. In this cross-sectional study, we aimed to study how adiponectin and leptin were associated with lung function and atopic sensitisation in adolescents. The study included 384 children at mean age 12.9 years with measurements of adiponectin, leptin, lung function and atopic sensitisation. Adiponectin and leptin levels were measured in serum, lung function was measured by spirometry and atopic sensitisation was measured by serum specific Immunoglobulin E. In linear regression models, leptin was negatively associated with forced vital capacity (FVC) (Beta: -4.13; 95% Confidence Interval: -5.83, -2.44, P < 0.001) and forced expiratory volume in the first second (FEV₁) (-3.74; -5.39, -2.09, P < 0.001) after adjusting for body mass index (BMI) and other covariates. No associations were observed between adiponectin and lung function or between leptin or adiponectin and atopic sensitisation. In this cross-sectional analysis of adolescents in all weight classes, leptin was negatively associated with FEV₁ and FVC independent of BMI, but no associations were found between adiponectin and lung function. The results suggest that leptin may have a functional role in the airways of healthy children.

Obesity and childhood asthma

PURPOSE OF REVIEW

Asthma is a common chronic disease of the airways characterized by recurrent respiratory symptoms, bronchoreactivity, and airway inflammation. The high toll on quality of life has led to sustained efforts to understand the factors leading to asthma inception and poor disease control. Obesity is another increasingly common pediatric disease, which appears to increase the risk for incident asthma and worsened disease severity. Currently, our understanding of how obesity affects asthma risk and affects its phenotypic characteristics remains incomplete. The current review describes our current understanding of the epidemiology, clinical characteristics, and management considerations of obesity-related asthma in children.

RECENT FINDINGS

The epidemiologic relationship between obesity in children and incident asthma remains confusing despite numerous longitudinal cohort studies, and appears to be influenced by early life exposures, patterns of somatic growth and underlying familial risks of allergic disease. Children with comorbid obesity and asthma demonstrate diverse phenotypic characteristics which are still becoming clear.

SUMMARY

Like any child with asthma, a child with comorbid obesity requires an individualized approach adhering to current best-practice guidelines and an understanding of how obesity and asthma may interact.

Obesity Does Not Increase the Risk of Asthma Readmissions

The relationship between obesity and asthma exacerbations is still under debate. The aim of our work is to analyse the relationship between obesity and hospital re-admissions in asthmatics. A review was retrospectively performed on all hospital admissions of adult patients due to asthma exacerbation occurring in our hospital for 11 years. All those cases with asthma as the first diagnosis in the discharge report were included, or those with asthma as the second diagnosis provided when the first diagnosis was respiratory infection or respiratory failure. Only the first hospital admission of each patient was included in this study. The Odds Ratios of a higher incidence of early/late readmissions due to asthma exacerbation were calculated using a binary logistic regression, using the body mass index (BMI) as independent variable, adjusted for all the variables included in the study. The study included 809 patients with a mean age of 55.6 years, and 65.2% were female. The majority (71.4%) were obese or overweight. No significant relationship was observed in the univariate or multivariate analyses between overweight or obesity and the early or late hospital readmissions due to asthma. Therefore, obesity does not seem to be a determining factor in the risk of asthma exacerbations.

[Asthma and obesity in adults]

Asthma is a chronic inflammatory airway disorder characterized by a multitude of phenotypes. Epidemiological studies show an increase in asthma prevalence in obese patients regardless of age. The association of asthma and obesity is now considered as a phenotype with its own clinical, biological and functional characteristics. Regarding the pathophysiology of asthma and obesity, numerous factors such as nutrition, genetic predisposition, microbiome, ventilatory mechanics and the role of adipose tissue have been identified to explain the heterogeneous characteristics of patients with asthma and obesity. In adult patients with asthma and obesity, respiratory symptoms are particularly prominent and atopy and eosinophilic inflammation is uncommon compared to normal weight asthma patients. Obese asthma patients experience more hospitalizations and use more rescue medications than normal weight asthmatics. Management of asthma in obese patients is complex because these patients have less response to the usual anti-asthmatic treatments. Weight loss through caloric restriction combined with exercise is the main intervention to obtain improvement of asthma outcomes. Bariatric surgery is an invasive procedure with interesting results.

Nutrient intake is a predictor of lung function in obese asthmatic adolescents undergoing interdisciplinary therapy

Asthma-obesity is a multifactorial disease with specific asthma phenotypes that aggravate due to overweight and an unbalanced diet. Furthermore, obese asthmatic patients are corticotherapy-resistant. Therefore, the aims of the present study were to evaluate the effects of an interdisciplinary intervention on food consumption, body composition, lung function and adipokines in asthmatic and non-asthmatic obese adolescents and to investigate the influence of nutrients on lung function. Obese non-asthmatic (n 42) and obese asthmatic (n 21) adolescents of both sexes were enrolled in the present study. Food intake, adipokine levels, body composition, asthma symptoms and lung function were assessed across the study. After the intervention of 1 year, there was a reduction (P ≤ 0·01) in BMI, body fat percentage, visceral and subcutaneous fat and an increase (P ≤ 0·01) in lean mass and all lung function variables in both groups, except the relation between forced expiratory volume in 1 s and forced vital capacity (FEV1:FVC) in non-asthmatic patients. Moreover, both groups decreased lipid and cholesterol consumption (P ≤ 0·01). The highest energy consumption (β = -0·021) was associated with lower values of FVC. Similarly, carbohydrate consumption (β = -0·06) and cholesterol were negative predictors (β = -0·05) in FEV1:FVC. However, the consumption of Ca (β = 0·01), fibres (β = 1·34) and vitamin A (β = 0·01) were positive predictors of FEV1:FVC. Asthma-obesity interdisciplinary treatment promoted an improvement on food consumption and lung function in adolescents and demonstrated that the consumption of nutrients influenced an increase in lung function.

Obesity-Related Asthma: Immune Regulation and Potential Targeted Therapies

Obesity, one of the most severe public health problems of the 21st century, is a common metabolic syndrome due to excess body fat. The incidence and severity of obesity-related asthma have undergone a dramatic increase. Because obesity-related asthma is poorly controlled using conventional therapies, alternative and complementary therapies are urgently needed. Lipid metabolism may be abnormal in obesity-related asthma, and immune modulation therapies need to be investigated. Herein, we describe the immune regulators of lipid metabolism in obesity as well as the interplay of obesity and asthma. These lay the foundations for targeted therapies in terms of direct and indirect immune regulators of lipid metabolism, which ultimately help provide effective control of obesity-related asthma with a feasible treatment strategy.

Fighting obesity: Non-pharmacological interventions

The abnormal or excessive fat accumulation that impairs health is one of the criteria that fulfills obesity. According to epidemiological data, obesity has become a worldwide public health problem that in turn would trigger additional pathologies such as cardiorespiratory dysfunctions, cancer, gastrointestinal disturbances, depression, sleep disorders, just to mention a few. Then, the search for a therapeutical intervention aimed to prevent and manage obesity has been the focus of study during the last years. As one can assume, the increased prevalence of obesity has translated to search of efficient pharmaceuticals designed to manage this health issue. However, to further complicate the scenario, scientific literature has described that obesity is the result of interaction between multiple events. Therefore, pharmacological approaches have faced a serious challenge for develop the adequate treatment. Here, we argue that a wide range of non-pharmacological/invasive techniques can be used to manage obesity, such as diets, cognitive behavioral interventions, exercise and transcranial direct current stimulation. Combining these techniques may allow improving quality of life of obese patients.

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.