Obesity and asthma

Association between a western diet and asthma among children and adolescents

Several risk factors including environmental exposures, socioeconomic status, and dietary factors including dietary patterns have been considered for childhood Asthma. The present study tried to examine the association between a western-style pattern and the likelihood of asthma and its symptoms in Yazd, Iran. In the present cross-sectional study, dietary intakes of elementary and high-school children were obtained through a validated GAN questionnaire. The GAN questionnaire, derived from the ISAAC questionnaire was used to assess the symptoms of allergic diseases and their related risk factors. A western dietary pattern score considered 9 food groups including chicken eggs, margarine, butter, sugar, fast foods, soft drinks, snacks, sauce, and chocolate. In total 7667 children aged 10.9 ± 3.35 years were included in the current investigation. Boys with higher adherence to western dietary pattern had a higher risk of wheezing in the past 12 months (OR 1.37, 5% CI 1.01-1.87, P = 0.04) and this association was also observed in the whole population (OR 1.30, 5% CI 1.05-1.60, P = 0.01). However, after adjustment for confounders this relation did not remain significant in boys. Our results support the hypothesis that a western dietary pattern is associated with an increased risk of wheezing in the past 12 months in children with asthma. Future prospective studies are needed to confirm this finding.

Free fatty acid receptor 4 (FFA4) activation attenuates obese asthma by suppressing adiposity and resolving metaflammation

Obese asthma is recognized to have different asthma phenotypes. N-3 polyunsaturated fatty acids (PUFAs) have shown beneficial effects in obesity and metabolic syndrome. Free fatty acid receptor 4 (FFA4, also known as GPR120) is a receptor for n-3 PUFAs. In the present study, we investigated whether FFA4 activation ameliorates high-fat diet (HFD)-induced obese asthma. We investigated whether FFA4 activation ameliorates obese asthma using an FFA4 agonist, compound A (CpdA), in combination with FFA4 wild-type (WT) and knock-out (KO) mice. Administration of an FFA4 agonist, compound A (CpdA, 30 mg/kg), suppressed HFD-induced weight gain, adiposity, and airway hypersensitivity (AHR), and increased immune cell infiltration in an FFA4-dependent manner. Histological analysis revealed that CpdA treatment suppressed HFD-induced mucus hypersecretion, inflammation, and fibrosis in an FFA4-dependent manner. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) showed an HFD-induced increase in the mRNA levels of pro-inflammatory cytokines in the lungs and gonadal white adipose tissue, whereas CpdA inhibited this increase in an FFA4-dependent manner. In the fluorescence-activated cell sorting (FACS) analysis, HFD induced an increase in the lung innate lymphoid cells (ILC) ILC1, ILC2, and ILC3; however, CpdA reversed this increase. In addition, HFD induced an increase in the pro-inflammatory M1 macrophage population and a decrease in the anti-inflammatory M2 macrophage population in the lungs, whereas CpdA treatment reversed these changes. The present study suggests that FFA4 activation may have therapeutic potential in obese asthma.

Characterization of Obesity in Severe Asthma in the German Asthma Net

BACKGROUND

Asthma is increasingly recognized as heterogeneous, characterized by different endotypes, with obesity not only a distinct phenotype but a risk factor for severe asthma.

OBJECTIVE

We sought to understand the associations of obesity with relevant parameters of severe asthma, including asthma control, disease burden, and lung function.

METHODS

The German Asthma Net registry is a multicenter international real-life registry capturing long-term follow-up data. This analysis included 2213 patients (52 ± 16 years, 58% female, 29% with obesity [body mass index ≥30 kg/m2], 4.2 ± 4.3 exacerbations/year). The primary analysis assessed relationships between BMI and variables through univariate tests, followed by a multiple regression model. Secondary outcomes regarded clinically relevant variables in relation to weight groups.

RESULTS

Patients with obesity were more frequently female, more likely to have depression and gastroesophageal reflux, and suffered from worse asthma control, lower quality of life, reduced static lung volumes, more pronounced hypoxemia, and higher blood neutrophil counts, all statistically significant. Blood eosinophils, exhaled nitric oxide, and total IgE were independent of obesity. In the multiple regression analysis, obesity was significantly associated with more frequent reflux and depression, reduced static lung function values, older age, poor asthma control, and long-acting muscarinic antagonist therapy, and inversely associated with bronchiectasis and nonsmoking status.

CONCLUSION

In this large, well-characterized cohort, we identified the association of obesity with a significantly higher disease burden and a similar portfolio of inflammation type 2 markers in patients with and without obesity; therefore, patients with obesity seem similarly eligible for the treatment with biologics targeting these disease endotypes.

Leptin and Asthma: What Are the Interactive Correlations?

Leptin is an adipokine directly correlated with the proinflammatory obese-associated phenotype. Leptin has been demonstrated to inhibit adipogenesis, promote fat demarcation, promote a chronic inflammatory state, increase insulin sensitivity, and promote angiogenesis. Leptin, a regulator of the immune response, is implicated in the pathology of asthma. Studies involved in the key cell reaction and animal models of asthma have provided vital insights into the proinflammatory role of leptin in asthma. Many studies described the immune cell and related cellular pathways activated by leptin, which are beneficial in asthma development and increasing exacerbations. Subsequent studies relating to animal models support the role of leptin in increasing inflammatory cell infiltration, airway hyperresponsiveness, and inflammatory responses. However, the conclusive effects of leptin in asthma are not well elaborated. In the present study, we explored the general functions and the clinical cohort study supporting the association between leptin and asthma. The main objective of our review is to address the knowns and unknowns of leptin on asthma. In this perspective, the arguments about the different faces of leptin in asthma are provided to picture the potential directions, thus yielding a better understanding of asthma development.

Maternal BMI and allergy in children until 3 years of age (JECS)

Background

Maternal prepregnancy body mass index (BMI) may influence allergic diseases in the children who are the product of those pregnancies.

Objective

The purpose of our study was to investigate the association between mothers' prepregnancy BMI and the risk of physician-diagnosed asthma, food allergy (FA), and atopic dermatitis (AD) in their children during the first 3 years of life.

Methods

Data on mothers' prepregnancy BMI and physician-diagnosed asthma, FA, and AD in their children until the age of 3 years were obtained from the Japan Environment and Children's Study, a nationwide birth cohort study that has recruited 103,099 pregnant women between 2011 and 2014. Logistic regression analysis was used to analyze the results.

Results

We analyzed 67,204 mother-child pairs with available information on physician-diagnosed allergic diseases. The risk of asthma was significantly higher in children born to overweight mothers (adjusted OR [aOR] =1.17 [95% CI = 1.07-1.28]) and obese mothers (aOR = 1.28 [95% CI = 1.08-1.50]), whereas the risk of FA, cow's milk allergy, and egg allergy decreased significantly in children born to overweight mothers (aOR = 0.84 [95% CI = 0.76-0.92]; aOR = 0.78 [95% CI = 0.64-0.93]; and aOR = 0.83 [95% CI = 0.74-0.94]) and obese mothers (aOR = 0.81 [95% CI = 0.67-0.97]; aOR = 0.58 [95% CI = 0.36-0.87]; and aOR = 0.73 [95% CI = 0.56-0.93]) compared with in children born to normal weight mothers, respectively. Associations between AD and maternal BMI were not detected.

Conclusion

Our study showed that an increase in mothers' prepregnancy BMI was associated with an increase in asthma prevalence and a decrease in FA prevalence in their children. Further studies are needed to reveal the mechanisms associated with maternal BMI and pediatric allergic diseases.

Helminth and Host Crosstalk: New Insight Into Treatment of Obesity and Its Associated Metabolic Syndromes

Obesity and its associated Metabolic Syndromes (Mets) represent a global epidemic health problem. Metabolic inflammation, lipid accumulation and insulin resistance contribute to the progression of these diseases, thereby becoming targets for drug development. Epidemiological data have showed that the rate of helminth infection negatively correlates with the incidence of obesity and Mets. Correspondingly, numerous animal experiments and a few of clinic trials in human demonstrate that helminth infection or its derived molecules can mitigate obesity and Mets via induction of macrophage M2 polarization, inhibition of adipogenesis, promotion of fat browning, and improvement of glucose tolerance, insulin resistance and metabolic inflammation. Interestingly, sporadic studies also uncover that several helminth infections can reshape gut microbiota of hosts, which is intimately implicated in the pathogenesis of obesity and Mets. Overall, these findings indicate that the crosstalk between helminth and hosts may be a novel direction for obesity and Mets therapy. The present article reviews the molecular mechanism of how helminth masters immunity and metabolism in obesity.

A nationwide survey of the association between nonalcoholic fatty liver disease and the incidence of asthma in Korean adults

Background

Asthma and nonalcoholic fatty liver disease (NAFLD) are chronic diseases known to be associated with metabolic abnormalities. We aimed to clarify the association between NAFLD and asthma incidence in a large population-based cohort.

Methods and findings

We selected 160,603 individuals without comorbidities from the National Health Insurance Service-National Sample cohort between 2009 and 2014. NAFLD was defined using a surrogate marker, fatty liver index (FLI). During a median of 5.08 years’ follow-up, 16,377 subjects (10.2%) were newly diagnosed with asthma and categorized into three groups according to FLI. The cumulative incidence of asthma was higher in subjects with higher vs. lower FLIs (FLI < 30, 10.1%; 30 ≤ FLI < 60, 10.8%; FLI ≥ 60, 10.5%). Higher FLI was associated with an increased incidence of asthma (Hazard ratios (HR)_{highest vs. lowest FLI}, 1.25; 95% CI, 1.15–1.36). The results using another definition of NAFLD, as measured by the hepatic steatosis index (HSI), were similar to the primary results. This association was more pronounced in women than in men (HR 1.46; 95% CI, 1.13–1.64 vs. HR 1.07; 95% CI, 0.94–1.20).

Conclusions

This study demonstrated that NAFLD, as measured by FLI and HSI, may influence the incidence rates of asthma in adults, especially in women.

Parental experiences of adopting healthy lifestyles for children with disabilities living with overweight and obesity

BACKGROUND

Children with disabilities present with high obesity rates.

OBJECTIVE

This study explored the parental experience of adopting healthy lifestyle choices, for children with disabilities, who received dietetic weight management advice.

METHODS

Semi-structured qualitative interviews were carried out with eight parents/carers in their own homes or healthcare setting in an inner London locality, or by telephone. Data was analyzed using an interpretative phenomenological analysis (IPA) approach.

RESULTS

Five superordinate themes emerged: 1. Strategies to promote healthy lifestyles: encouraging physical activity, limiting access to food and taking a gradual approach to making lifestyle changes. 2. Challenges to adopting healthy lifestyles: selective eating patterns, the high cost of healthy foods and parental/carer lack of time. 3. The role of healthcare professionals (HCPs): revealed that not all parents/carers received advice or support, prior to dietetic referral, when managing their child's weight. Feeling reassured by HCPs was valued. Parents/carers reported a positive experience of seeing the dietitian, as they appreciated receiving practical and individualized advice. 4. Support needs: family support and support from families with children with disabilities was explored. 5. Parent/carer wellbeing: such as stress was found to have a detrimental impact on parents making healthy lifestyle changes.

CONCLUSIONS

Adopting a healthy lifestyle involved a variety of strategies and challenges, some of which are specific to this population group and should be considered by HCPs, when having weight-related discussions and offering advice. Parental/carer support needs and wellbeing should also be taken into consideration when planning weight management services for this population group.

Asthma, Allergic Rhinitis, and Atopic Dermatitis Incidence in Korean Adolescents before and after COVID-19

With changes in personal habits (masks and handwashing) during the COVID-19 outbreak, the study analyzed the reporting of physician-diagnosed cases (incidence) of allergic diseases (asthma, allergic rhinitis, and atopic dermatitis) using the data for years 2019 and 2020 from the Korean adolescent risk behavior web-based survey (KYRBWS-15 and 16). Altogether, 92,659 adolescents (48,443 in 2019 and 44,216 in 2020) were enrolled. The crude and adjusted odd ratios (ORs) were calculated for each disease in 2020 compared to that in 2019 using multiple logistic regression. Subgroup analyses were performed according to sex and economic status. The incidence of asthma decreased from 1.5% in 2019 to 1.0% 2020 (p < 0.001). The incidence of allergic rhinitis in 2019 and 2020 was 19.5% and 16.3%, respectively (p < 0.001). Compared with 2019, the adjusted OR (aOR) in 2020 was 0.68 (95% CI = 0.66–0.77, p value < 0.001) for asthma and 0.82 (95% CI = 0.78–0.85, p < 0.001) for allergic rhinitis. In contrast, there was no statistically significant difference between the incidence of atopic dermatitis in 2019 and that in 2020 (6.4%, vs. 6.4%, p > 0.05, respectively). Subgroup analyses results were consistent. In conclusion, there was decrease in the incidence of asthma and allergic rhinitis but not in that of atopic dermatitis from 2019 to 2020.

[Obstructive sleep apnea and asthma: Clinical implications]

Obstructive sleep apnea (OSA) and asthma are common respiratory diseases that can coexist in the same patient. Epidemiological and pathophysiological data suggest an independent link between these two diseases. Specially, OSA is frequently associated with non-eosinophilic and with poorly-controlled asthma. Common comorbidities including obesity, gastroesophageal reflux and rhinitis may promote this association. The impact of OSA treatment on the clinical and functional control of asthma has been extensively investigated. Numerous non-randomized studies suggest that continuous positive pressure treatment is likely to improve asthma symptoms, the control of the disease and quality of life in asthmatics with OSA. However, this impact has not been confirmed in the limited randomized trial available. To date, the optimal treatment approach in asthmatics with OSA is the best treatment of each disease separately and the recognition and treatment of comorbidities. When indicated, obesity surgery has a major impact on both diseases.

Linggan Wuwei Jiangxin formula ameliorates airway hyperresponsiveness through suppression of IL-1β and IL-17A expression in allergic asthmatic mice especially with diet-induced obesity

Background

Obese asthma represents a disease phenotype, which is associated with worse disease control and unresponsiveness to standard anti-inflammatory regimens, including inhaled corticosteroids. Obesity-related innate airway hyperresponsiveness (AHR) plays a role in this asthma phenotype via activation of the IL-1β/innate lymphoid cell 3 (ILC3)/IL-17A pathway. Linggan Wuwei Jiangxin (LGWWJX) formula may be a promising therapeutic option for obese asthma according to traditional Chinese medicine theory, clinical experience and related research.

Methods

The murine model of allergic asthma with obesity was induced by ovalbumin (OVA) sensitization and challenge in combination with a high fat diet (HFD). LGWWJX formula intervention was oral administrated. AHR and bronchoalveolar lavage fluid (BALF) cellularity were measured. Lung and liver histopathology assessment was performed by haematoxylin and eosin (H&E) staining. IL-1β and IL-17A in BALF and serum were evaluated by ELISA. Additionally, the influence of different concentrations of LGWWJX formula on IL-1β stimulated IL-17A mRNA expression in ILC3 cells was evaluated in vitro.

Results

LGWWJX treatment significantly reduced AHR and allergic airway inflammatory responses in asthmatic mice, as measured by pulmonary histopathology and BALF cellularity, and these effects were more pronounced in obese asthmatic mice. While eosinophil infiltration in BALF was suppressed with LGWWJX treatment in non-obese asthmatic mice, neutrophils and basophils were significantly decreased in obese asthmatic mice. Notably, LGWWJX also demonstrated remarkable efficacy for weight loss and improvements in hepatic steatosis in mice fed with a HFD. Furthermore, the protein levels of IL-1β in both serum and BALF, as well as those of BALF IL-17A, declined with LGWWJX intervention in both obese and non-obese asthmatic mice, and results from ex-vivo experiments found that LGWWJX significantly attenuated the expression of IL-17A in ILC3 cells with or without stimulation by IL-1β.

Conclusions

LGWWJX may exert a protective effect on asthmatic individuals, especially those with concurrent obesity, most likely through mechanisms including the inhibition of the IL-1β/ILC3/IL-17A/AHR axis, anti-inflammatory effects, weight loss, and the regulation of lipid metabolism. This suggests a promising role of LGWWJX, alone or in combination with anti-inflammatory agents, for the treatment of obese asthma.

Fatty acid-binding protein 5 limits ILC2-mediated allergic lung inflammation in a murine asthma model

Dietary obesity is regarded as a problem worldwide, and it has been revealed the strong linkage between obesity and allergic inflammation. Fatty acid-binding protein 5 (FABP5) is expressed in lung cells, such as alveolar epithelial cells (ECs) and alveolar macrophages, and plays an important role in infectious lung inflammation. However, we do not know precise mechanisms on how lipid metabolic change in the lung affects allergic lung inflammation. In this study, we showed that Fabp5^−/− mice exhibited a severe symptom of allergic lung inflammation. We sought to examine the role of FABP5 in the allergic lung inflammation and demonstrated that the expression of FABP5 acts as a novel positive regulator of ST2 expression in alveolar ECs to generate retinoic acid (RA) and supports the synthesis of RA from type II alveolar ECs to suppress excessive activation of innate lymphoid cell (ILC) 2 during allergic lung inflammation. Furthermore, high-fat diet (HFD)-fed mice exhibit the downregulation of FABP5 and ST2 expression in the lung tissue compared with normal diet (ND)-fed mice. These phenomena might be the reason why obese people are more susceptible to allergic lung inflammation. Thus, FABP5 is potentially a therapeutic target for treating ILC2-mediated allergic lung inflammation.

Asthma and Obstructive Sleep Apnea Overlap: What Has the Evidence Taught Us?

Obstructive sleep apnea (OSA) and asthma are highly prevalent chronic respiratory disorders. Beyond their frequent coexistence arising from their high prevalence and shared risk factors, these disorders feature a reciprocal interaction whereby each disease impacts the severity of the other. Emerging evidence implicates airway and systemic inflammation, neuroimmune interactions, and effects of asthma-controlling medications (corticosteroids) as factors that predispose patients with asthma to OSA. Conversely, undiagnosed or inadequately treated OSA adversely affects asthma control, partly via effects of intermittent hypoxia on airway inflammation and tissue remodeling. In this article, we review multiple lines of recently published evidence supporting this interaction. We provide a set of recommendations for clinicians involved in the care of adults with asthma, and identify critical gaps in our knowledge about this overlap.

The Nonantibiotic Macrolide EM900 Attenuates House Dust Mite-Induced Airway Inflammation in a Mouse Model of Obesity-Associated Asthma

INTRODUCTION

Obesity-associated asthma is characterized by type 2-low airway inflammation. We previously showed that EM900, which is a 12-membered nonantibiotic macrolide, suppressed airway inflammation in a mouse model of asthma exacerbation. The aim of this study was to clarify the effects of EM900 in obesity-associated asthma.

METHODS

BALB/c mice were fed a low-fat diet (LFD) or high-fat diet (HFD). Mice were intranasally sensitized and challenged with house dust mites (HDMs) and were orally administered EM900. Airway inflammation was assessed using inflammatory cells in bronchoalveolar lavage (BALF). Cytokines were examined by ELISA in lung tissues. Lung interstitial macrophages (CD45+, CD11clow, CD11b+, and Ly6c-) were counted by flow cytometry in single cells from lung tissues.

RESULTS

Body weight increased significantly in the HFD compared with the LFD group. The total cell count and numbers of neutrophils and eosinophils in BALF were significantly suppressed by EM900 administration in the HFD-HDM group. The levels of interleukin (IL)-17A were increased in the HFD-HDM group compared with the LFD-HDM group, although the difference did not reach statistical significance. The levels of IL-17A, macrophage inflammatory protein 2, IL-1β, IL-5, and regulated on activation, normal T cell expressed and secreted in lung tissue were significantly suppressed by EM900 administration in the HFD-HDM group. The percentage of interstitial macrophages in lungs was significantly decreased by EM900 administration in the HFD-HDM group.

CONCLUSION

Both type 2 and type 2-low airway inflammation were attenuated by EM900 in this obesity-associated asthma model. These results show that EM900 might be a candidate agent for the treatment of obesity-associated asthma.

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.

Systemic Inflammation Mediates the Associations Between Abdominal Obesity Indices and Lung Function Decline in a Chinese General Population

BACKGROUND

Previous studies reported that obesity indices were inversely associated with lung function. However, the underlying mechanisms remain unclear. We aimed to assess the potential mediating effect of systemic inflammation in the associations between obesity indices and lung function decline among a general population.

METHODS

We conducted a cross-sectional study among 3442 participants from the Wuhan-Zhuhai cohort. Plasma C-reactive protein (CRP) was assayed as a marker of systemic inflammation. The relationships among several obesity indices (body mass index, BMI; waist circumference, WC; waist-to-hip ratio, WHR; waist-to-height ratio, WHtR), plasma CRP and lung function were assessed by generalized linear models. The role of CRP in the associations between obesity indices and lung function was analyzed using mediation analysis.

RESULTS

We observed inverse associations between abdominal obesity indices (WC, WHR and WHtR) and lung function parameters, including forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) (all P<0.05). Each 1-unit increase in WC was associated with a 3.39 mL decrease in FEV₁ and a 3.96 mL decrease in FVC (all P<0.05). Each 1% increase in WHR and WHtR was associated with a 5.42 mL and a 14.23 mL decrease in FEV₁, and a 5.70 mL and a 16.92 mL decrease in FVC (all P<0.05). Mediation analysis indicated that plasma CRP partly mediated the associations between abdominal obesity and lung function. The mediated proportions of CRP in associations of WC, WHR and WHtR with FEV₁ were 7.96%, 9.59% and 5.76%, respectively. The mediated proportions of CRP in associations of WC and WHR with FVC were 8.33% and 11.40%, respectively.

CONCLUSION

Abdominal obesity indices were negatively associated with lung function, and the associations may be partly mediated by systemic inflammation.

Obesity-induced asthma: Role of free fatty acid receptors

Obesity is a major risk factor for the development of asthma, and worsens the key features of asthma including airway hyperresponsiveness, inflammation, and airway remodeling. Although pro- and anti-inflammatory adipocytokines may contribute to the pathogenesis of asthma in obesity, the mechanistic basis for the relationship between asthma and obesity remains unclear. In obese individuals, the increased amount of adipose tissue results in the release of more long-chain free fatty acids as compared to lean individuals, causing an elevation in plasma long-chain free fatty acid concentrations. Recent findings suggest that the free fatty acid receptor 1 (FFAR1), which is a sensor of medium- and long-chain free fatty acids, is expressed on airway smooth muscle and plays a pivotal role in airway contraction and airway smooth muscle cell proliferation. In contrast, FFAR4, which is a sensor for long-chain n-3 polyunsaturated fatty acids and also expressed on airway smooth muscle, does not contribute to airway contraction and airway smooth muscle cell proliferation. Functional roles for short-chain fatty acid receptors FFAR2 and FFAR3 in the pathogenesis of asthma is still under debate. Taken together, adipose-derived long-chain free fatty acids may contribute to the pathogenesis of asthma in obesity through FFAR1.

The Association between Asthma and Obesity in Children - Inflammatory and Mechanical Factors

BACKGROUND:

Association of asthma and obesity has been demonstrated in numerous epidemiological studies. However, the underlying mechanisms of the association are not well understood. Both conditions are characterised by chronic tissue inflammation, which includes numerous different inflammatory markers, and possible atopy.

AIM:

The study aimed to investigate the association between asthma and obesity in children and assess several of potential underlying mechanisms, including the parameters of systemic inflammation (CRP, fibrinogen) and the mechanical effect of obesity on the respiratory system through parameters of lung function. An additional aim was to examine the role of atopy in overweight children with asthma and to investigate the type of respiratory inflammation.

MATERIAL AND METHODS:

This prospective study included 72 patients in the age group of 7-15 years, including 38 with high body mass index (BMI), 16 with asthma and normal BMI, and 18 with asthma and high BMI for sex and age. Non-specific inflammatory markers (fibrinogen, CRP), eosinophilia, and total serum IgE were investigated. The patients underwent a skin prick test (SPT) with standard inhalant allergen extracts, measurement of fractional exhaled nitric oxide Fe (NO), and an assessment of lung function.

RESULTS:

In overweight groups of children we determined significantly higher values (p < 0.001) of both acute inflammatory reactants, CRP and fibrinogen, with no difference between children with and without asthma. There was a significant increase in eosinophilia, total IgE, and positive SPT in the asthmatic groups compared to the group of non-asthmatic patients (p < 0.001 for the three parameters). Compared to the group composed of overweight patients without asthma, the asthmatic patients had higher NO values (p < 0.001). No significant difference in the lung function parameters was found between the three groups (p > 0.05).

CONCLUSION:

A positive association between asthma and obesity with inflammation as an underlying mechanism, eosinophilic one in asthmatic patients and non-eosinophilic one in overweight patients, was determined. It seems that the lung function parameters did not differ between asthmatic patients and overweight patients. No influence of atopy in the association between asthma and obesity was verified. Further analyses of specific inflammatory markers, for an in-depth evaluation of the mechanisms leading to the association of obesity and asthma, are warranted.

Effect of high fat diet on NF-кB microRNA146a negative feedback loop in ovalbumin-sensitized rats

The present study aimed to investigate the role of microRNA-146a and its adapter proteins [interleukin-1 receptor-associated kinase 1 (IRAK1) and tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6)] in the pathogenesis of ovalbumin (OVA)-sensitized rats in association with the diet-induced obesity condition. Twenty male Wistar rats were divided into four groups: control with normal diet (ND), OVA-sensitized with normal diet (S + ND), high-fat diet (HFD), and OVA-sensitized with high-fat diet (S + HFD). All the animals were fed for 8 weeks with standard pelts or high-fat diet, and were then sensitized and challenged with OVA or saline for another 4 weeks. The tracheal responsiveness to methacholine, serum protein levels, and lipid profile levels was measured by the ELISA method. Moreover, the gene expression level of microRNA-146a (miR-146a) was measured in the lung tissue of the rats using the real-time PCR method. Maximum response to methacholin increased in the S + HFD group in compared with ND, S + ND, and HFD groups (P < 0.05 to P < 0.001). Moreover, in the S + HFD group the mRNA expression levels of miRNA-146a increased in the lung tissue (P < 0.001). In addition, the protein analysis results showed that IRAK1, TRAF6, NF-kB, and IL-1β protein levels were high in the S + HFD group compared to the ND and HFD groups; however, in compared with the S + ND group, only the IL-1β protein level was higher in the S + HFD group (P < 0.05). These results suggest that a defect in the NF-kB-miR-146a negative feedback loop may be involved in the pathogenesis of obesity associated with OVA-sensitized condition. © 2018 BioFactors, 45(1):75-84, 2019.

Epigallocatechin-3-gallate protects against the exacerbation of allergic eosinophilic inflammation associated with obesity in mice

Obesity is linked to worse asthma symptoms. Epigallocatechin-3-gallate (EGCG) reduces airway inflammation, but no study investigated the effects of EGCG on obesity-associated asthma. We aimed here to evaluate the effects of EGCG on allergen-induced airway inflammation in high-fat diet-fed mice. Male C57Bl/6 mice maintained on either standard-chow or high-fat diet for 12 weeks were treated or not with EGCG (10 mg/kg/day, gavage, two weeks). Animals were intranasally challenged with ovalbumin (OVA). In lung tissue and bronchoalveolar lavage fluid (BALF), cell counting and markers of inflammation and oxidative stress were evaluated. High-fat diet-fed mice exhibited significantly higher body weight and epididymal fat mass compared with lean group. EGCG treatment reduced by 20% the epididymal fat mass in obese mice (P < 0.05). The OVA-induced increases of total cells and eosinophils in lung tissue of obese mice were significantly reduced EGCG treatment. The increased levels of TNF-α, IL-4, IL-5 and eotaxin in BALF of obese mice were normalized by EGCG. Likewise, the enhanced expression of inducible nitric oxide synthase (iNOS) and nitric oxide metabolite (NOx) levels in obese mice were normalized by EGCG. Reactive‑oxygen species (ROS) and superoxide dismutase (SOD) levels were elevated and reduced, respectively, in lung tissue of obese mice, both of which were restored by EGCG. In lean mice, EGCG had no significant effect in evaluated parameter (body measures, and inflammatory and oxidative markers). EGCG turns to normal the levels of inflammatory and oxidative stress markers in lungs of obese mice, suggesting it could be an option to attenuate obesity-related asthma.

High fat diet induces airway hyperresponsiveness in mice

The experiment was conducted to examine the effect of a high fat diet (HFD) on airway hyperresponsiveness (AHR) in mice. Twenty-three adult male C57BL/6 J mice were fed with HFD or regular chow diet for two weeks. The total respiratory resistance was measured by forced oscillation technique at baseline and after methacholine aerosol challenge at 1, 3, 10 and 30 mg/mL. Bronchoalveolar lavage (BAL) was performed. Lipid levels and lipid peroxidation in lung tissue were measured along with gene expression of multiple cytokines. Lungs were digested, and IL-1β secretion by pulmonary macrophages was determined. HFD feeding resulted in 11% higher body weight compared to chow. HFD did not affect respiratory resistance at baseline, but significantly augmented airway responses to methacholine compared to chow diet (40.5 ± 17.7% increase at 30 mg/ml methacholine, p < 0.05). HFD induced a 3.2 ± 0.6 fold increase in IL-1β gene expression (p < 0.001) and a 38 fold increase in IL-1β secretion in the lungs. There was no change in BAL and no change in any other cytokines, lipid levels or lipid peroxidation. Hence, HFD induced AHR in mice prior to the development of significant obesity which was associated with up-regulation of pulmonary IL-1β.

The obese-asthma phenotype in children: An exacerbating situation?

BACKGROUND

Current evidence regarding the relationship between childhood obesity, decreased response to inhaled corticosteroids (ICSs), and poor asthma control is conflicting.

OBJECTIVES

We assessed whether obesity (1) is associated with time to first exacerbation among children with asthma initiating step 3 maintenance therapies and (2) modifies the effectiveness of step 3 therapies.

METHODS

A retrospective cohort study was conducted from clinical data linked to health and drug administrative databases. The cohort consisted of children aged 2 to 18 years with specialist-confirmed asthma who initiated medium/high-dose ICS monotherapy or low/medium-dose ICS with leukotriene receptor antagonist/long-acting β-agonist (combination therapy) at the Montreal Children's Hospital Asthma Center from 2000 to 2007. Children were classified as exposed to step 3 therapies when they were dispensed a corresponding drug claim during follow-up, whereas those without claims were classified as nonadherers. Marginal structural Cox models were used to estimate the effect of obesity (body mass index > 97th percentile) and treatment on time to exacerbation, which was defined as any emergency department visit, hospitalization, or use of oral corticosteroids for asthma.

RESULTS

Of the 4621 cohort patients, 231 initiated ICS monotherapy, and 97 initiated combination therapy. The hazard ratio (HR) for obesity was 1.67 (95% CI, 1.41-1.98). Compared with nonobese nonadherers, the HR for obese nonadherers was 1.54 (95% CI, 0.97-2.45); the HR for ICS monotherapy in obese and nonobese children was 0.85 (95% CI, 0.47-1.52) and 0.58 (95% CI, 0.37-0.91), respectively; and the HR for combination therapy in obese and nonobese children was 0.50 (95% CI, 0.13-1.89) and 0.46 (95% CI, 0.23-0.92), respectively.

CONCLUSION

Obesity might be a determinant of shorter exacerbation-free time in children with asthma; however, we could not rule out a differential response to step 3 therapies by obesity status, potentially because of a lack of precision.

Acute lung injury induced by intestinal ischemia and reperfusion is altered in obese female mice

RATIONAL

Acute lung injury (ALI) is a common complication after intestinal ischemia and reperfusion (I/R) injury that can lead to acute respiratory distress syndrome (ARDS). We have previously demonstrated that females are protected against lung damage induced by intestinal I/R through an estrogen mediated mechanism.

OBJECTIVES

To investigate the effect of obesity on ALI induced by intestinal I/R in female mice.

METHODS

C57Bl/6 female mice were fed with a standard low-fat diet (SD) or a high-fat diet (HFD) for 9 weeks. Intestinal I/R injury was induced by a 45 min occlusion of the mesenteric artery followed by 2 and 24 h of reperfusion.

RESULTS

Significant increase in lung myeloperoxidase expression (MPO) and neutrophil numbers of SD and HFD mice occurred at 2 h and 24 h of reperfusion. Furthermore, HFD mice presented a significant increase in lung eosinophil peroxidase (EPO) expression and eosinophil numbers compared to SD mice. Lung wet/dry weight ratio was significantly greater in HFD mice at 2 and 24 h of reperfusion, accompanied by a significant increase in the expression of inducible NO in the lung tissue and a significant decrease in arterial oxygen saturation at 24 h of reperfusion relative to SD mice.

CONCLUSION

Obesity predisposes female mice to increased pulmonary oedema and deterioration in gas exchange, which is accompanied by an increase in iNOS expression in the lung.

High-fat diet-induced obesity impairs insulin signaling in lungs of allergen-challenged mice: Improvement by resveratrol

Insulin resistance plays an important role in obesity-associated asthma exacerbations. Using a murine model of allergic airway inflammation, we evaluated the insulin signaling transmission in lungs of obese compared with lean mice. We further evaluated the effects of the polyphenol resveratrol in the pulmonary insulin signaling. In lean mice, insulin stimulation significantly increased phosphorylations of AKT, insulin receptor substrate 1 (IRS-1) and insulin receptor β (IRβ) in lung tissue and isolated bronchi (p < 0.05), which were impaired in obese group. Instead, obese mice displayed increased tyrosine nitrations of AKT, IRβ and IRS-1 (p < 0.05). Two-week therapy of obese mice with resveratrol (100 mg/kg/day) restored insulin-stimulated AKT, IRS-1 and IRβ phosphorylations, and simultaneously blunted the tyrosine nitration of these proteins. Additionally, the c-Jun N-terminal kinase (JNK) and inhibitor of NF-κB Kinase (IκK) phosphorylations were significantly increased in obese group, an effect normalized by resveratrol. In separate experiments, the inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine (20 mg/kg/day, three weeks) mimicked the protective effects exerted by resveratrol in lungs of obese mice. Lungs of obese mice display nitrosative-associated impairment of insulin signaling, which is reversed by resveratrol. Polyphenols may be putative drugs to attenuate asthma exacerbations in obese individuals.

The free fatty acid receptor 1 promotes airway smooth muscle cell proliferation through MEK/ERK and PI3K/Akt signaling pathways

Obesity is a risk factor for asthma and influences airway hyperresponsiveness, which is in part modulated by airway smooth muscle proliferative remodeling. Plasma free fatty acids (FFAs) levels are elevated in obese individuals, and long-chain FFAs act as endogenous ligands for the free fatty acid receptor 1 (FFAR1), which couples to both G_q and G_i proteins. We examined whether stimulation of FFAR1 induces airway smooth muscle cell proliferation through classical MEK/ERK and/or phosphoinositide 3-kinase (PI3K)/Akt signaling pathways. The long-chain FFAs (oleic acid and linoleic acid) and a FFAR1 agonist (GW9508) induced human airway smooth muscle (HASM) cell proliferation, which was inhibited by the MEK inhibitor U0126 and the PI3K inhibitor LY294002 . The long-chain FFAs and GW9508 increased phosphorylation of ERK, Akt, and p70S6K in HASM cells and freshly isolated rat airway smooth muscle. Downregulation of FFAR1 in HASM cells by siRNA significantly attenuated oleic acid-induced phosphorylation of ERK and Akt. Oleic acid-induced ERK phosphorylation was blocked by either the Gα_i-protein inhibitor pertussis toxin or U0126 and was partially inhibited by either the Gα_q-specific inhibitor YM-254890 or the Gβγ signaling inhibitor gallein. Oleic acid significantly inhibited forskolin-stimulated cAMP activity, which was attenuated by pertussis toxin. Akt phosphorylation was inhibited by pertussis toxin, the ras inhibitor manumycin A, the Src inhibitor PP1, or LY294002 . Phosphorylation of p70S6K by oleic acid or GW9508 was significantly inhibited by LY294002 , U0126, and the mammalian target of rapamycin (mTOR) inhibitor rapamycin. In conclusion, the FFAR1 promoted airway smooth muscle cell proliferation and p70S6K phosphorylation through MEK/ERK and PI3K/Akt signaling pathways.

Regulation of human airway smooth muscle cell migration and relevance to asthma

Airway remodelling is an important feature of asthma pathogenesis. A key structural change inherent in airway remodelling is increased airway smooth muscle mass. There is emerging evidence to suggest that the migration of airway smooth muscle cells may contribute to cellular hyperplasia, and thus increased airway smooth muscle mass. The precise source of these cells remains unknown. Increased airway smooth muscle mass may be collectively due to airway infiltration of myofibroblasts, neighbouring airway smooth muscle cells in the bundle, or circulating hemopoietic progenitor cells. However, the relative contribution of each cell type is not well understood. In addition, although many studies have identified pro and anti-migratory agents of airway smooth muscle cells, whether these agents can impact airway remodelling in the context of human asthma, remains to be elucidated. As such, further research is required to determine the exact mechanism behind airway smooth muscle cell migration within the airways, how much this contributes to airway smooth muscle mass in asthma, and whether attenuating this migration may provide a therapeutic avenue for asthma. In this review article, we will discuss the current evidence with respect to the regulation of airway smooth muscle cell migration in asthma.

Dynamic hyperinflation and exercise limitations in obese asthmatic women

Obese individuals and patients with asthma can develop dynamic hyperinflation (DH) during exercise; however, no previous study has investigated DH as a factor associated with reduced exercise capacity in obese asthmatic women. The aim of the present study was to examine the occurrence of DH and exercise limitations in obese asthmatics. Obese grade II [obese group (Ob-G); BMI 35-39.9 kg/m²; n=36] and nonobese [nonobese group (NOb-G); BMI 18.5-29.9 kg/m²; n=18] asthmatic patients performed a cardiopulmonary test to quantify peak V̇o₂ and a submaximal exercise test to assess DH. Anthropometric measurements, quadriceps endurance, and lung function were also evaluated. A forward stepwise regression was used to evaluate the association between exercise tolerance (wattage) and limiting exercise factors. Fifty-four patients completed the protocol. The Ob-G (n = 36) presented higher peak V̇o₂ values but lower power-to-weight ratio values than the NOb-G (P <0 .05). DH was more common in the Ob-G (72.2%) than in the NOb-G (38.9%, P < 0.05). The Ob-G had a greater reduction in the inspiratory capacity (-18 vs. -4.6%, P < 0.05). Exercise tolerance was associated with quadriceps endurance (r = 0.65; p<0.001), oxygen pulse (r = 0.52; p=0.001), and DH (r = -0.46, P = 0.005). The multiple regression analysis showed that the exercise tolerance could be predicted from a linear association only for muscular endurance (r = 0.82 and r² = 0.67). This study shows that dynamic hyperinflation is a common condition in obese asthmatics; they have reduced fitness for activities of daily living compared to nonobese asthmatics. However, peripheral limitation was the main factor associated with reduced capacity of exercise in these patients.NEW & NOTEWORTHY This is the first study to investigate the occurrence of dynamic hyperinflation (DH) in obese asthmatics. Our results demonstrate that obese asthmatics present a higher frequency and intensity of DH than nonobese asthmatics. We also show that physical deconditioning in this population is linearly associated with cardiac (O₂ pulse), respiratory (DH), and peripheral muscle (resistance) limitation. However, multiple linear regression demonstrated that peripheral muscle limitation may explain the exercise limitation in this population.

Obesity and Asthma: Microbiome-Metabolome Interactions

Obesity is a risk factor for asthma, but obese subjects with asthma respond poorly to standard asthma drugs. Obesity also alters gut bacterial community structure. Obesity-related changes in gut bacteria contribute to weight gain and other obesity-related conditions, including insulin resistance and systemic inflammation. Here, we review the rationale for the hypothesis that obesity-related changes in gut bacteria may also play a role in obesity-related asthma. The metabolomes of the liver, serum, urine, and adipose tissue are altered in obesity. Gut bacteria produce a large number of metabolites, which can reach the blood and circulate to other organs, and gut bacteria-derived metabolites have been shown to contribute to disease processes outside the gastrointestinal tract, including cardiovascular disease. Here, we describe the potential roles for two such classes of metabolites in obesity-related asthma: short-chain fatty acids and bile acids. Greater understanding of the role of microbiota in obesity-related asthma could lead to novel microbiota-based treatments for these hard-to-treat patients.

Impaired glucose metabolism and bronchial hyperresponsiveness in obese prepubertal asthmatic children

INTRODUCTION

The prevalence of asthma and obesity has risen in parallel over the last decades, but the exact mechanisms linking these two diseases still remain unclear. The aim of the present study was to investigate the associations between bronchial hyperresponsiveness (BHR), impaired glucose metabolism, obesity, and asthma in prepubertal children.

METHODS

A total of 71 prepubertal children were included in the study and divided in four groups according to the presence of asthma and their Body Mass Index (BMI): Group 1-Healthy Controls (HC), Group 2-Non Obese Asthmatics (NOA), Group 3-Obese Non Asthmatics (ONA), Group 4-Obese Asthmatics (OA) Αll children underwent spirometry and bronchial hyperresponsiveness testing by using the cumulative Provoking Dose of mannitol (PD_15, primary study variable); homeostasis model assessment-estimated insulin resistance (HOMA-IR) index was calculated in order to evaluate insulin resistance. Obese children also underwent an oral glucose tolerance testing (OGTT).

RESULTS

A statistically significant difference in bronchial hyperreactivity (mean ± SD) was detected in the group of obese asthmatic children who had lower values ​​of PD₁₅ , (174.16 ± 126.42) as compared to normal weight asthmatic children (453.93 ± 110.27), (P < 0.001). Moreover, obese asthmatic children with confirmed insulin resistance (HOMA-IR ≥2.5), had significantly lower PD₁₅ values (89.05 ± 42.75) as ​​compared to those with HOMA-IR <2.5 (259.27 ± 125.75), (P = 0.006). Finally, obese asthmatic children with impaired OGTT had likewise significantly lower PD₁₅ (81.02 ± 42.16) measurements as compared to children with normal OGTT (267.3 ± 112.62), (P = 0.001).

CONCLUSION

Our findings suggest that obesity per se does not correlate to airway hyperreactivity unless it is accompanied by glucose intolerance and insulin resistance. Pediatr Pulmonol. 2017;52:160-166. © 2016 Wiley Periodicals, Inc.

"Doing what I do best": The association between skill utilization and employee health with healthy behavior as a mediator

OBJECTIVE

Skill utilization, defined as having the opportunity to do one's best at work, has been examined as a contributor to productivity, organizational efficiency, job satisfaction, and mental health. Drawing from self-determination theory, we postulate that high levels of skill utilization are positively associated with physical health and that some of the effect is mediated by health behavior.

METHODS

Using the 2014 Gallup Daily Tracking Survey data (n = 87,316), a nationally representative sample of working adults in the United States, we examine the associations between perceived skill utilization and five health outcomes (self-rated health, hypertension, high cholesterol, cancer, asthma) with healthy behavior (regular exercising, fruits and vegetable consumption) as a mediator of the associations.

RESULTS

The regression results showed that a one-point increase in skill utilization (on a three-point scale) was associated with 20% lower odds of reporting poor or fair health, 3% and 8% lower odds of reporting hypertension and high cholesterol, but had no significant association with cancer or asthma. Health behavior mediated 10% of the association between skill utilization and self-rated health, 46% for hypertension, and 18% for high cholesterol.

CONCLUSION

The findings suggest that providing employees the opportunities to use their skills well at work improves health in general, and the effect is partly through enhancing the likelihood of engaging in healthy behaviors. Implications for organizational practice as well as future research directions are discussed.

Quality of Life and Health Outcomes in Overweight and Non-Overweight Children With Asthma

BACKGROUND

During the past two decades, the number of children and adolescents who are obese has more than doubled. Following this trend in childhood obesity, there has been an alarming increase in the number of children with asthma who are overweight.

OBJECTIVE

The aim of this study was to examine the differences in quality of life (QOL) and health outcomes of obese and overweight children with asthma compared with normal-weight children with asthma using a descriptive comparative survey design.

METHODS

This comparative study consisted of 90 overweight and normal-weight 9- to 14-year-olds with asthma. Health outcomes examined included asthma-related missed number of school days, emergency department (ED) visits, hospitalizations, number of days wheezing, and number of night awakenings. QOL was measured using the Pediatric Asthma Quality of Life Questionnaire.

RESULTS

The obese group reported the highest percentage of ED visits, hospitalizations, and number of days wheezing compared with the normal-weight group. A risk ratio analysis showed that the obese group had an overall 2.73 (95% confidence interval [CI] 2.15, 3.63) times higher likelihood of going to the ED and a 2.46 (95% CI 1.97, 3.19) times higher likelihood of hospitalization than the overweight and normal-weight groups. Asthma severity was a significant predictor of overall QOL (β = -23.737, p = .002).

CONCLUSIONS

The study results are consistent with other investigations that demonstrate that obese persons are at higher risk of experiencing severe asthma symptoms and support obesity as a potentially modifiable risk factor for asthma mitigation and prevention.

Nutrition and Immune System in Children with Simple Obesity

The purpose of this study was to evaluate dietary factors in nutrition influencing the immune system of children and teenagers suffering from simple obesity. The study involved 100 children and teenagers aged 7-18 with simple obesity. Nutritional data were obtained from 3-day food records. The consumed nutrients, including immunomodulators and immunostimulants, were estimated based on the nutrition interview. The results were compared with the nutritional norms. On average, the proportion of n-6:n-3 fatty acids equalled 10:1. Among the amino acids, the highest intake values in the diet were observed for glutamine (13,694.6 mg/day). The study demonstrates inadequate intake levels of iron (73% of recommended dietary allowance, RDA), vitamin C (65% of RDA), and vitamin D (11% of RDA) taking into account the median values for the entire study group. The median daily intake of other nutrients exceeded the RDA values. The diets of the participants in this study were not properly balanced with respect to immunomodulators, which may contribute to the occurrence of immunological disorders and immunodeficiency in this group of patients.

Therapy with resveratrol attenuates obesity-associated allergic airway inflammation in mice

Obesity and insulin resistance have been associated with deterioration in asthma outcomes. High oxidative stress and deficient activation of AMP-activated protein kinase (AMPK) have emerged as important regulators linking insulin resistance and inflammation. This study aimed to evaluate the effects of resveratrol on obesity-associated allergic pulmonary inflammation. Male C57/Bl6 mice fed with high-fat diet to induce obesity (obese group) or standard-chow diet (lean group) were treated or not with resveratrol (100mg/kg/day, two weeks). Mice were sensitized and challenged with ovalbumin (OVA). At 48h thereafter, bronchoalveolar lavage fluid was performed, and lungs collected for morphological studies and Western blot analysis. Treatment of obese mice with resveratrol significantly reduced hyperglycemia and insulin resistance, as well as the body measures (body mass, fat mass, % fat, and body area). OVA-challenge promoted a higher increase in pulmonary eosinophil infiltration in obese compared with lean mice, which was nearly abrogated by resveratrol treatment. Resveratrol markedly increased the phosphorylated AMPK expression in lung tissues of obese compared with lean mice. Resveratrol reduced the p47phox expression and reactive-oxygen species (ROS) production, and elevated the superoxide dismutase (SOD) levels in lung tissues of obese mice. The increased pulmonary levels of TNF-α and inducible nitric oxide synthase (iNOS) in obese mice were also normalized after resveratrol treatment. In lean mice, resveratrol failed to affect the levels of fasting glucose, p47phox, ROS levels, TNF-α, iNOS and phosphorylated AMPK. Resveratrol exhibits protective effects in obesity-associated lung inflammation that is accompanied by local AMPK activation and antioxidant property.

A systematic review of the relationship between asthma, overweight, and the effects of physical activity in youth

PURPOSE

The association of asthma and overweight in youth is well studied. However, the temporal relationship between asthma and overweight, the strength of their association, and mediating factors involved in this relationship remain unclear. This review investigates the relationship between asthma and overweight in youth, while examining the role of physical activity as a mediator.

METHODS

A systematic review of literature was conducted using PubMed and Medline databases. Studies conducted among youth aged 0-18 years, published in English between 2000-2014 were included. The Strengthening the Reporting of Observational Studies in Epidemiology guidelines were consulted to evaluate quality of selected citations.

RESULTS

A comprehensive search yielded 143 studies in PubMed and 133 studies in Medline databases. Of these, 75 studies met the eligibility criteria. The review found varying hypotheses regarding the temporal relationship between asthma and overweight in youth; existing evidence supports the mediation of this association by decreased expenditure of energy due to reduced physical activity. Negative self-perception or parental perception of exercise ability due to asthma symptoms secondary to physical exertion was identified as a determinant of physical activity in asthmatic youth.

CONCLUSIONS

Physical activity likely mediates the relationship between asthma and overweight in youth. Temporality of this relationship remains unclear.

Bronchial Asthma and Obesity in Childhood

Bronchial asthma and obesity is among a group of multietiologic complex diseases which influence each other in their origin, and development. The impact on the patient‘s quality of life and prognosis is significant, health costs included. Because of the increasing prevalence worldwide, there has been an increase in the amount of studies dealing with reciprocal associations between asthma and obesity.

Obesity risk class and asthma outpatient service utilization by the middle aged and elderly in Taiwan

BACKGROUND

According to the estimates of the World Health Organization (WHO), there were about 300 million people in the world suffering from asthma in 2005. Among the risk factors of asthma is obesity, which was found to be significantly associated with asthma in recent decades.

OBJECTIVES

In this study, we analyze the relationship between obesity risk class and asthma outpatient service utilization by the middle-aged and elderly in Taiwan.

METHODS

Adopting data from the 2005 Nation Health Interview Survey (NHIS) and National Health Insurance Research Database (NHIRD), we first utilize latent class analysis (LCA) to identify obesity risk classes. Next, we utilize a logit and a negative binominal model to analyze the relationship between each obesity risk class and asthma outpatient service utilization.

RESULTS

Results indicate that compared with the "overweight/obese with low consumption of vegetable/fruit and little exercise" class, the classes "normal-weight with high consumption of vegetable/fruit and moderate exercise" and "overweight/obese with high consumption of vegetable/fruit and moderate exercise" tend to have low probabilities and less number of visits of utilizing asthma outpatient services.

CONCLUSIONS

Our results may constitute useful references for clinicians and government policy makers formulating strategies for asthma management and prevention. Better informed strategies for asthma management could, in turn, increase the efficiency of asthmatic patients' care, which could provide efficient assistance to the target group based on the obesity risk classes.

Higher Body Mass Index and Increased Prevalence of Paranasal Sinus Disease

Background

We hypothesized that higher body mass index (BMI) was associated with increased prevalence of paranasal sinus disease and examined the hypothesis in Japanese adults.

Methods

This was a cross-sectional study including 1350 Japanese adults aged 40 years or more who participated in a health check-up program focusing on brain diseases and metabolic syndrome. Participants were divided into quartiles of BMI levels. Paranasal sinus disease was confirmed by a head MRI scan. The association between BMI and paranasal sinus disease was examined using logistic regression analysis, which was adjusted for age, sex, waist:hip ratio, hemoglobin A1c, systolic blood pressure, smoking status, alcohol intake, and white blood cell count.

Results

Of the 1350 participants, 151 (11.2%) had paranasal sinus disease. In relation to those in the lowest quartile of BMI, the odds ratios of having the disease among those in the 2nd, 3rd, and 4th quartiles of BMI were 1.89 (95% confidence interval [CI], 1.03–3.48), 2.26 (95% CI, 1.20–4.23) and 2.26 (95% CI, 1.14–4.51), respectively. When BMI was analysed as a continuous variable, an increase of one unit in BMI was significantly associated with increased odds of having the disease, with an OR of 1.08 (95% CI, 1.01–1.16).

Conclusions

The present study suggests that patients with higher BMI are more likely to have paranasal sinus disease.

Role of adiponectin in sphingosine-1-phosphate induced airway hyperresponsiveness and inflammation

Epidemiological data suggest that obesity represent an important risk factor for asthma, but the link between excess fat and airway hyperresponsiveness (AHR) and inflammation is not fully understood. Recently, a key role in physiopathologic conditions of lungs has been given to adiponectin (Acrp30). Acrp30 is one of the most expressed adipokines produced and secreted by adipose tissue, showing an intriguing relationship with metabolism of sphingolipids. Sphingosine-1-phosphate (S1P) has been proposed as an important inflammatory mediator implicated in the pathogenesis of airway inflammation and asthma. In the present study we analyze the effects of recombinant Acrp30 administration in an experimental model of S1P-induced AHR and inflammation. The results show that S1P is able to reduce endogenous Acrp30 serum levels and that recombinant Acrp30 treatment significantly reduce S1P-induced AHR and inflammation. Moreover, we observed a reduction of Adiponectin receptors (AdipoR1, AdipoR2 and T-cadherin) expression in S1P treated mice. Treatment with recombinant Acrp30 was able to restore Acrp30 serum levels and adiponectin receptors expression. These results could indicate the ability of S1P to modulate the Acrp30 action, by modulating not only the serum levels of the protein, but also its receptors. Taken together, these data suggest that adiponectin could represent a possible biomarker in obesity-associated asthma.

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.

Novel identification of the free fatty acid receptor FFAR1 that promotes contraction in airway smooth muscle

Obesity is one of the major risk factors for asthma. Previous studies have demonstrated that free fatty acid levels are elevated in the plasma of obese individuals. Medium- and long-chain free fatty acids act as endogenous ligands for the free fatty acid receptors FFAR1/GPR40 and FFAR4/GPR120, which couple to Gq proteins. We investigated whether FFAR1 and FFAR4 are expressed on airway smooth muscle and whether they activate Gq-coupled signaling and modulate airway smooth muscle tone. We detected the protein expression of FFAR1 and FFAR4 in freshly dissected native human and guinea pig airway smooth muscle and cultured human airway smooth muscle (HASM) cells by immunoblotting and immunohistochemistry. The long-chain free fatty acids (oleic acid and linoleic acid) and GW9508 (FFAR1/FFAR4 dual agonist) dose-dependently stimulated transient intracellular Ca(2+) concentration ([Ca(2+)]i) increases and inositol phosphate synthesis in HASM cells. Downregulation of FFAR1 or FFAR4 in HASM cells by small interfering RNA led to a significant inhibition of the long-chain free fatty acids-induced transient [Ca(2+)]i increases. Oleic acid, linoleic acid, or GW9508 stimulated stress fiber formation in HASM cells, potentiated acetylcholine-contracted guinea pig tracheal rings, and attenuated the relaxant effect of isoproterenol after an acetylcholine-induced contraction. In contrast, TUG-891 (FFAR4 agonist) did not induce the stress fiber formation or potentiate acetylcholine-induced contraction. These results suggest that FFAR1 is the functionally dominant free fatty acid receptor in both human and guinea pig airway smooth muscle. The free fatty acid sensors expressed on airway smooth muscle could be an important modulator of airway smooth muscle tone.

Fetal Growth, Obesity, and Atopic Disorders in Adolescence: a Retrospective Birth Cohort Study

BACKGROUND

Developmental status at birth and subsequent obesity have been implicated in the development of childhood atopic dermatitis (AD) and allergic rhinitis (AR).

METHODS

The current study analysed the cohort data of 74 688 junior high school students from a national retrospective birth cohort study in Taiwan. A random 10% sample was selected from singleton livebirths with complete data on the analytical variables of interest. Atopic disorders, including AD and AR, were assessed by questionnaires (International Study of Asthma and Allergies in Childhood). Logistic regression analyses were applied with adjustments for related risk factors.

RESULTS

Among subjects mainly 13-15 years of age, the estimated prevalence was 7.6% for AD and 22.4% for AR. While the role of fetal growth in allergic disorders was less evident, the risk of developing AD and AR were both influenced by a combination of fetal growth status and adolescent body mass index (BMI). Compared with those with normal fetal growth and school-aged BMI, the risk of developing AD increased 64% among adolescents with both restricted fetal growth and high BMI (odds ratio 1.64, 95% confidence interval 1.37, 1.97). The risk for this combination was higher than that for either restricted fetal growth or high BMI alone. Nevertheless, the overall interaction between BMI and fetal growth status on atopic disorders did not reach statistical significance.

CONCLUSIONS

Excessive weight gain could be an important risk factor related to developing atopic dermatitis and allergic rhinitis during adolescence, especially among infants born small for gestational age.

Obesity and bronchial obstruction in impulse oscillometry at age 5-7 years in a prospective post-bronchiolitis cohort

BACKGROUND AND AIMS

Obesity has been linked with asthma symptoms, need for asthma treatment and reduced lung function but not with increased bronchial reactivity in children. The aim of this study was to evaluate the association between previous or current weight status and current lung function and bronchial reactivity to exercise at early school age.

METHODS

Ninety-nine children hospitalized for bronchiolitis at the age of less than 6 months were studied with impulse oscillometry (IOS) at the mean age of 6.3 years. Data on birth weight and weight gain in infancy before hospitalization were collected during hospitalization. Current weight and height data were transformed into age- and sex-specific height-related body mass index z scores (zBMI) using the Finnish national population-based weight and height data as reference.

RESULTS

Some significant though only low or modest correlations were found between current zBMI and baseline, post-exercise and post-bronchodilator IOS values in adjusted linear regression analysis. Seven obese children by zBMI had higher post-bronchodilator airway impedance (Zrs) and resistance (Rrs) at 5 Hz and lower post-bronchodilator frequency dependency of resistance (dRrs/df) than normal weight children. There were no significant differences in responses to exercise or to bronchodilators between currently obese or overweight children and normal weight children. Birth weight less than 3,000 g was associated with larger exercise-induced changes in Zrs and Rrs at 5 Hz, and in reactance (Xrs) at 5 Hz, than those with birth weight more than 3,000 g.

CONCLUSIONS

Preliminary evidence was found that obesity may be associated with airway obstruction, but not with bronchial hyper-reactivity.

Adiponectin in Asthma and Obesity: Protective Agent or Risk Factor for More Severe Disease?

PURPOSE

The relationship between asthma and obesity is well established, although the pathophysiological mechanisms linking both diseases remain unknown. Adiponectin is a hormone secreted by adipose cells, plays a role in the modulation of inflammation and may be the key linking these two types of inflammation.

METHODS

We conducted a cross-sectional study with asthma with different body mass indices (BMI); the patients were classified as eutrophic, overweight, or obese. We assessed disease control using the GINA consensus, and the levels of adiponectin, C-reactive protein (CRP) and interleukin 33 (IL-33) in each of the patients.

RESULTS

We evaluated 75 of the 96 patients eligible for the study, including 25 in each BMI group. The CRP levels were significantly higher in the obese patients compared with both the eutrophic (p = 0.01) and the overweight (p = 0.03) patients. The mean adiponectin level was 21.82 ± 9.93 mg/L for the eutrophic asthmatics, which is a level that was significantly higher than in the overweight (15.31 ± 6.27 mg/L, p = 0.0140) and the obese (16.69 ± 11.45 mg/L, p = 0.0287) patients. The patients with higher adiponectin levels exhibited smaller FEV1 (p = 0.02) and lower FVC (p = 0.003). The IL-33 levels were not different between the groups.

CONCLUSIONS

Adiponectin does not protect against the development of inflammation in the setting of asthma and may in fact exacerbate the disease via its anti-TH1 inflammatory effects, allowing for increased TH2 differentiation and a more severe allergic response.

Does comorbid obesity impact quality of life outcomes in patients undergoing endoscopic sinus surgery?

BACKGROUND

Both obesity and chronic rhinosinusitis (CRS) are characterized by inflammation. Furthermore, both disease processes are independently associated with decreases in quality-of-life (QOL). We sought to investigate the role of comorbid obesity in QOL outcomes in CRS patients undergoing endoscopic sinus surgery (ESS).

METHODS

Adult patients with medically refractory CRS (n = 241) were prospectively enrolled into a multi-institutional treatment outcomes investigation. Body mass index (BMI) calculations were used to differentiate patient weight groups (normal weight: 18.5 to 24.9, overweight: 25.0 to 29.9; and obese: ≥30.0). Preoperative and postoperative QOL (Rhinosinusitis Disability Index [RSDI] and the 22-item Sino-Nasal Outcome Test [SNOT-22]) were evaluated compared across BMI groups and obesity subclasses.

RESULTS

The prevalence of comorbid obesity was 41% (n = 99). Higher prevalence of comorbid disease was found across increasing BMI groups including diabetes mellitus, asthma, and depression. No significant differences were found in mean preoperative QOL measures between any BMI groups. Significant improvement between preoperative and postoperative QOL mean scores (p ≤ 0.050) was found for all BMI groups. Despite no significant difference in mean QOL improvement between BMI groups (p ≥ 0.142), overweight and obese patients reported reduced relative mean percentage (%) improvement compared to normal weight participants on the RSDI total score (33% and 37% vs 55%, respectively) and SNOT-22 total score (29% and 40% vs 48%, respectively).

CONCLUSION

Patients with comorbid obesity experience significant improvement in average QOL gains following ESS though the percentage of relative improvement in QOL may be decreased in patients with comorbid obesity and CRS as compared to those without.

Alterations in Lung Functions Based on BMI and Body Fat % Among Obese Indian Population at National Capital Region

BACKGROUND

In India, non-asthmatic hospital admission case study has been conducted to find out the relationship between obesity and lung functions. The main objective of the present study was to find out the alterations in lung functions due to obesity among Indian population living at National Capital Region (NCR).

MATERIALS AND METHODS

We examined 609 non obese and 211 obese subjects in a cross sectional study from National Capital Region, India with age group ranges between 18-70 years. BMI and body fat % was determined using body fat analyzer. Obese and non-obese subjects were classified based on criteria for BMI and Body fat %. Lung function test viz., FEV1 and PEFR were conducted using portable spirometer (PIKO-1).

RESULTS

A significant correlation (p<0.05) was observed between BMI and PEFR among non-obese male and female subjects. Decline in PEFR and FEV1 values for corresponding increase in body fat % was observed among study subjects. A significant (p<0.01) decline in mean FEV1 and PEFR was observed among non-obese and obese subjects, compared to their Indian reference standards for lung functions. A significant negative correlation (p<0.01) was observed between body fat % and lung functions (FEV1, PEFR).

CONCLUSION

It is concluded that obese subjects are at a risk of lung function impairment, based on the criteria followed for BMI and body fat %. The study also demonstrate that body fat% classification as a better index for determination of obese subjects compared to BMI classification, with respect to lung function impairments.

Excess weight in preschool children with a history of severe bronchiolitis is associated with asthma

BACKGROUND

The relationship between excess weight gain and asthma in childhood remains inadequately defined. The aim of this study was to evaluate, as part of a prospective post-bronchiolitis follow-up, whether there is a link between earlier or current overweight or obesity and asthma or asthma symptoms at 5-7 years of age.

METHODS

In all, 151 former bronchiolitis patients were followed-up until the mean age of 6.45 years. At the control visit, the weights and heights were measured, and the asthma symptoms and medications for asthma were recorded. The weight status was expressed as body mass index (BMI) z-scores (zBMI).

RESULTS

There were 10 obese and 31 overweight (zBMI over national references) children. In adjusted analyses, presence of current asthma at 6-7 years of age (aOR 3.05, 95% CI 1.02-9.93) differed between overweight and normal weight children. Further, asthma ever, asthma at age 4-5 years, asthma at age 5-6 years, use of bronchodilators ever and use of ICSs during the last 12 months were more common in currently overweight than in normal weight children. Obesity was associated only with current asthma and asthma ever. Instead, there were no significant associations between birth weight, excess weight gain in infancy, or overweight at age 1.5 years, and later asthma, asthma symptoms or use of asthma medication.

CONCLUSION

Asthma was more common in currently overweight than in normal weight former bronchiolitis patients at preschool age and early school age.

Innate and ozone-induced airway hyperresponsiveness in obese mice: role of TNF-α

Innate airway hyperresponsiveness (AHR) and augmented responses to ozone, an asthma trigger, are characteristics of obese mice. Systemic inflammation, a condition of increased circulating concentrations of inflammatory moieties, occurs in obesity. We hypothesized that TNF-α, via its effects as a master effector of this systemic inflammation, regulates innate AHR and augmented responses to ozone in obese mice. Therefore, we examined pulmonary inflammation and airway responsiveness in unexposed or ozone-exposed (2 ppm for 3 h) lean wild-type and obese Cpe(fat) mice that were TNF-α sufficient or deficient. Cpe(fat) mice lack carboxypeptidase E, which regulates satiety. Compared with wild type, Cpe(fat) mice had elevated serum IL-17A, G-CSF, KC, MCP-1, IL-9, MIG, and leptin, indicating systemic inflammation. Despite reductions in most of these moieties in TNF-α-deficient vs. -sufficient Cpe(fat) mice, we observed no substantial difference in airway responsiveness in these two groups of mice. Ozone-induced increases in bronchoalveolar lavage (BAL) neutrophils and macrophages were lower, but ozone-induced AHR and increases in BAL hyaluronan, osteopontin, IL-13, and protein carbonyls, a marker of oxidative stress, were augmented in TNF-α-deficient vs. -sufficient Cpe(fat) mice. Our data indicate that TNF-α has an important role in promoting the systemic inflammation but not the innate AHR of obesity, suggesting that the systemic inflammation of obesity is not the major driver of this AHR. TNF-α is required for the augmented effects of acute ozone exposure on pulmonary inflammatory cell recruitment in obese mice, whereas TNF-α protects against ozone-induced AHR in obese mice, possibly by suppressing ozone-induced oxidative stress.

Leukotriene production is increased in abdominal obesity

Obesity is a major risk factor for insulin resistance and type-2 diabetes. A chronic low grade inflammatory state has been described during obesity and associated with insulin resistance pathogenesis. Results from animal studies are in favor of a role of the leukotriene (LT) pathway in obesity induced-insulin resistance. However, there is a paucity of data regarding this association in human obesity. Therefore, the aim of this study was to investigate whether LT production was associated with insulin resistance and other metabolic parameters in a cohort of obese subjects. Forty-six (70% females) obese subjects (BMI≧30 kg/m²) without known diabetes and without inflammatory disease (CRP<10 mg/l) were included. Median age was 44 years (16–80) with a median BMI of 36.8 kg/m² (30–51). Insulin resistance was evaluated by HOMA-IR index and glucose tolerance test. Urinary LTE₄ (U-LTE₄) concentration was measured by enzyme immune assay. Screening for obstructive sleep apnea was performed. There was a positive association of U-LTE₄ with waist to hip ratio, systolic blood pressure and HOMA-IR in univariate analysis. Further, waist to hip ratio remained the only parameter significantly correlated with U-LTE₄, in adjusted multivariate analysis. Taken together, these results confirm the previously established notion of chronic low grade inflammation in obesity and further suggests a role for the LT pathway in obesity-associated development of insulin resistance in humans.