Prospective Study on the Relationship of Obesity to Asthma Impairment and Risk

Obesity: Next game changer of allergic airway diseases?

Obesity and allergic diseases are global health concerns, both of which are seeing an increase in prevalence in recent years. Obesity has been recognised as an important comorbidity in subpopulations with allergic airway diseases, which represents a unique phenotype and endotype. Obesity-related allergic airway diseases are associated with exacerbated clinical symptom burden, altered immune response, increased disease severity and compromised predictive capability of conventional biomarkers for evaluating endotype and prognosis. Moreover, treatment of obesity-related allergic airway diseases is challenging because this unique endotype and phenotype is associated with poor response to standard therapeutic strategies. Therapeutic regimen that involves weight loss by non-surgical and surgical interventions, gut microbiome-targeted treatment, glucagon-like peptide-1 receptor agonist and other agents should be considered in this population. In this review, we outline the current knowledge of the impact of obesity on prevalence, endotypes, clinical symptom and management of allergic airway diseases. Increased understanding of the implications of obesity may contribute to better treatment options for the obesity-related refractory airway inflammation, particularly in precision medicine. KEY POINTS: Obesity can increase the prevalence of allergic airway diseases such as asthma, AR, and CRSwNP. Obesity alters the immune endotype and exacerbates clinical symptoms of respiratory allergic diseases. Obesity-related allergic airway diseases exhibit therapeutic resistance to standard treatment. Obesity-related allergic airway diseases constitute a distinct category of endotypes and phenotypes, requiring further in-depth research and novel therapeutic approaches.

Obesity Enhances Non-Th2 Airway Inflammation in a Murine Model of Allergic Asthma

Obese patients with asthma present with aggravated symptoms that are also harder to treat. Here, we used a mouse model of allergic asthma sensitised and challenged to house dust mite (HDM) extracts to determine whether high-fat-diet consumption would exacerbate the key features of allergic airway inflammation. C57BL/6 mice were intranasally sensitised and challenged with HDM extracts over a duration of 3 weeks. The impact of high-fat-diet (HFD) vs. normal diet (ND) chow was studied on HDM-induced lung inflammation and inflammatory cell infiltration as well as cytokine production. HFD-fed mice had greater inflammatory cell infiltration around airways and blood vessels, and an overall more severe degree of inflammation than in the ND-fed mice (semiquantitative blinded evaluation). Quantitative assessment of HDM-associated Th2 responses (numbers of lung CD4+ T cells, eosinophils, serum levels of allergen-specific IgE as well as the expression of Th2 cytokines (Il5 and Il13)) did not show significant changes between the HFD and ND groups. Interestingly, the HFD group exhibited a more pronounced neutrophilic infiltration within their lung tissues and an increase in non-Th2 cytokines (Il17, Tnfa, Tgf-b, Il-1b). These findings provide additional evidence that obesity triggered by a high-fat-diet regimen may exacerbate asthma by involving non-Th2 and neutrophilic pathways.

Systemic Inflammation in Asthma: What Are the Risks and Impacts Outside the Airway?

Airway inflammation in asthma has been well recognized for several decades, with general agreement on its role in asthma pathogenesis, symptoms, propensity toward exacerbation, and decline in lung function. This has led to universal recommendation in asthma management guidelines to incorporate the use of inhaled corticosteroid as an anti-inflammatory therapy for all patients with persistent asthma symptoms. However, there has been limited attention paid to the presence and potential impact of systemic inflammation in asthma. Accumulating evidence from epidemiological observations and cohort studies points to a host of downstream organ dysfunction in asthma especially among patients with longstanding or more severe disease, frequent exacerbations, and underlying risk factors for organ dysfunction. Most studies to date have focused on cognitive impairment, depression/anxiety, metabolic syndrome, and cardiovascular abnormalities. In this review, we summarize some of the evidence demonstrating these abnormalities and highlight the proposed mechanisms and potential benefits of treatment in limiting these extrapulmonary abnormalities in patients with asthma. The goal of this commentary is to raise awareness of the importance of recognizing potential extrapulmonary conditions associated with systemic inflammation of asthma. This area of treatment of patients with asthma is a large unmet need.

Tropical high altitude and severe asthma in adults: house dust mite sensitization and phenotypic distribution

BACKGROUND

There is a lack of information on house dust mite (HDM) sensitization and phenotype distribution in patients with severe asthma (SA) living permanently at high-altitude (HA) in tropical regions, which may be different.

OBJECTIVE

The aim of this study was to characterize adults with SA in a tropical high altitude city (2,640 m): Bogotá, Colombia.

MATERIAL AND METHODS

This observational cross-sectional study included severe asthmatic outpatients (n = 129) referred to the ASMAIRE program of the Fundación Neumológica Colombiana in Bogotá (2,640 m). Clinical history, spirometry, total IgE, blood eosinophils, and skin prick test (SPT), including HDM allergens, were performed. Phenotype definitions: Allergic/atopic (AA): IgE ≥100 IU/mL and/or at least one positive SPT; eosinophilic (EOS): blood eosinophils ≥300 cells/µL; type 2-high: AA and/or EOS phenotype; type 2-low: non-AA/non-EOS phenotype (IgE <100 IU/mL, negative SPT, and blood eosinophils <300 cells/µL).

RESULTS

A total of 129 adults with SA were included, 79.8% female. Phenotype distribution: AA: 61.2%; EOS: 37.2%; type 2-high: 72.1%; type 2-low: 27.9%. Among AA patients, HDM sensitization was present in 87% and 34.9% were non-eosinophilic. There was a significant overlap between the phenotypes.

CONCLUSIONS

In contrast to non-tropical high-altitude regions, we found a high frequency of HDM sensitization in patients with AA phenotype living in a tropical high-altitude city. We also found a discrete lower frequency of EOS phenotype with no other significant differences in the phenotypic distribution compared to that described at low altitudes. We propose that tropical location may modify the effect of high altitude on HDM concentrations and allergenicity.

Obesity alters immunopathology in cancers and inflammatory diseases

Obesity is characterized by chronic low-grade inflammation and is strongly associated with multiple immunological diseases, including cancer and inflammatory diseases. Recent animal studies revealed that obesity-induced immunological changes worsen immune-driven diseases and cause resistance to immunotherapy. Here, we discuss the role of obesity in the immunopathology and treatment responses of cancers, respiratory and allergic diseases, and IL-17-mediated inflammatory diseases. We summarize the unique features of the inflammatory state of these diseases, which are orchestrated by obesity. In particular, obesity alters the immune landscape in cancers with a reprogrammed metabolic profile of tumor-infiltrating immune cells. Obesity exacerbates airway inflammation by dysregulating multiple immune-cell subsets. Obesity also dysregulates Th17, IL-17-producing mucosal-associated invariant T (MAIT), and γδ T cells, which contribute to IL-17-mediated inflammatory response in multiple sclerosis, inflammatory bowel disease, psoriasis, atopic dermatitis, and rheumatoid arthritis. By identifying the effects of obesity on immunological diseases, new strategies could be devised to target immune dysregulation caused by obesity.

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.

Aging-Related Mechanisms Contribute to Corticosteroid Insensitivity in Elderly Asthma

Asthma in elderly populations is an increasing health problem that is accompanied by diminished lung function and frequent exacerbations. As potent anti-inflammatory drugs, corticosteroids are commonly used to reduce lung inflammation, improve lung function, and manage disease symptoms in asthma. Although effective for most individuals, older patients are more insensitive to corticosteroids, making it difficult to manage asthma in this population. With the number of individuals older than 65 continuing to increase, it is important to understand the distinct mechanisms that promote corticosteroid insensitivity in the aging lung. In this review, we discuss corticosteroid insensitivity in asthma with an emphasis on mechanisms that contribute to persistent inflammation and diminished lung function in older individuals.

Risankizumab in Severe Asthma - A Phase 2a, Placebo-Controlled Trial

BACKGROUND

Interleukin-23 has been implicated in airway inflammation that is mediated by type 2 and type 17 cytokines. Whether targeting interleukin-23 in the treatment of asthma improves disease control and reduces airway inflammation is unclear.

METHODS

We conducted a phase 2a, multicenter, randomized, double-blind, placebo-controlled, 24-week, parallel-group trial to assess the efficacy and safety of risankizumab, an anti-interleukin-23p19 monoclonal antibody, in adults with severe asthma. Patients were assigned to receive 90 mg of risankizumab or placebo, administered subcutaneously once every 4 weeks. The primary end point was the time to the first asthma worsening. Asthma worsening was defined as deterioration from baseline on 2 or more consecutive days; deterioration was considered to be a decrease of at least 30% in the morning peak expiratory flow or an increase from baseline of at least 50% in the number of puffs of rescue medication in a 24-hour period (equating to at least four additional puffs), a severe asthma exacerbation, or an increase of 0.75 or more points on the 5-item Asthma Control Questionnaire (ACQ-5; scores range from 0 to 6, with higher scores indicating less control). Secondary end points were the annualized rate of asthma worsening, the annualized rate of severe exacerbations, the ACQ-5 score, and the forced expiratory volume in 1 second. Exploratory end points were assessed with the use of sputum cytologic analysis and gene expression analysis, and safety was assessed.

RESULTS

A total of 105 patients received risankizumab and 109 received placebo. The clinical characteristics of the patients were similar in the two groups. The time to the first asthma worsening was shorter with risankizumab than with placebo (median, 40 days vs. 86 days; hazard ratio, 1.46; 95% confidence interval [CI], 1.05 to 2.04; P = 0.03). The rate ratio for annualized asthma worsening with risankizumab as compared with placebo was 1.49 (95% CI, 1.12 to 1.99), and the rate ratio for severe exacerbations was 1.13 (95% CI, 0.75 to 1.70). Sputum transcriptomic pathway analysis showed that genes involved in the activation of natural killer cells and cytotoxic T cells and the activation of the type 1 helper T and type 17 helper T transcription factors were down-regulated by risankizumab. No safety concerns were associated with risankizumab therapy.

CONCLUSIONS

Risankizumab treatment was not beneficial in severe asthma. The time to the first asthma worsening was shorter and the annualized rate of asthma worsening was higher with risankizumab than with placebo. (Funded by AbbVie and Boehringer Ingelheim; ClinicalTrials.gov number, NCT02443298.).

Long-term prognosis of new adult-onset asthma in obese patients

Background

Obesity has been associated with poor outcomes of asthma in cross-sectional studies, but long-term effect of obesity on asthma remains unknown.

Aims

To study the effects of obesity, found at the time of diagnosis of adult-onset asthma, on 12-year prognosis by focusing on oral corticosteroid (OCS) use and respiratory-related hospital admissions.

Methods

Patients diagnosed with adult-onset asthma (n=203) were divided into three categories based on diagnostic body mass index (BMI) (<25 kg·m⁻², 25–29.9 kg·m⁻², ≥30 kg·m⁻²) and followed for 12 years as part of the Seinäjoki Adult Asthma Study. Self-reported and dispensed OCS were assessed for the 12-year period. Data on hospital admissions were analysed based on medical records.

Results

12 years after diagnosis, 86% of the patients who were obese (BMI ≥30 kg·m⁻²) at diagnosis remained obese. During the follow-up, no difference was found in weight gain between the BMI categories. During the 12-year follow-up, patients obese at diagnosis reported more frequent use of OCS courses (46.9% versus 23.1%, p=0.028), were dispensed OCS more often (81.6% versus 56.9%, p=0.014) and at higher doses (median 1350 (interquartile range 280–3180) mg versus 600 (0–1650) mg prednisolone, p=0.010) compared to normal-weight patients. Furthermore, patients who were obese had more often one or more respiratory-related hospitalisations compared to normal-weight patients (38.8% versus 16.9%, p=0.033). In multivariate logistic regression analyses, obesity predicted OCS use and hospital admissions.

Conclusions

In adult-onset asthma, patients obese at diagnosis mostly remained obese at long-term and had more exacerbations and respiratory-related hospital admissions compared to normal-weight patients during 12-year follow-up. Weight loss should be a priority in their treatment to prevent this outcome.

Obese patients with new adult-onset asthma often remain obese in the long-term and have more exacerbations and respiratory-related hospital admissions during follow-up. High priority should be given to weight loss during treatment to prevent this outcome.https://bit.ly/2G5HtRZ

Asthma medication use in obese and healthy weight asthma: systematic review/meta-analysis

BACKGROUND

Obesity is a common comorbidity in asthma and associated with poorer asthma control, more frequent/severe exacerbations, and reduced response to asthma pharmacotherapy.

OBJECTIVE

This review aims to compare use of all classes of asthma medications in obese (body mass index (BMI) ≤30 kg·m^-2) versus healthy-weight (BMI <25 kg·m^-2) subjects with asthma.

DESIGN

Databases including CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, Embase and MEDLINE were searched up to July 2019 for English-language studies that recorded medication use or dose in obese and healthy-weight adults with asthma. A critical appraisal checklist was utilised for scrutinising methodological quality of eligible studies. Meta-analysis was performed and heterogeneity was examined with the use of the Chi-squared test. This review was conducted based on a published protocol (www.crd.york.ac.uk/PROSPERO CRD42020148671).

RESULTS

Meta-analysis showed that obese subjects are more likely to use asthma medications, including short-acting β₂-agonists (OR 1.75, 95% CI 1.17-2.60; p=0.006, I²=41%) and maintenance oral corticosteroids (OR 1.86, 95% CI 1.49-2.31; p<0.001, I²=0%) compared to healthy-weight subjects. Inhaled corticosteroid (ICS) dose (µg·day^-1) was significantly higher in obese subjects (mean difference 208.14, 95% CI 107.01-309.27; p<0.001, I²=74%). Forced expiratory volume in 1 s (FEV₁) % predicted was significantly lower in obese subjects (mean difference -5.32%, 95% CI -6.75--3.89; p<0.001, I²=42%); however, no significant differences were observed in FEV₁/forced vital capacity (FVC) ratio between groups.

CONCLUSIONS

We found that obese subjects with asthma have higher use of all included asthma medication classes and higher ICS doses than healthy-weight asthma subjects, despite lower FEV₁ and a similar FEV₁/FVC %. A better understanding of the factors driving increased medication use is required to improve outcomes in this subgroup of asthmatics.

Systematic Literature Review of Systemic Corticosteroid Use for Asthma Management

Systemic corticosteroid use to manage uncontrolled asthma and its associated healthcare burden may account for important health-related adverse effects. We conducted a systematic literature review to investigate the real-world extent and burden of systemic corticosteroid use in asthma. We searched MEDLINE and Embase databases to identify English-language articles published in 2010–2017, using search terms for asthma with keywords for oral corticosteroids and systemic corticosteroids. Observational studies, prescription database analyses, economic analyses, and surveys on oral/systemic corticosteroid use in children (>5 yr old), adolescents (12–17 yr old), and adults with asthma were included. We identified and reviewed 387 full-text articles, and our review included data from 139 studies. The included studies were conducted in Europe, North America, and Asia. Overall, oral/systemic corticosteroids were commonly used for asthma management and were more frequently used in patients with severe asthma than in those with milder disease. Long-term oral/systemic corticosteroid use was, in general, less frequent than short-term use. Compared with no use, long-term and repeated short-term oral/systemic corticosteroid use were associated with an increased risk of acute and chronic adverse events, even when doses were comparatively low. Greater oral/systemic corticosteroid exposure was also associated with increased costs and healthcare resource use. This review provides a comprehensive overview of oral/systemic corticosteroid use and associated adverse events for patients with all degrees of asthma severity and exposure duration. We report that oral/systemic corticosteroid use is prevalent in asthma management, and the risks of acute and chronic complications increase with the cumulative oral corticosteroid dosage.

Comorbid Obesity and Depressive Symptoms in Childhood Asthma: A Harmful Synergy

BACKGROUND

Overweight/obesity (OV/OB) and depression have each been separately associated with worsened childhood asthma severity and control. Pathways by which these factors may jointly affect childhood asthma have not been elucidated.

OBJECTIVE

To examine the interrelationship of OV/OB and depressive symptoms with childhood asthma and explore associated psychobiologic pathways. The present study investigated whether comorbid OV/OB and depressive symptoms are associated with impaired baseline lung function and increased airway resistance during emotional stress, and to assess whether such effects may be mediated by autonomic nervous system (ANS) dysregulation, specifically through predominance of vagal over sympathetic reactivity (vagal bias).

METHODS

A total of 250 children with asthma, aged 7 to 17, were assessed for OV/OB using body mass index, depressive symptoms using the Children's Depression Inventory (CDI), and asthma severity using National Asthma Education and Prevention Program Expert Panel Report 3 criteria. Baseline pulmonary function (forced expiratory volume in 1 second [FEV₁]) was assessed. The film "E.T. the Extra-Terrestrial" was used in a laboratory paradigm to evoke emotional stress/arousal. Airway resistance (R_int) was measured before and after the film to determine changes in airway function. ANS reactivity was assessed by measuring parasympathetic/vagal and sympathetic reactivity throughout the film.

RESULTS

In OV/OB children with asthma, depressive symptoms predicted lower baseline FEV₁ (β = -0.67, standard error [SE] = 0.24, P = .008), CDI predicted vagal bias under emotion stress/arousal (β = 0.27, SE = 0.09, P = .009), and vagal bias predicted increased R_int (β = 3.55, SE = 1.54, P = .023).

CONCLUSION

This study is the first to link OV/OB and depressive symptoms in their relationship to childhood asthma. In OV/OB children with asthma, depression may potentiate airway compromise, mediated by vagal bias. Use of antidepressant and anticholinergic therapies should be studied in this subgroup of patients.

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 in Adults

Asthma affects approximately 300 million people worldwide and approximately 7.5% of adults in the United States. Asthma is characterized by inflammation of the airways, variable airflow obstruction, and bronchial hyperresponsiveness. The diagnosis of asthma is a clinical one with the history and physical examination being significant, but objective measures, such as pulmonary function testing, can be used to aid in the diagnosis. There are multiple associated comorbidities with asthma, including rhinitis, sinusitis, gastroesophageal reflux disease, obstructive sleep apnea, and depression. There is often an allergic component of asthma, and patient education is vital.

Excessive Body Weight and Immunological Response in Children with Allergic Diseases

The prevalence of allergy and obesity is sharply on the rise in children. However, the nature of a mutual relation of the two conditions remains unclear. The aim of the study was to assess the impact of excessive body weight on the immune response in children with allergies. There were 56 children with allergies, aged 4-15 years, included into the study (41 with asthma and 15 with atopic dermatitis). Based on the body mass index, children were divided into two groups: normal weight (body mass index (BMI) <85th percentile) and excessive weight (BMI ≥ 85th percentile). The immunological parameters were evaluated by flow cytometry. We found that children with excessive body weight had a significantly lower percentage of CD4⁺ lymphocytes and a higher percentage of natural killer T cells (NKT) and CD16/56⁺ lymphocytes than those with normal weight. In the group with allergy, a significant positive association was noticed between BMI and the percentage of human leukocyte antigen (HLA)-DR-specific CD3. Further analysis was done after dividing the allergy group into the children with normal and excessive weight. There were an adverse association between BMI and the percentage of CD8⁺ lymphocytes in those with normal weight and a positive one between BMI and the percentage of CD4⁺ in those with excessive weight. We conclude that excessive body weight plays a major role in mediating the immunological response in children with allergy.

Asthma medication usage is significantly reduced following bariatric surgery

INTRODUCTION

Asthma is an important healthcare problem affecting millions in the United States. Additionally, a large proportion of patients with asthma suffer from obesity. These patients exhibit poor asthma control and reduced therapy response, increasing utilization of healthcare resources. Pulmonary symptoms improve after bariatric surgery (BS), and we hypothesized that asthma medication usage would decrease following BS.

METHODS

A retrospective data analysis was performed in adult patients from a single institution's database. Patients with obesity using at least one asthma medication pre-operatively who underwent BS were studied for up to 3-years post-operation. Poisson generalized linear mixed models for repeated measures were used to evaluate the effects of time and procedure type on the number of asthma medication.

RESULTS

Bariatric patients with at least one prescribed asthma medication (mean 1.4 ± 0.6) were included (n = 751). The mean age at time of operation was 46.8 ± 11.6 years, mean weight was 295.9 ± 57 lbs, and mean body mass index (BMI) was 49 ± 8.2 kg/m2; 87.7% were female, 33.4% had diabetes, 44.2% used gastroesophageal reflux disease (GERD) medication, and 64.4% used hypertension medication. The most common procedure was Roux-en-Y gastric bypass (79%), followed by sleeve gastrectomy (10.7%), adjustable gastric banding (8.1%), and duodenal switch (2.3%). The mean number of prescribed asthma medications among all procedures decreased by 27% at 30 days post-operation (p < 0.0001), 37% at 6 months (p < 0.0001), 44% at 1 year (p < 0.0001), and 46% at 3 years (p < 0.0001) after adjusting for risk factors. No significant differences in medication use over time between procedure types were observed. In the adjusted analysis, the mean number of asthma medications was 12% higher in patients using at least one GERD medication (p = 0.015) and 8% higher with 10-unit increase in pre-operative BMI (p = 0.006).

CONCLUSION

BS significantly decreases asthma medication use starting 30 days post-operation with a sustained reduction for up to 3 years.

A review on the pathophysiology of asthma remission

Asthma is a chronic respiratory condition, which is highly prevalent worldwide. Although no cure is currently available, it is well recognized that some asthma patients can spontaneously enter remission of the disease later in life. Asthma remission is characterized by absence of symptoms and lack of asthma-medication use. Subjects in asthma remission can be divided into two groups: those in clinical remission and those in complete remission. In clinical asthma remission, subjects still have a degree of lung functional impairment or bronchial hyperresponsiveness, while in complete asthma remission, these features are no longer present. Over longer periods, the latter group is less likely to relapse. This remission group is of great scientific interest due to the higher potential to find biomarkers or biological pathways that elicit or are associated with asthma remission. Despite the fact that the definition of asthma remission varies between studies, some factors are reproducibly observed to be associated with remitted asthma. Among these are lower levels of inflammatory markers, which are lowest in complete remission. Additionally, in both groups some degree of airway remodeling is present. Still, the pathological disease state of asthma remission has been poorly investigated. Future research should focus on at least two aspects: further characterisation of the small airways and airway walls in order to determine histologically true remission, and more thorough biological pathway analyses to explore triggers that elicit this phenomenon. Ultimately, this will result in pharmacological targets that provide the potential to steer the course of asthma towards remission.

Is aging a "comorbidity" of asthma?

The aging population is growing at an unparalleled rate. Asthma is common in the elderly (age over 65 years) and can be more severe with little chance for remission. Asthma in older individuals is often under-diagnosed, misdiagnosed and frequently under-treated. Concomitant medical and psychosocial conditions are more prevalent in the elderly and can obfuscate the presentation of asthma and make it more difficult to assess and manage. While these comorbidities are important in understanding elderly asthma, aging itself can be considered a "comorbidity" since it impacts structural and functional changes in the lung. Structural changes of the aging lung may worsen physiologic function in asthma. The immune system also changes with age, with increased vulnerability to pathogens and differences in airway inflammation, leading to variability in how asthma manifests and responds to treatment. The fact that aging can influence the severity and presentation of asthma along with its diagnosis and management is important for the treating physician to understand. This article will discuss the multitude of factors that justify considering aging as a comorbidity of asthma.

BMI at school age and incident asthma admissions in early adulthood: a prospective study of 310,211 children

Background

Excess body weight in adulthood is associated with risk for asthma admission (AA). Our aim was to investigate if this association also applies to the relation between body mass index (BMI) in childhood and AAs in early adulthood (age 20–45 years).

Methods

This was a prospective study of 310,211 schoolchildren (born 1930–1989) from the Copenhagen School Health Records Register. Height and weight were measured annually, and generated BMI z-scores were categorized as low (lower quartile), normal (interquartile) and high (upper quartile). Associations between BMI at ages 7–13 and AA were estimated by Cox regressions, and presented as hazard ratios (HRs) and 95% confidence intervals (CI). Main outcome was incident hospital AAs (extracted from the Danish National Patient Register) in early adulthood.

Results

During 4,708,607 person-years of follow-up, 1,813 incident AAs were observed. Nonlinear associations were detected between childhood BMI and AAs. The risk of AA increased for females in the highest BMI category in childhood, with the highest HR of 1.3 (95% CI 1.16–1.55) at the age of 13 years. By contrast, males in the low BMI category had a higher risk of AA in early adulthood, with the highest HR of 1.24 (95% CI 1.03–1.51) at the age of 12 years. Females with an increase in BMI between ages 7 and 13 years had an increased risk of AA compared with females with stable BMI (HR 1.28, 95% CI 1.10–1.50).

Conclusion

The association between childhood BMI and AA in early adulthood is non-linear. High BMI increases the risk of AA in females, whereas low BMI increases the risk in males.

Adiposity and Asthma in a Nationwide Study of Children and Adults in the United States

RATIONALE

Although obesity has been associated with asthma, body mass index is suboptimal to fully characterize adiposity.

OBJECTIVES

We examined the relation between adiposity and asthma in a large sample of the U.S. population, using indices defined by dual-energy X-ray absorptiometry.

METHODS

We analyzed data from 8,886 children (aged 8-19 yr) and 12,795 adults (aged 20-69 yr) from the 2001 to 2006 National Health and Nutrition Examination Survey. In addition to body mass index, percent body fat, waist circumference, and waist-to-height ratio, dual-energy X-ray absorptiometry was used to calculate whole-body and local adiposity indices: fat mass index; total, trunk, and legs percent fat; and trunk-to-total fat mass ratio, legs-to-total fat mass ratio, and trunk-to-legs fat mass ratios. Logistic regression was used for the analysis of adiposity measures and asthma.

RESULTS

Among children, general adiposity was significantly associated with asthma, with no major differences by sex. Results were driven by nonatopic children, in whom trunk-predominant (central) adiposity (assessed by waist circumference, waist-to-height ratio, trunk-to-total fat mass ratio, and trunk-to-legs fat mass ratio) was also associated with asthma. There were no significant associations among atopic children. Among adults, all adiposity indices were associated with asthma, with central adiposity significant only among women. The results in adults were driven by atopy, especially in women.

CONCLUSIONS

Adiposity measured by dual-energy X-ray absorptiometry provides similar information to that obtained by using anthropometric indices among children of both sexes and among adult men. However, dual-energy X-ray absorptiometry provides additional information in adult women, in whom dual-energy X-ray absorptiometry-measured central adiposity is significantly associated with asthma, particularly atopic asthma.

Dietary omega-6, but not omega-3, polyunsaturated or saturated fatty acids increase inflammation in primary lung mesenchymal cells

Obesity is an important risk factor for developing severe asthma. Dietary fatty acids, which are increased in sera of obese individuals and after high-fat meals, activate the innate immune system and induce inflammation. This study investigated whether dietary fatty acids directly cause inflammation and/or synergize with obesity-induced cytokines in primary human pulmonary fibroblasts in vitro. Fibroblasts were challenged with BSA-conjugated fatty acids [ω-6 polyunsaturated fatty acids (PUFAs) and ω-3 PUFAs or saturated fatty acids (SFAs)], with or without TNF-α, and release of the proinflammatory cytokines, IL-6 and CXCL8, was measured. We found that the ω-6 PUFA arachidonic acid (AA), but not ω-3 PUFAs or SFAs, upregulates IL-6 and CXCL8 release. Combined AA and TNF-α challenge resulted in substantially greater cytokine release than either alone, demonstrating synergy. Synergistic upregulation of IL-6, but not CXCL8, was mainly mediated via cyclooxygenase (COX). Inhibition of p38 MAPK reduced CXCL8 release, induced by AA and TNF-α alone, but not in combination. Synergistic CXCL8 release, following AA and TNF-α challenge, was not medicated via a single signaling pathway (MEK1, JNK, phosphoinositide 3-kinase, and NF-κB) nor by hyperactivation of NF-κB or p38. To investigate if these findings occur in other airway cells, effects of AA in primary human airway smooth muscle (ASM) cells and human bronchial epithelial cells were also investigated. We found proinflammatory effects in ASM cells but not epithelial cells. This study suggests that diets rich in ω-6 PUFAs might promote airway inflammation via multiple pathways, including COX-dependent and -independent pathways, and in an obese person, may lead to more severe airway inflammation.

An Official American Thoracic Society Workshop Report: Evaluation and Management of Asthma in the Elderly

Asthma in the elderly (>65 yr old) is common and associated with higher morbidity and mortality than asthma in younger patients. The poor outcomes in this group are due, in part, to underdiagnosis and undertreatment. There are a variety of factors related to aging itself that affect the presentation of asthma in the elderly and influence diagnosis and management. Structural changes in the aging lung superimposed on structural changes due to asthma itself can worsen the disease and physiologic function. Changes in the aging immune system influence the cellular composition and function in asthmatic airways. These processes and differences from younger individuals with asthma are not well understood. Phenotypes of asthma in the elderly have not been clearly delineated, but it is likely that age of onset and overlap with chronic obstructive pulmonary disease impact disease characteristics. Physiologic tests and biomarkers used to diagnose and follow asthma in the elderly are generally similar to testing in younger individuals; however, whether they should be modified in aging has not been established. Confounding influences, such as comorbidities (increasing the risk of polypharmacy), impaired cognition and motor skills, psychosocial effects of aging, and age-related adverse effects of medications, impact both diagnosis and treatment of asthma in the elderly. Future efforts to understand asthma in the elderly must include geriatric-specific methodology to diagnose, characterize, monitor, and treat their disease.

Race is associated with differences in airway inflammation in patients with asthma

BACKGROUND

African American subjects have a greater burden from asthma compared with white subjects. Whether the pattern of airway inflammation differs between African American and white subjects is unclear.

OBJECTIVE

We sought to compare sputum airway inflammatory phenotypes of African American and white subjects treated or not with inhaled corticosteroids (ICSs; ICS+ and ICS-, respectively).

METHODS

We performed a secondary analysis of self-identified African American and white subjects with asthma enrolled in clinical trials conducted by the National Heart, Lung, and Blood Institute-sponsored Asthma Clinical Research Network and AsthmaNet. Demographics, clinical characteristics, and sputum cytology after sputum induction were examined. We used a sputum eosinophil 2% cut point to define subjects with either an eosinophilic (≥2%) or noneosinophilic (<2%) inflammatory phenotype.

RESULTS

Among 1018 participants, African American subjects (n = 264) had a lower FEV1 percent predicted (80% vs 85%, P < .01), greater total IgE levels (197 vs 120 IU/mL, P < .01), and a greater proportion with uncontrolled asthma (43% vs 28%, P < .01) compared with white subjects (n = 754). There were 922 subjects in the ICS+ group (248 African American and 674 white subjects) and 298 subjects in the ICS- group (49 African American and 249 white subjects). Eosinophilic airway inflammation was not significantly different between African American and white subjects in either group (percentage with eosinophilic phenotype: ICS+ group: 19% vs 16%, P = .28; ICS- group: 39% vs 35%, P = .65; respectively). However, when adjusted for confounding factors, African American subjects were more likely to exhibit eosinophilic airway inflammation than white subjects in the ICS+ group (odds ratio, 1.58; 95% CI, 1.01-2.48; P = .046) but not in the ICS- group (P = .984).

CONCLUSION

African American subjects exhibit greater eosinophilic airway inflammation, which might explain the greater asthma burden in this population.

Mouse Modeling of Obese Lung Disease. Insights and Caveats

As the obesity epidemic has worsened, its impact on lung health and disease has become progressively evident. The interactions between obesity and the accompanying metabolic syndrome and diseases such as asthma, pneumonia, and acute respiratory distress syndrome (ARDS) have proven complex and often counterintuitive in human studies. Hence, there is a growing need for relevant experimental approaches to understand the interactions between obesity and the lung. To this end, researchers have increasingly exploited mouse models combining both obesity and lung diseases, including ARDS, pneumonia, and asthma. Such models have both complemented and advanced the understanding we have gained from clinical studies and have allowed elegant dissections of obesity's effects on the pathogenesis of lung disease. Yet these models come with several critically important caveats that we must reflect on when interpreting their results.

Obesity promotes prolonged ovalbumin-induced airway inflammation modulating T helper type 1 (Th1), Th2 and Th17 immune responses in BALB/c mice

Clinical and epidemiological studies indicate that obesity affects the development and phenotype of asthma by inducing inflammatory mechanisms in addition to eosinophilic inflammation. The aim of this study was to assess the effect of obesity on allergic airway inflammation and T helper type 2 (Th2) immune responses using an experimental model of asthma in BALB/c mice. Mice fed a high-fat diet (HFD) for 10 weeks were sensitized and challenged with ovalbumin (OVA), and analyses were performed at 24 and 48 h after the last OVA challenge. Obesity induced an increase of inducible nitric oxide synthase (iNOS)-expressing macrophages and neutrophils which peaked at 48 h after the last OVA challenge, and was associated with higher levels of interleukin (IL)-4, IL-9, IL-17A, leptin and interferon (IFN)-γ in the lungs. Higher goblet cell hyperplasia was associated with elevated mast cell influx into the lungs and trachea in the obese allergic mice. In contrast, early eosinophil influx and lower levels of IL-25, thymic stromal lymphopoietin (TSLP), CCL11 and OVA-specific immunoglobulin (IgE) were observed in the obese allergic mice in comparison to non-obese allergic mice. Moreover, obese mice showed higher numbers of mast cells regardless of OVA challenge. These results indicate that obesity affects allergic airway inflammation through mechanisms involving mast cell influx and the release of TSLP and IL-25, which favoured a delayed immune response with an exacerbated Th1, Th2 and Th17 profile. In this scenario, an intense mixed inflammatory granulocyte influx, classically activated macrophage accumulation and intense mucus production may contribute to a refractory therapeutic response and exacerbate asthma severity.

Interacting effects of obesity, race, ethnicity and sex on the incidence and control of adult-onset asthma

Background

To improve care and control for patients with adult-onset asthma, a better understanding of determinants of their risk and outcomes is important. We investigated how associations between asthma, asthma control and obesity may be modified by patient demographic characteristics.

Methods

This retrospective study of adults enrolled in several health plans across the U.S. (n = 2,860,305) examined the interacting effects of obesity, age, race, and sex on adult-onset asthma and asthma control. Multivariable adjusted Cox and logistic regression models estimated hazard ratios (HR), and 95 % confidence intervals (CI) for the associations between body mass index (BMI) and study outcomes, and interactions of BMI with demographic characteristics.

Results

Compared with individuals who had a BMI <25 kg/m², the hazard of adult-onset asthma progressively increased with increasing BMI, from a 12 % increase among persons with a BMI of 25.0–29.9 kg/m² (HR 1.12, 95 % CI 1.10, 1.14) to an almost 250 % increase among persons with a BMI ≥50 kg/m² (HR 2.49, 95 % CI 2.38, 2.60). The magnitude of the association between obesity and asthma risk was greater for women (compared with men) and lower for Blacks (compared with non-Hispanic Whites). Among individuals with asthma, obesity was associated with poorly controlled and high-risk asthma.

Conclusions

The present study demonstrates that the magnitude of the associations between obesity and adult-onset asthma incidence and control are modified by race, age, and sex. Understanding the role of obesity in the development of adult-onset asthma will help to improve asthma treatment algorithms and to develop targeted interventions.

Uncontrolled asthma and its risk factors in adult Chinese asthma patients

Background:

Asthma affects a large number of patients in China, but relatively little is known about asthma management among Chinese patients. This study aims to estimate asthma control rate among adult Chinese patients and to identify predictors associated with uncontrolled asthma.

Methods:

A total of 4125 asthma patients aged ⩾17 years and representing all regions of mainland China except Tibet were surveyed. Asthma control status was assessed using the Asthma Control Test (ACT) and classified as controlled (ACT score ⩾ 20) and uncontrolled (ACT score ⩽ 19). A multivariate logistic regression model was used to identify predictors associated with uncontrolled asthma from the factors including demographics, rhinitis, allergic rhinitis, and treatment adherence.

Results:

Asthma was controlled in 44.9%, and uncontrolled in 55.1% of the study participants. High rates of uncontrolled asthma were found in patients with treatment nonadherence (77.3%), poor adherence (66.2%), no schooling (64.8%), or obesity (62.9%). The risk of uncontrolled asthma was much higher in the treatment nonadherence group than the complete adherence group [odds ratio (OR) = 4.55 (3.68–5.62), p < 0.001]. Other predictors for uncontrolled asthma included concomitant rhinitis [OR = 1.31 (1.14–1.50), p < 0.001], obesity [OR = 1.31 (1.05–1.64), p = 0.019], asthma duration > 3 years [OR = 1.22 (1.07–1.39), p = 0.004] and age ⩾ 45 years [OR = 1.23 (1.07–1.41), p = 0.004].

Conclusions:

About half of the participants in this study had uncontrolled asthma. Treatment nonadherence is one of the significant predictors, which is very strongly associated with uncontrolled asthma. Efforts should be prioritized to promote patients’ treatment adherence to improve asthma control while attention is needed on rhinitis or obesity.

Factors associated with increased healthcare utilization among adults with asthma

OBJECTIVE

To evaluate determinants of increased emergency room (ER) visit and hospitalization among adults with asthma, with emphasis on the role of psychological distress, self-efficacy, and obesity.

METHODS

For analysis 2009, 2011/2012 California Health Interview Survey was used. Adults who reported lifetime asthma were selected. Association between ER and overnight hospital stay with population characteristics were conducted using chi-square analysis. Multivariable binary logistic regression models, taking into account control variables, were utilized to assess the relationship between ER visit or overnight hospital stay with that of psychological distress, self-efficacy, and obesity.

RESULTS

Odds of ER visits were higher among those with mild-to-moderate psychological distress (adjusted odds ratio [aOR] = 1.94, 95% CI: 1.28, 2.94), and among those with serious psychological distress (aOR = 2.62, 95% CI: 1.65, 4.16). Mild-to-moderate distress was associated with two-fold increase in hospital overnight stay (aOR = 2.05, 95% CI: 1.29, 3.25). Adults with asthma who reported low self-efficacy had increased ER visits (aOR = 6.21, 95% CI: 3.63, 10.65) and hospitalization (aOR = 4.13, 95% CI: 2.63, 6.49). Finally, adults who had asthma and were obese had higher odds of ER visits (aOR = 1.60, 95% CI: 1.20, 2.13).

CONCLUSIONS

Healthcare utilization is higher among asthma patients with psychological distress, low self-efficacy, and obesity. Interventions, such as incorporation of integrated care models, are critical to ensure early screening of mental health status among such patients. In addition, there is a need for patient education and improved weight management among adults with asthma.

Obesity: systemic and pulmonary complications, biochemical abnormalities, and impairment of lung function

Obesity is currently one of the major epidemics of this millennium and affects individuals throughout the world. It causes multiple systemic complications, some of which result in severe impairment of organs and tissues. These complications involve mechanical changes caused by the accumulation of adipose tissue and the numerous cytokines produced by adipocytes. Obesity also significantly interferes with respiratory function by decreasing lung volume, particularly the expiratory reserve volume and functional residual capacity. Because of the ineffectiveness of the respiratory muscles, strength and resistance may be reduced. All these factors lead to inspiratory overload, which increases respiratory effort, oxygen consumption, and respiratory energy expenditure. It is noteworthy that patterns of body fat distribution significantly influence the function of the respiratory system, likely via the direct mechanical effect of fat accumulation in the chest and abdominal regions. Weight loss caused by various types of treatment, including low-calorie diet, intragastric balloon, and bariatric surgery, significantly improves lung function and metabolic syndrome and reduces body mass index. Despite advances in the knowledge of pulmonary and systemic complications associated with obesity, longitudinal randomized studies are needed to assess the impact of weight loss on metabolic syndrome and lung function.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Clinical characteristics of asthmatic patients with influenza-like illness and risk of severe exacerbations in Mexico

BACKGROUND

Patients with chronic inflammatory lung diseases, such as asthma, are at higher risk for influenza-like illness (ILI) complications. Viral infections are known to trigger asthma exacerbations, but a thorough description of the clinical characteristics of ILI-associated asthma exacerbations and the role of viruses as a risk factor for severe exacerbation (SE) in ILI has not been published yet.

OBJECTIVE

To investigate risk factors for SE in patients with ILI and asthma.

METHODS

Patients with ILI symptoms were recruited from 6 hospitals of Mexico (LaRed sites) during 2010 to 2014. Those with a previous asthma diagnosis and ILI symptoms and who were 5 years or older were included. Patients were assigned as cases or controls based on symptoms reported. SE was defined when participants presented with wheezing or dyspnea and required hospitalization.

RESULTS

A total of 486 patients with ILI and a diagnosis of asthma were included. There were no differences in the proportion, number, or type of viral illness among those with and without SE. Those with SE were less likely to report ILI symptoms. Muscle pain and nasal drip were predictors for patients not progressing to SE. A delay in seeking medical care was associated with SE (odds ratio, 2.93; 95% CI, 1.46-5.88).

CONCLUSION

The presence of a particular virus did not predict SE. ILI symptoms in asthma patients are not associated with severe exacerbation. Patients with asthma should be encouraged to seek early medical care when ILI symptoms are first noticed to prevent serious complications.

Emerging Comorbidities in Adult Asthma: Risks, Clinical Associations, and Mechanisms

Asthma is a heterogeneous disease with many phenotypes, and age at disease onset is an important factor in separating the phenotypes. Most studies with asthma have been performed in patients being otherwise healthy. However, in real life, comorbid diseases are very common in adult patients. We review here the emerging comorbid conditions to asthma such as obesity, metabolic syndrome, diabetes mellitus type 2 (DM2), and cardiac and psychiatric diseases. Their role as risk factors for incident asthma and whether they affect clinical asthma are evaluated. Obesity, independently or as a part of metabolic syndrome, DM2, and depression are risk factors for incident asthma. In contrast, the effects of comorbidities on clinical asthma are less well-known and mostly studies are lacking. Cross-sectional studies in obese asthmatics suggest that they may have less well controlled asthma and worse lung function. However, no long-term clinical follow-up studies with these comorbidities and asthma were identified. These emerging comorbidities often occur in the same multimorbid adult patient and may have in common metabolic pathways and inflammatory or other alterations such as early life exposures, systemic inflammation, inflammasome, adipokines, hyperglycemia, hyperinsulinemia, lung mechanics, mitochondrial dysfunction, disturbed nitric oxide metabolism, and leukotrienes.

Diagnosis and investigation in the severe asthma clinic

Severe asthma is recognised as an important and emerging area of unmet need in asthma. The assessment of severe asthma should include three steps; (1) determining the diagnosis of asthma, including verification that the disease is severe asthma, (2) assessing comorbidities and contributing factors that will impact on clinical severity, as well as (3) assessing asthma phenotypes. These steps recognize the importance of heterogeneity in asthma as a key factor that determines the disease course and increasingly the choice of successful therapy. This assessment should be undertaken systematically and is best done by an expert multidisciplinary team. Here, we will outline the important aspects that should be included in the clinical assessment of the patient in the severe asthma clinic, including diagnosis, clinical history, the assessment of important comorbidities and the key investigations needed to support them.

Asthma and obesity: is weight reduction the key to achieve asthma control?

PURPOSE OF REVIEW

Obesity has significant negative impact on asthma control and risk of exacerbations. The purpose of this review is to discuss recent studies evaluating the effects of weight reduction on asthma control in obese adults.

RECENT FINDINGS

Clinical studies have shown that weight reduction in obese patients is associated with improvements in symptoms, use of controller medication, and asthma-related quality of life together with a reduction in the risk for severe exacerbations. Furthermore, several studies have also revealed improvements in lung function and airway responsiveness, and more recently it has been shown that weight reduction following bariatric surgery has positive impact on small airway function, systemic inflammation and bronchial inflammation in this group of patients, which may explain the observed improvements in symptom control and lung function.

SUMMARY

Weight reduction in obese adults with asthma leads to an overall improvement in asthma control, including airway hyperresponsiveness and inflammation. Weight reduction should be a cornerstone in the management of obese patients with asthma.

Patterns, predictors and outcomes of asthma control and exacerbations during pregnancy: a prospective cohort study

There exists a paucity of data for socially disadvantaged populations describing patterns and predictors of asthma control status and exacerbations during pregnancy, and their relationship to adverse perinatal outcomes.

Asthmatic women (n=189) were followed prospectively during pregnancy, with visits at 12, 20, 28 and 36 weeks gestation. Data on loss of control, recurrent uncontrolled asthma and moderate/severe exacerbations were collected at each visit and their relationship to perinatal outcomes examined following stratification for fetal sex.

50% of asthmatic women experienced a loss of control or moderate/severe exacerbation during pregnancy, with 22% of women experiencing a moderate/severe exacerbation. Factors associated with an increased risk of women experiencing recurrent uncontrolled asthma during pregnancy included smoking (relative risk 2.92, 95% CI 1.53–5.58), inhaled corticosteroid use at the beginning of pregnancy (relative risk 2.40, 95% CI 1.25–4.60) and increasing maternal age (relative risk 1.06, 95% CI 1.01–1.11). No factors were associated with moderate/severe exacerbations. Asthma control rather than exacerbations during pregnancy appeared to be most strongly correlated with perinatal outcomes. Following stratification by fetal sex, the presence of recurrent uncontrolled asthma was associated with an increased risk of being small for gestational age in women pregnant with females (33.3% versus 9.5%; p=0.018). In contrast, there was a nonsignificant increased risk of preterm birth in women with recurrent uncontrolled asthma that were pregnant with males (25.0% versus 11.8%; p=0.201)

These results suggest that the key to improving perinatal outcomes lies in improving asthma control as early as possible in pregnancy and monitoring throughout pregnancy, rather than focusing on preventing exacerbations alone.

Recurrent uncontrolled asthma during gestation is a greater contributor to poor perinatal outcomes than exacerbationshttp://ow.ly/X0OSa

Asthma symptoms in obese adults: The challenge of achieving asthma control

The association between asthma and obesity is well-described, but not straightforward, and according to current guidelines asthma control is more difficult to achieve in obese patients. The currently available studies evaluating response to pharmacological asthma therapy in obese patients show that these patients have an altered, in general less favorable, response to both reliever and controller medication compared to normal weight patients. However, at present, the limited available evidence precludes evidence-based recommendations. The 'obesity-related asthma' phenotype has different characteristics, including association with atopy and type of airway inflammation, compared to 'classic' asthma. Furthermore, weight loss in patients with this phenotype leads to an improvement in symptoms, lung function, and airway responsiveness, as well as a reduction in medication utilization and hospital admissions. Obese patients, who present with symptoms suggesting a diagnosis of asthma, may have a distinct phenotype or a disease mimicking asthma, likely to have a potentially higher remission rate. And by that, our approach to this group of patients should combine pharmacologic and non-pharmacologic therapies, including exercise, weight loss and dietary interventions, instead of primarily focusing on disease control by stepping up asthma therapy.