Impact of Abdominal Visceral Adiposity on Adult Asthma Symptoms

Lower skeletal muscle density and airway structure on computed tomography in asthma

BACKGROUND

Lower skeletal muscle density may reflect muscle adiposity and metabolic dysregulation that potentially impair disease control and lung function independent of high body mass index (BMI) in patients with asthma.

OBJECTIVE

To investigate whether the lower density of pectoralis muscles (PMs) and erector spinae muscles (ESMs) on chest computed tomography was associated with airway structural changes in patients with asthma.

METHODS

Consecutive patients with asthma and healthy controls undergoing chest computed tomography were retrospectively analyzed. The ESM and PM density, areas of subcutaneous adipose tissue near the PM and epicardial adipose tissue, wall area percent of the airways, and airway fractal dimension (AFD) were quantified on computed tomography.

RESULTS

The study included 179 patients with asthma (52% women) and 88 controls (47% women). All the controls were 60 years old or younger. The PM and ESM density in female patients with asthma who were 60 years old or younger were significantly lower than those in controls after adjustment for BMI. In female patients with asthma at all ages, lower PM and ESM density (but not subcutaneous or epicardial adipose tissue area) was associated with greater wall area percent of the airways and lower AFD after adjusting for age, height, BMI, smoking status, blood eosinophil count, and oral corticosteroid use. The only association between ESM density and AFD was found in male patients with asthma.

CONCLUSION

Lower skeletal muscle density may be associated with airway wall thickening and less complexity of the airway luminal tree in female patients with asthma.

Association between visceral adipose tissue and asthma based on the NHANES and Mendelian randomization study

BACKGROUND

Obesity is a crucial risk factor for asthma. Observational studies have examined the association between abdominal obesity and asthma symptoms. This study aimed to investigate the causal relationship between visceral adipose tissue (VAT) and asthma and its potential as an independent indicator.

METHODS

This study utilized data from the National Health and Nutrition Examination Survey spanning 2011-8. Multivariable logistic regression and stratified variable selection were employed to identify associations between asthma and VAT. Moreover, a two-sample Mendelian randomization analysis, using 221 genetic variants as instrumental variables, was conducted to assess this relationship further.

RESULTS

Our findings indicated that individuals with higher VAT levels were more likely to develop asthma. Visceral obesity remained a significant risk factor for asthma after adjusting for demographic characteristics. Genetic predictions suggest a positive association between VAT and an elevated risk of asthma (odds ratio [OR] = 1.393, 95% confidence interval [CI]: 1.266-1.534, and P = 1.43E-11). No significant polymorphisms were detected using the Mendelian randomization-Egger intercept test.

CONCLUSIONS

This study presents potential evidence supporting the causal role of VAT in asthma development. Furthermore, the findings from the Mendelian randomization analysis further reinforce the relationship between VAT and asthma risk.

Increased adiposity-to-muscle ratio and severity of sinusitis affect quality of life in asthma: Computed tomographic analysis

Background

Deteriorated sinusitis and increased adiposity relative to muscle mass may affect quality of life in patients with asthma. However, whether these effects are observed regardless of intrapulmonary pathology is unknown.

Objectives

We evaluated the correlation of the cross-sectional ratio of abdominal visceral fat (VF) to erector spinae muscle (ESM) and sinus findings based on Lund-Mackey scoring system (LMS) on computed tomography (CT) with the impaired score of the Asthma Quality of Life Questionnaire (AQLQ), regardless of airway and parenchymal disease, in patients with asthma.

Methods

We recruited participants from the Hokkaido-based severe asthma cohort who had completed AQLQ and CT examination at the entry. The participants were divided into high (highest) and low (other quartiles) groups on the bases of the extrapulmonary indices. Multivariate analysis examined the association of VF/ESM for the adiposity-to-muscle ratio and LMS with AQLQ after adjusting for the airway fractal dimension for airway index and percentage of low attenuation volume to lung volume for parenchymal index.

Results

No significant differences were observed in VF/ESM and LMS in terms of sex. The AQLQ score in the high VF/ESM group and high LMS group was lower than those in low VF/ESM group and low LMS group (63 male and 100 female subjects). High VF/ESM (estimate [95% confidence interval] (-0.43 [-0.61, -0.25]) and high LMS scores (-0.22 [-0.41, -0.03]) were associated with low AQLQ scores when adjusted for age, body mass index, smoking status, blood eosinophil count, and intrapulmonary CT indices.

Conclusions

Increased VF relative to ESM mass and high LMS may deteriorate asthma-related quality of life, regardless of presence of intrapulmonary disease.

Weight-adjusted waist index is an independent predictor of all-cause and cause-specific mortality in patients with asthma

BACKGROUND

There is a close relationship between obesity and the occurrence of asthma.The weight-adjusted waist index (WWI) is a relatively novel anthropometric parameter that reflects obesity.

OBJECTIVE

We aimed to explore the association between WWI and mortality in the asthma population.

METHODS

We included adult with asthma from NHANES 1999-2018. WWI = Waist circumference (cm)/square root of body weight (kg). Current asthma was determined by the participant's responses in standardized questionnaires. All-cause, cardiovascular disease (CVD), cancer, and respiratory disease mortality information was obtained by prospectively matching these data to the National Death Index. Multivariate-adjusted Cox proportional hazards regression analyses, Kaplan Meier survival analyses, restricted cubic spline (RCS) analyses, stratified analyses, and sensitivity analyses were used to clarify these associations.

RESULTS

A total of 101,316 participants were included in the study, and 3223 were diagnosed with asthma.WWI was independently and positively associated with all-cause and all factor-specific mortality in asthma. In fully adjusted models, each unit increase in WWI was associated with 43 % (hazard ratio [HR] and 95 % confidence interval [CI] = 1.43 [1.25,1.64], p < 0.0001), 58 % (1.58 [1.25, 1.99], p < 0.001), 50 % (1.50 [1.19, 1.90], p < 0.001), and 79 % (1.79 [1.34, 2.39], p < 0.0001) increased all-cause, CVD, cancer, and respiratory disease mortality, respectively. RCS analyses showed largely linear associations between WWI and all mortality risks. Stratified analyses indicated that these associations were influenced by multiple factors, and that age was consistently the effect modifier across all associations.

CONCLUSIONS

WWI is an independent predictor of all-cause, CVD, cancer, and respiratory-related mortality in the adult asthma population. These findings highlight that WWI may have novel prognostic value as a simple and easily accessible obesity parameter in asthma patients.

Impact of obesity in asthma: Possible future therapies

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

A prospective study to assess the impact of a novel CFTR therapy combination on body composition in patients with cystic fibrosis with F508del mutation

BACKGROUND & AIM

Malnutrition is a prevalent condition in Cystic Fibrosis (CF) and can result in worsening of pulmonary function and other comorbidities. Cystic fibrosis transmembrane regulator (CFTR) modulator therapies are improving the CF-related care and outcomes. Body Mass Index (BMI) is the most commonly used parameter to assess nutritional status, albeit it is a very unspecific indicator. Hence, current guidelines recommend body composition analysis as a part of nutritional assessment. The aim of our study was to evaluate the impact of elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA) treatment on body composition and respiratory function.

METHODS

We recruited patients with CF from University Hospital La Princesa, with follow-up in the Adult Cystic Fibrosis Unit. All patients were eligible to initiate ELX/TEZ/IVA therapy. Body composition was assessed with a Bioelectrical Impedance Analysis (BIA) and spirometry data were obtained before and after 6 months of treatment.

RESULTS

Our study sample was composed of 36 patients with CF. We observed a significant increase in BMI after 6 months of treatment (p < 0.001), as well as an increase in fat mass (p = 0.008) and visceral fat area (p = 0.026). The other body composition parameters did not yield significant changes. Overall, %FEV1 increased from 72.67 % (±17.39) to 84.74 % (±18.18) after 6 months of treatment. Interestingly, we found an inverse correlation between %FEV1 and fat mass (r = -0,476; p = 0,0058), %FEV1 and age (r = -0,411; p = 0,0196) and between %FEV1 and visceral fat area (r = -0,515; p = 0,0025). On the contrary, we found a direct correlation between %FEV1 and body cell mass (r = 0,367; p = 0,038).

CONCLUSIONS

Novel CFTR modulators are emerging for the treatment of CF. Specifically, triple combination with ELX/TEZ/IVA has shown to effectively improve both pulmonary and nutritional status in patients with CF with F508del mutation. Body composition should be a part of the routine assessment for patients with CF.

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.

Physical Health-Related Quality of Life in Relation to Mediterranean Diet Adherence in a Sample of Greek Asthma Patients: A Pilot Study

The role of nutrition in the management of asthma in obese patients is of increasing interest due to their limited response to inhaled corticosteroids. Some studies note that through diet and lifestyle, there can be an improvement in asthma control. The aim of the present study was to investigate the adherence to the Mediterranean Diet and its association with asthma severity and quality of life in patients with bronchial asthma. This is a cross-sectional study of 85 patients (70.6% female), with a mean age of 57 years, from the General University Hospital of Larissa and, more specifically, patients of the outpatient asthma clinic. Data were collected with the use of specific questionnaires. In relation to BMI, 12.9% of participants were of a normal weight, 45.9% were overweight, 25.9% were obese level I, 5.9% were obese level II, and 9.4% were in the morbidly obese range. Based on the Med Diet Score (ranging from 21 to 35), most participants (85.9%) reported moderate adherence to the Mediterranean Diet. Further analysis examined the correlations of the PCS-12 score with the frequency of consumption of each of the 11 food categories, as well as all demographic and health behavior variables. The ranked correlations indicated a significant relationship between PCS-12 score and Med Diet adherence and the consumption of alcoholic beverages (r = 0.437, p < 0.05), in accordance with the Mediterranean Diet suggestions, as well as a negative relationship with BMI score (r = -0.454, p < 0.010). Moreover, significant correlations were also present between the physical quality of life and AQLQ score and work type, as well as gender, age, and marital status. The results of our study showed a high rate of obesity in patients with asthma at the General University Hospital of Larissa and moderate adherence to the Mediterranean Diet. Increased BMI and alcoholic beverage consumption in asthma patients were significant predictors of lower physical health-related quality of life. In conclusion, personal and society-level interventions are required to effectively address obesity and poor diet in patients with asthma.

Clinical characteristics and natural course of chronic obstructive pulmonary disease and/or asthma in Japanese patients: a summary report of two Hokkaido-based cohort studies

Chronic obstructive pulmonary disease (COPD) and asthma are the most common chronic airway diseases and are characterized by chronic airway inflammation and airflow limitation. Japanese patients with COPD or asthma have characteristics different from those of Westerners. Therefore, understanding the characteristics and clinical course of Japanese patients with COPD and those with asthma, particularly severe asthma, is critical for their management and appropriate treatment. The Hokkaido COPD cohort and Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) are high-quality cohort studies of COPD and asthma in the Japanese population and provide valuable data. This report summarizes the clinical findings from the two cohort studies and provides data for more appropriate management of Japanese patients with COPD and/or asthma. Overall, 279 patients with COPD were followed up for up to 10 years in the Hokkaido COPD cohort study, and 127 with severe asthma were followed up for up to 6 years in the Hi-CARAT study. Seventy-nine patients with mild-to-moderate asthma provided baseline data for the Hi-CARAT study. In each disease, several distinct factors, including systemic status and non-pulmonary factors, were associated with important clinical outcomes, such as lung function decline, exacerbations, impaired quality of life, and mortality. Therefore, multifaceted evaluation based on the characteristics of the Japanese population is necessary for the management of COPD and asthma.

Association between abdominal and general obesity and respiratory symptoms, asthma and COPD. Results from the RHINE study

INTRODUCTION

Previous studies on the association between abdominal and general obesity and respiratory disease have provided conflicting results.

AIMS AND OBJECTIVES

We aimed to explore the associations of abdominal obesity with respiratory symptoms, asthma, and chronic obstructive pulmonary disease independently from general obesity in women and men.

METHODS

This cross-sectional study was based on the Respiratory Health in Northern Europe (RHINE) III questionnaire (n = 12 290) conducted in 2010-2012. Abdominal obesity was self-measured waist circumference using a sex-specific standard cut-off point: ≥102 cm in males and ≥88 cm in females. General obesity was defined as self-reported BMI ≥30.0 kg/m².

RESULTS

There were 4261 subjects (63% women) with abdominal obesity and 1837 subjects (50% women) with general obesity. Both abdominal and general obesity was independent of each other and associated with respiratory symptoms (odds ratio (OR) from 1.25 to 2.00)). Asthma was significantly associated with abdominal and general obesity in women, OR (95% CI) 1.56 (1.30-1.87) and 1.95 (1.56-2.43), respectively, but not in men, OR 1.22 (0.97-3.17) and 1.28 (0.97-1.68) respectively. A similar sex difference was found for self-reported chronic obstructive pulmonary disease.

CONCLUSIONS

General and abdominal obesity were independent factors associated with respiratory symptoms in adults. Asthma and chronic obstructive pulmonary disease were independently linked to abdominal and general obesity in women but not men.

Association of general and abdominal obesity with lung function, FeNO, and blood eosinophils in adult asthmatics: Findings from NHANES 2007-2012

Purpose: Obesity is considered a risk factor for asthma exacerbation. However, limited studies have focused on the association of different levels of weight clusters with asthma. As such, we study the associations between different weight clusters with FeNO, blood eosinophils, and lung function among adult asthmatics. Methods: Data from 789 participants aged 20 years or older in the National Health and Nutrition Examination Survey 2007-2012 were analyzed. Body mass index (BMI) and waist circumference (WC) were used to determine the weight status. The study population was divided into five groups, including normal weight and low WC (153), normal weight and high WC (43), overweight and high WC (67), overweight and abdominal obesity (128), and general and abdominal obesity (398). A Multivariate linear regression model was used to evaluate the abovementioned associations after adjusting for potential confounding factors. Results: The adjusted models showed that general and abdominal obesity cluster (adjusted β = -0.63, 95% confidence interval (CI): -1.08, -0.17 p < 0.01), and the normal weight with high WC cluster (adjusted β = -0.96, 95% CI: -1.74, -0.19 p < 0.05) were associated with lower levels of blood eosinophils percentage than normal weight and low WC cluster. A similar tendency was shown in the levels of FeNO, but the differences were not significant (p > 0.05). Furthermore, abdominal obesity clusters were significantly associated with lower FVC, FVC% predicted, and FEV₁ measures than normal weight and low WC cluster, especially those individuals with general and abdominal obesity cluster. No association was found between different weight clusters and FEV₁/FVCF ratio. The two other weight clusters did not show the association with any of the lung function measures. Conclusion: General and abdominal obesity were associated with lung function impairment and a significant reduction of FeNO and blood eosinophil percentage. This study emphasized the importance of concurrent determination of BMI and WC in asthma clinical practice.

Association of serum CC16 levels with eosinophilic inflammation and respiratory dysfunction in severe asthma

BACKGROUND

There are knowledge gaps in the potential role of Club cell 16-kDa secretory protein (CC16) in severe asthma phenotypes and type 2 inflammation, as well as the longitudinal effect of CC16 on pulmonary function tests and exacerbation risk in epidemiological studies.

OBJECTIVE AND METHODS

To assess whether serum CC16 is associated with eosinophilic inflammation in patients with severe asthma. We also examined the effect of this protein on the annual decline in forced expiratory volume in the first second (FEV₁) and the risk of exacerbation using a longitudinal approach. We recruited 127 patients with severe asthma from 30 hospitals/pulmonary clinics in Hokkaido, Japan. The least square means and standard error were calculated for T-helper 2 (Th2) biomarkers and pulmonary function test across CC16 tertiles at baseline. We did the same for asthma exacerbation and annual decline in FEV₁ with 3 and 5 years' follow-up, respectively.

RESULTS

We found that serum CC16 was inversely associated with sputum eosinophils and blood periostin in a dose-response manner. Baseline CC16 and FEV₁/forced vital capacity ratio were positively associated in adjusted models (p for trend = 0.008). Patients with the lowest tertile of serum CC16 levels at baseline had a -14.3 mL decline in FEV₁ than those with the highest tertile over 5 years of follow-up (p for trend = 0.031, fully adjusted model). We did not find any association of CC16 with exacerbation risk.

CONCLUSION

Patients with severe asthma with lower circulatory CC16 had enhanced eosinophilic inflammation with rapid FEV₁ decline over time.

The Relationship Between General and Abdominal Obesity, Nutrition and Respiratory Functions in Adult Asthmatics

Objective: Although obesity is known to have adverse effects on asthma, it is not fully known whether general or abdominal obesity affects asthma symptoms more. In this study, the effects of diet and general/abdominal obesity on respiratory functions were evaluated.Methods: A total of 204 adult asthmatic individuals participated in the study. Anthropometric measurements, respiratory functions, asthma control test (ACT) scores, and 24-hour food consumption were recorded. The results were compared according to body mass index (BMI), waist circumference (WC), and waist-hip ratio (WHR) classification.Results: FEV₁, FVC, MEF_25-75, MEF₅₀, and MEF₂₅ decreased with the increase in BMI, WC, and WHR. FEV₁ showed a negative linear relationship with BMI, WC and WHR and these results were more significant in WC and WHR than BMI. Similarly, the ACT score also showed a negative correlation with BMI (r = -0.372; p = 0.023), WC (r = -0.402; p = 0.001) and WHR (r = -0.387; p = 0.011), and the results were more significant in WC and WHR than BMI. Individuals whose WC (OR: 2.170 CI (1.325-3.182)) and WHR (OR: 2.119 CI (1.246-3.338)) were at risk had higher odds of uncontrolled asthma than those with normal WC and WHR. Each 100-kcal increase in total energy consumption increased the odds of uncontrolled asthma (OR: 1.125 CI (1.086-2.217)) (p < 0.05).Conclusions: The effects of WC and WHR, which are indicators of abdominal obesity, on respiratory functions and ACT score were found to be higher than BMI. Obese individuals should be referred to diet clinics to improve their asthma symptoms.

Effects of obesity on CC16 and their potential role in overweight/obese asthma

Introduction

Club cell secretory protein-16 (CC16) is a major anti-inflammatory protein expressed in the airway; however, the potential role of CC16 on overweight/obese asthma has not been assessed. In this study, we examined whether obesity reduces airway/circulatory CC16 levels using experimental and epidemiological studies. Then, we explored the mediatory role of CC16 in the relationship of overweight/obesity with clinical asthma measures.

Methods

Circulating CC16 levels were assessed by ELISA in three independent human populations, including two groups of healthy and general populations and asthma patients. The percentage of cells expressing club markers in obese vs. non-obese mice and human airways was determined by immunohistochemistry. A causal mediation analysis was conducted to determine whether circulatory CC16 acted as a mediator between overweight/obesity and clinical asthma measures.

Results

BMI was significantly and monotonously associated with reduced circulating CC16 levels in all populations. The percentage of CC16-expressing cells was reduced in the small airways of both mice and humans with obesity. Finally, mediation analysis revealed significant contributions of circulatory CC16 in the association between BMI and clinical asthma measures; 21.8% of its total effect in BMI’s association with airway hyperresponsiveness of healthy subjects (p = 0.09), 26.4% with asthma severity (p = 0.030), and 23% with the required dose of inhaled corticosteroid (p = 0.042). In logistic regression analysis, 1-SD decrease in serum CC16 levels of asthma patients was associated with 87% increased odds for high dose ICS requirement (p < 0.001).

Conclusions

We demonstrate that airway/circulating CC16, which is inversely associated with BMI, may mediate development and severity in overweight/obese asthma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02038-1.

Association of longitudinal changes in quality of life with comorbidities and exacerbations in patients with severe asthma

BACKGROUND

Quality of life (QoL) assessment is important in the management of severe asthma, and comorbidities and/or exacerbations may affect longitudinal QoL. However, there are few reports on the longitudinal assessment of QoL in patients with asthma over multiple years and its related factors. This study aimed to clarify the relationship of longitudinal changes in QoL with comorbidities and/or exacerbations during a prolonged observation period in patients with severe asthma.

METHODS

A total of 105 subjects who participated in the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) with a six-year follow-up were analyzed. QoL was assessed annually, using the Standardized Asthma Quality of Life Questionnaire, and the subjects were divided into three groups: (1) persistently good QoL, (2) persistently poor QoL, and (3) fluctuating QoL. Assessed comorbidities comprised depression, gastroesophageal reflux disease, and excessive daytime sleepiness (EDS), a key symptom of obstructive sleep apnea.

RESULTS

Of 105 subjects with severe asthma, 53 (50%) were classified in the persistently good QoL group, 10 (10%) in the persistently poor QoL group, and 42 (40%) in the fluctuating QoL group. The persistently poor QoL group was associated with shorter time to hospitalization due to exacerbation and the presence of multiple comorbidities. In addition, the presence of EDS was an independent contributor to the fluctuating QoL group compared to the persistently good QoL group.

CONCLUSIONS

The presence of multiple comorbidities and hospitalization due to exacerbation contribute to longitudinal changes in QoL in patients with severe asthma.

Adipose Tissue Compartments, Inflammation, and Cardiovascular Risk in the Context of Depression

The neurobiological and behavioral underpinnings linking mental disorders, in particular, major depressive disorder (MDD), with cardiovascular disorders are a matter of debate. Recent research focuses on visceral (intra-abdominal and epicardial) adipose tissue and inflammation and their impact on the development of cardiometabolic disorders. Intra-abdominal adipose tissue is defined as an endocrine active fat compartment surrounding inner organs and is associated with type 2 diabetes mellitus, a risk factor for the later development of cardiovascular disorders. Epicardial (pericardial) adipose tissue is a fat compartment surrounding the heart with close proximity to the arteries supporting the heart. Visceral adipose tissue (VAT) is an important source of inflammatory mediators that, in concert with other risk factors, plays a leading role in cardiovascular diseases. In conjunction with the behavioral (physical inactivity, sedentary lifestyle), psychological (adherence problems), and hormonal (dysfunction of the hypothalamus-pituitary-adrenal axis with subsequent hypercortisolism) alterations frequently accompanying MDD, an enhanced risk for cardiovascular disorders results.

Obesity, Inflammation, and Severe Asthma: an Update

Purpose of Review

Obesity-associated difficult asthma continues to be a substantial problem and, despite a move to address treatable traits affecting asthma morbidity and mortality, it remains poorly understood with limited phenotype-specific treatments. The complex association between asthma, obesity, and inflammation is highlighted and recent advances in treatment options explored.

Recent Findings

Obesity negatively impacts asthma outcomes and has a causal link in the pathogenesis of adult-onset asthma. Imbalance in the adipose organ found in obesity favours a pro-inflammatory state both systemically and in airways. Obesity may impact currently available asthma biomarkers, and obesity-associated asthma specific biomarkers are needed. Whilst surgical weight loss interventions are associated with improvements in asthma control and quality of life, evidence for pragmatic conservative options are sparse. Innovative approaches tackling obesity-mediated airway inflammation may provide novel therapies.

Summary

The immunopathological mechanisms underlying obesity-associated asthma require further research that may lead to novel therapeutic options for this disease. However, weight loss appears to be effective in improving asthma in this cohort and focus is also needed on non-surgical treatments applicable in the real-world setting.

The Effects of Asthma on the Association Between Pulmonary Function and Obesity: A 16-Year Longitudinal Study

Background

Asthma and obesity are important public health issues around the world. Obesity is considered a risk factor associated with the severity and incidence of asthma. We investigated the relationships between poor pulmonary function (defined by forced vital capacity (FVC) and percentage of predicted FVC (FVC%)) and obesity.

Methods

This is a retrospective longitudinal study using the MJ health examination database in Taiwan from 2000 to 2015. There were 160,609 participants aged ≥20 years with complete obesity indicators and lung function data, and having at least two visits. A generalized estimation equation (GEE) model was applied to estimate the association between lung function and obesity.

Results

BMI was the best indicator to predict poor pulmonary function for our participants. Results of BMI are presented as an example: Obesity (body mass index (BMI) ≥27.0 kg/m²) is significantly associated with lower FVC [adjusted coefficients (β) for asthmatics: -0.11 L (95% CI: -0.14, -0.08); adjusted β for non-asthmatics: -0.08 L (-0.09, -0.08)] and FVC% [adjusted β for asthmatics: -1.91% (95% CI: -2.64, -1.19); adjusted β for non-asthmatics: 1.48% (-1.63, -1.33)]. Annual change of BMI (ΔBMI/year) is an independent risk factor for decreased FVC [adjusted β for asthmatics: -0.030 L (-0.048, -0.013); adjusted β for non-asthmatics: -0.019 L (-0.022, -0.016)] and FVC% [adjusted β for non-asthmatics: -0.603% (-1.063, -0.142); adjusted β for non-asthmatics: -0.304% (-0.393, -0.214)], and is significantly associated with accelerated FVC decline [adjusted β of ΔFVC/year and ΔFVC %/year for asthmatics: -0.038 L (-0.054, -0.022) and -0.873% (-1.312, -0.435); adjusted β of ΔFVC/year and ΔFVC %/year for non-asthmatics: -0.033 L (-0.042, -0.024) and -0.889% (-1.326, -0.452)].

Conclusion

Obesity is significantly associated with decreased lung function, and asthmatics had a higher risk than non-asthmatics.

Overweight improves long-term survival in Japanese patients with asthma

BACKGROUND

Obesity is a risk factor for severe and difficult-to-treat asthma. However, the impact of different physiques on long-term outcomes is poorly understood. We aimed to investigate the correlation between obesity and asthma-associated long-term mortality in Japanese adults.

METHODS

From the data on 3146 individuals with air pollution-related respiratory diseases in the Omuta City Air Pollution-Related Health Damage Cohort Program, 697 adult patients with asthma were analyzed. Hazard ratios for long-term all-cause and respiratory disease -related mortality were compared in patients with different physiques using the Cox proportional hazard models. The classification of physiques was based on the WHO obesity criteria.

RESULTS

Of the 697 patients, 439 died during the median observation period of 26.3 years. The number (% of total) of underweight, normal-weight, pre-obese, and obese class I-III individuals were 75 (10.8%), 459 (65.9%), 140 (20.1%), and 23 (3.3%), respectively. The Cox proportional hazard model (adjusted hazard ratio [95% confidence interval], P value) showed that pre-obese group had a significantly reduced risk for all-cause (0.65 [0.51 to 0.83], P < 0.05) and respiratory disease (0.55 [0.37 to 0.81], P < 0.05)-related mortality related to normal-weight group.

CONCLUSIONS

Our cohort program demonstrated that being slightly overweight may reduce the risk of long-term mortality in patients with asthma. However, the influence of obesity on long-term outcomes remains unclear in asthma, because of the small number of obese patients included in our study. Our findings suggest that interventions, including nutrition and exercises, should be provided to Japanese patients with asthma.

The Gut/Lung Microbiome Axis in Obesity, Asthma, and Bariatric Surgery: A Literature Review

Mounting evidence suggests that obesity, parameters of metabolic syndrome, and asthma are significantly associated. Interestingly, these conditions are also associated with microbiome dysbiosis, notably in the airway microbiome for patients with asthma and in the gut microbiome for patients with obesity and/or metabolic syndrome. Considering that improvements in asthma control, lung function, and airway hyperresponsiveness are often reported after bariatric surgery, this review investigated the potential role of bacterial gut and airway microbiome changes after bariatric surgery in ameliorating asthma symptoms. Rapid and persistent gut microbiota alterations were reported following surgery, some of which can be sustained for years. The gut microbiome is thought to modulate airway cellular responses via short-chain fatty acids and inflammatory mediators, such that increased propionate and butyrate levels following surgery may aid in reducing asthma symptoms. In addition, increased prevalence of Akkermansia muciniphila after Roux-en-Y gastric bypass and sleeve gastrectomy may confer protection against airway hyperreactivity and inflammation. Metabolic syndrome parameters also improved following bariatric surgery, and whether weight-loss-independent metabolic changes affect airway processes and asthma pathobiology merits further research. Fulfilling knowledge gaps outlined in this review could facilitate the development of new therapeutic options for patients with obesity and asthma.

Visceral adiposity index is associated with lung function impairment: a population-based study

Background

The effects of visceral adiposity on decreased lung function have drawn much attention. Recently, the visceral adiposity index (VAI) has been proposed as a visceral fat distribution and dysfunction marker. However, the relationship between the VAI and lung function has not been investigated. The objective of the study was to analyze the association between the VAI and lung function and evaluate the potential of VAI as a predictor of lung function.

Methods

We collected data from a population-based study of 1786 subjects aged 40 years or older. All subjects completed a questionnaire and underwent anthropometric measurements and laboratory tests. Linear and logistic regression models were developed to assess the association between the VAI and lung function.

Results

The VAI was inversely related to FVC%predicted in men and negatively associated with both FVC%predicted and FEV1%predicted in women. In the linear regression analysis, the decrease in FVC%predicted associated with each 10% increase in the VAI was 1.127% in men and 1.943% in women; the decrease in FEV1%predicted associated with each 10%increase in the VAI was 0.663% in men and 1.738% in women. Further regression analysis revealed that the VAI was positively correlated with FVC and FEV1 impairment in women.

Conclusions

We were the first to show a clear correlation between the VAI and lung function impairment in the Chinese population. The VAI could be a simple and reliable approach in daily practice, and individuals, especially women with a high VAI, should receive additional screening and preventive interventions for respiratory disease.

The Journal of Allergy and Clinical Immunology: In Practice 2019 Highlights

This article provides highlights of the clinically impactful original studies and reviews published in The Journal of Allergy and Clinical Immunology: In Practice in 2019 on the subjects of anaphylaxis, asthma, dermatitis, drug allergy, food allergy, immunodeficiency, immunotherapy, rhinitis/sinusitis, and urticaria/angioedema/mast cell disorders. Within each topic, practical aspects of diagnosis and management are emphasized. Treatments discussed include lifestyle modifications, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We designed this review to help readers consolidate and use this extensive and practical knowledge for the benefit of their patients.

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.

Novel Insights on Sex-Related Differences in Asthma

PURPOSE OF REVIEW

Asthma, a common respiratory disease that affects about 10% of the US population, represents a significant public health issue. In the last decade, cumulative evidence has demonstrated sex disparities in asthma, including significant differences in epidemiology, clinical presentation, response to therapies, and health outcomes. Understanding sex-related differences in asthma enables clinicians to provide personalized asthma care and improve asthma outcome.

RECENT FINDINGS

Recent studies on sex-related differences in asthma inform us on mechanism underlying asthma pathogenesis across all age groups. Sex hormones directly modulate immune pathways crucial in asthma pathogenesis and affect individual's response to environmental triggers and medications, such as leukokotriene inhibitors. Not surprisingly, the use of external sex hormone supplementations appears to modulate asthma risk. Identification of sex-specific asthma risk loci through genome-wide association studies also provides supporting evidence on sex-related differences in asthma. There is an interaction between sex and obesity, an interaction that could place females at higher risk for systemic inflammation and, consequently, asthma. In this article, we review epidemiological and clinical studies on sex-related differences in asthma, with a special focus on the role of sex hormones, including hormonal therapies and the asthma-obesity interaction.