Abdominal obesity and late-onset asthma: cross-sectional and longitudinal results: the 3C study

The association between body mass index, abdominal fatness, and weight change and the risk of adult asthma: a systematic review and meta-analysis of cohort studies

Obesity has been associated with increased risk of adult asthma, however, not all studies have found a clear association between overweight and the incidence of asthma, and data on other adiposity measures have been limited. Hence, we aimed to summarize evidence on association between adiposity and adult asthma. Relevant studies were retrieved through searches conducted in PubMed, and EMBASE up to March 2021. A total of sixteen studies (63,952 cases and 1,161,169 participants) were included in the quantitative synthesis. The summary RR was 1.32 (95% CI 1.21-1.44, I² = 94.6%, p_{heterogeneity}< 0.0001, n = 13) per 5 kg/m² increase in BMI, 1.26 (95% CI 1.09-1.46, I² = 88.6%, p_{heterogeneity} < 0.0001, n = 5) per 10 cm increase in waist circumference and 1.33 (95% CI 1.22-1.44, I² = 62.3%, p_{heterogeneity}= 0.05, n = 4) per 10 kg increase in weight gain. Although the test for nonlinearity was significant for BMI (p_nonlinearity < 0.00001), weight change (p_nonlinearity = 0.002), and waist circumference (p_nonlinearity = 0.02), there was a clear dose-response relationship between higher levels of adiposity and asthma risk. The magnitude of the associations and the consistency of the results across studies and adiposity measures provide strong evidence that overweight and obesity, waist circumference and weight gain increases asthma risk. These findings support policies to curb the global epidemic of overweight and obesity.

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 weight-adjusted-waist index with asthma prevalence and the age of first asthma onset in United States adults

OBJECTIVE

The objective of this study was to assess whether the weight-adjusted-waist index(WWI) is associated with the prevalence of asthma and age when first asthma onset appears in US adults.

METHODS

For analysis we selected participants from the National Health and Nutrition Examination Survey(NHANES)database between 2001 and 2018. A dose-response curve was calculated using logistic regression,subgroup analysis,and a dose-response curve.

RESULTS

The study included 44480 people over the age of 20,including 6061 reported with asthma, and the increase in asthma prevalence was 15% associated with each unit increase in the WWI, after adjusting for all confounders(odds ratio(OR)=1.15,95% CI:1.11,1.20). The sensitivity analysis was performed by trichotomizing the WWI, and compared to the lowest tertile, the highest tertile WWI group displayed a 29% increase in asthma prevalence(OR=1.29,95% CI:1.19,1.40). A nonlinear correlation was found between the WWI index and the risk of asthma onset, with a threshold saturation effect indicating an inflection point of 10.53 (log-likelihood ratio test, P<0.05), as well as a positive linear correlation with age at first asthma onset.

CONCLUSIONS

A higher WWI index was associated with an increased prevalence of asthma and an older age of first asthma onset.

Comorbidities in childhood-onset and adult-onset asthma

BACKGROUND

Age of asthma onset has emerged as an important determinant of asthma phenotypes; however, the comorbidities that predominate in either childhood- or adult-onset asthma are not known.

OBJECTIVE

To identify comorbidities associated with adult-onset asthma vs childhood-onset asthma and with age of asthma diagnosis.

METHODS

We analyzed data on 27,437 adult participants in the National Health and Nutrition Examination Surveys conducted from 2001 to 2018. Logistic regression adjusted for covariates was used to identify comorbidities associated with the asthma phenotypes and age of asthma diagnosis.

RESULTS

Approximately 12.6% of participants were ever diagnosed with asthma; the prevalence of childhood-onset (before 18 years old) and adult-onset (≥ 18 years old) current asthma was 2.7% and 5.5%, respectively. After adjustment for covariates including age, adult-onset asthma was associated with higher odds of obesity (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.09-1.96), hypercholesterolemia (OR, 1.67; 95% CI, 1.08-2.56), borderline high serum triglycerides (OR, 1.78; 95% CI, 1.17-2.71), and osteoarthritis (OR, 1.52; 95% CI, 1.04-2.20) than was childhood-onset asthma. Older age of asthma diagnosis (per 5-year increase) was also associated with higher odds of diabetes (OR, 1.04; 95% CI, 1.00-1.07) and hypertension (OR, 1.05; 95% CI, 1.02-1.07), whereas younger age of asthma diagnosis was associated with higher odds of chronic obstructive pulmonary disease (OR, 1.12; 95% CI, 1.04-1.19).

CONCLUSION

Age- and covariates-adjusted prevalence of obesity, dyslipidemia, arthritis, diabetes, and hypertension is higher in adult-onset asthma than in childhood-onset asthma, and with older age of asthma diagnosis. Conversely, the prevalence of chronic obstructive pulmonary disease increases with younger age of asthma diagnosis.

Asthma and metabolic syndrome: a comprehensive systematic review and meta-analysis of observational studies

Introduction: This study aimed to perform a meta-analysis on the prevalence of metabolic syndrome (MetS) among patients with asthma and to measure the association asthma has with MetS.

Methods: The Web of Science, Medline, Scopus, Embase and Google Scholar were searched using the "Asthma", "Metabolic Syndrome", "Dysmetabolic Syndrome", "Cardiovascular Syndrome", "Insulin Resistance Syndrome", "Prevalence", "Odds Ratio", "Cross-Sectional Studies", and "Case-Control Studies" keywords. All observational studies reporting the prevalence of MetS among people with and without asthma were included in the study. In the presence of heterogeneity, random-effects models were used to pool the prevalence and odds ratios (OR), as measures of association in cross-sectional and case-control/ cohort studies, respectively.

Results: The prevalence of MetS among patients with asthma (8 studies) and the OR comparing the prevalence of MetS among patients with and without asthma (5 studies) were pooled separately. The pooled prevalence of MetS among patients with asthma was found to be 25% (95% confidence interval (CI): 13%–38%). In contrast, the overall pooled OR for MetS in patients with asthma, compared to healthy controls, was 1.34 (95% CI: 0.91–1.76), which was not statistically significant.

Conclusion: The prevalence of MetS was relatively high in patients with asthma. Furthermore, the odds of MetS was higher in patients with asthma, compared to healthy controls, although this difference was not statistically significant. More original studies among different populations are needed in order to more accurately examine the association between asthma and MetS, as well as the relationship asthma has with the individual components of MetS.

Impact of Low Cardiovascular Risk Profiles on Geriatric Outcomes: Evidence From 421,000 Participants in Two Cohorts

BACKGROUND

Individuals with low cardiovascular risk factor profiles experience lower rates of cardiovascular diseases, but associations with geriatric syndromes are unclear. We tested whether individuals with low cardiovascular disease risk, aged 60-69 years old at baseline in two large cohorts, were less likely to develop aging-related adverse health outcomes.

METHODS

Data were from population representative medical records (Clinical Practice Research Datalink [CPRD] England, n = 239,591) and healthy volunteers (UK Biobank [UKB], n = 181,820), followed for ≤10 years. A cardiovascular disease risk score (CRS) summarized smoking status, LDL-cholesterol, blood pressure, body mass index, fasting glucose and physical activity, grouping individuals as low (ie, all factors near ideal), moderate, or high CRS. Logistic regression, Cox models, and Fine and Grey risk models tested the associations between the CRS and health outcomes.

RESULTS

Low CRS individuals had less chronic pain (UKB: baseline odds ratio = 0.52, confidence interval [CI] = 0.50-0.54), lower incidence of incontinence (CPRD: subhazard ratio [sub-HR] = 0.75, 0.63-0.91), falls (sub-HR = 0.82, CI = 0.73-0.91), fragility fractures (sub-HR = 0.78, CI = 0.65-0.93), and dementia (vs. high risks; UKB: sub-HR = 0.67, CI = 0.50-0.89; CPRD: sub-HR = 0.79, CI = 0.56-1.12). Only 5.4% in CPRD with low CRS became frail (Rockwood index) versus 24.2% with high CRS. All-cause mortality was markedly lower in the low CRS group (vs. high CRS; HR = 0.40, 95% CI = 0.35-0.47). All associations showed dose-response relationships, and results were similar in both cohorts.

CONCLUSIONS

Persons aged 60-69 years with near-ideal cardiovascular risk factor profiles have substantially lower incidence of geriatric conditions and frailty. Optimizing cardiovascular disease risk factors may substantially reduce the burden of morbidity in later life.

Sex differences in the association between asthma incidence and modifiable risk factors in Korean middle-aged and older adults: NHIS-HEALS 10-year cohort

Background

This study investigated the sex-specific incidence of asthma and the effects of modifiable risk factors, particularly obesity, on asthma incidence among middle-aged and older individuals in Korea.

Methods

We used data from the National Health Insurance Service-Health Screening Cohort (NHIS-HEALS), which includes health examinees aged 40–79 years in 2002–2003. In total, 459,529 participants with baseline anthropometric measurements were followed-up for 10 years and the development of asthma was evaluated (2004–2013). For subgroup analysis, 246,019 participants who had body mass index (BMI) and waist circumference (WC) measurements taken in 2008–2009 were included in the analysis of the asthma incidence for 2010–2013. Factors associated with asthma were analysed using Cox proportional hazard models.

Results

The cohort comprised 4,248,813 (men, 2,358,541; women, 1,890,272) person-years of follow-up for 2004–2013. The asthma incidence was 10.58 and 15.03 per 1000 person-years for men and women, respectively. Asthma incidence increased with age, notably so in men. Obesity based on the baseline BMI was significantly associated with asthma development in both sexes (men, HR = 1.23, 95% confidence interval (CI) = 1.13–1.34; women, HR = 1.40 95% CI = 1.32–1.48). High WC was also related to asthma incidence in both sexes with statistical significance (men, HR = 1.34, 95% CI = 1.16–1.57; women, HR = 1.19 95% CI = 1.03–1.37). Analysis of the combined effects of BMI and WC showed that men had a higher asthma risk in the group with both general obesity and abdominal obesity than in the group with non-abdominal obesity and normal BMI. However, obese women had a higher risk of asthma regardless of abdominal obesity. Similarly, smoking was associated with asthma in both sexes but drinking and physical activity showed different associations between the sexes.

Conclusions

Our results revealed that asthma incidence was substantially high at old age and lifestyle factors were associated with asthma development. Practical strategies including weight control and healthy lifestyle modification are required to prevent asthma in older people.

Association between abdominal obesity and asthma: a meta-analysis

Background

Studies evaluating the association between abdominal obesity and asthma yielded conflict results. Whether abdominal obesity is positively associated with asthma remains unclear.

Objective

To quantitatively determine the association between abdominal obesity and asthma.

Methods

Databases including PubMed, Web of Science, China National Knowledge Infrastructure, China Biology Medicine disc, Chinese Scientific and Technological Journal Database and Wanfang Data were searched up to February 2018 to collect all relevant studies. Reference lists of related articles were also checked. After study selection and data extraction, meta-analysis was conducted to calculate the pooled odds ratio (OR) and corresponding 95% confidence interval (CI). Subgroup analyses by study design and age groups of participants were further performed. Publication bias was assessed via Begg’s rank correlation and Egger’s linear regression methods.

Results

A total of 13 studies were included in the final meta-analysis, including 2 case–control studies, 6 cohort studies, and 5 cross-sectional studies. Our meta-analysis observed a positive association between abdominal obesity and asthma (OR = 1.47, 95% CI 1.35–1.59). No evidence of heterogeneity (I² = 10.7%) or publication bias (Begg’s test P = 0.200, Egger’s test P = 0.146) was found. Subgroup analyses by study design and age groups of participants obtained consistently positive results across subgroups. Moreover, our meta-analysis observed similar results when considering this association separately in males and females (Males: OR = 1.37, 95% CI 1.18–1.58; Females: OR = 1.39, 95% CI 1.22–1.58). In addition, the association between abdominal overweight and asthma was further explored in this meta-analysis and the pooled OR and 95% CI was 1.13 (1.03, 1.24), indicating that there is a dose–response relationship between abdominal weight status and asthma.

Conclusions

Our meta-analysis shows a positive association between abdominal obesity and asthma. Moreover, this association is similar in males and females. In addition, our meta-analysis indicates that there is a dose–response relationship between abdominal weight status and asthma. Therefore, addressing abdominal obesity issue is of great importance. More studies are needed in the future to clarify the association between abdominal obesity and asthma.

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.

Leukotriene Receptor Antagonists for the Treatment of Asthma in Elderly Patients

Elderly asthma (EA) is regarded as a distinct phenotype of asthma and is associated with age-related changes in airway structure and alterations in lung function and immune responses. EA is difficult to diagnose because of aging and co-morbidities, and overlaps with fixed airway obstructive disease. Novel modalities to differentiate between EA and chronic obstructive pulmonary disease (COPD) are necessary. A multifaceted approach, including clinical history, smoking habits, atopy, and measurement of lung function, is mandatory to differentiate asthma from COPD. There are a variety of co-morbidities with EA, of which COPD, upper airway diseases, depression, obesity, and hypertension are the most common, and these co-morbidities can affect the control status of EA. However, leukotriene receptor antagonists (LTRAs) can facilitate the management of EA, and thus addition of an LTRA to inhaled corticosteroid (ICS) monotherapy or ICS plus long-acting β₂-agonist therapy improves symptoms in EA patients. LTRA treatment is safe and beneficial in patients who are unable to use inhalation devices properly or who have co-morbid diseases. Therefore, clinical studies targeting a specific population of EA patients are warranted to help achieve a better therapeutic strategy in EA patients.

The functional and clinical outcomes of exercise training following a very low energy diet for severely obese women: study protocol for a randomised controlled trial

Background

Clinical practice guidelines globally recommend lifestyle modification including diet and exercise training as first-line treatment for obesity. The clinical benefits of exercise training in adults with obesity is well-documented; however, there is no strong evidence for the effectiveness of exercise training for weight loss in class II and class III obesity. The purpose of the randomised controlled trial described in this protocol article is to examine the effect of exercise training, in addition to a very low energy diet (VLED), in clinically severe obese women for changes in body composition, physical function, quality of life, and markers of cardiometabolic risk.

Methods/Design

Sixty women, aged 18–50 years with a body mass index (BMI) greater than 34.9 kg.m² and at least one obesity-related co-morbidity, will be recruited for this 12-month study. Participants will be randomised to either exercise plus energy restriction (n = 30), or energy restriction alone (n = 30). All participants will follow an energy-restricted individualised diet incorporating a VLED component. The exercise intervention group will also receive exercise by supervised aerobic and resistance training and a home-based exercise programme totalling 300 minutes per week. Primary outcome measures include body composition and aerobic fitness. Secondary outcome measures include: physical function, cardiometabolic risk factors, quality of life, physical activity, and mental health. All outcome measures will be conducted at baseline, 3, 6 and 12 months.

Discussion

Previous research demonstrates various health benefits of including exercise training as part of a healthy lifestyle at all BMI ranges. Although clinical practice guidelines recommend exercise training as part of first-line treatment for overweight and obesity, there are few studies that demonstrate the effectiveness of exercise in class II and class III obesity. The study aims to determine whether the addition of exercise training to a VLED provides more favourable improvements in body composition, physical function, quality of life, and markers of cardiometabolic risk for women with clinically severe obesity, compared to VLED alone.

Trial registration

Australian New Zealand Clinical Trials Registry (ACTRN12611000694910). Date registered: 4 July 2011

Prevalence and risk factors for allergic rhinitis in two resource-limited settings in Peru with disparate degrees of urbanization

BACKGROUND

Allergic rhinitis is a disease with a high global disease burden, but risk factors that contribute to this condition are not well understood.

OBJECTIVE

To assess the prevalence and risk factors of allergic rhinitis in two Peruvian populations with disparate degrees of urbanization.

METHODS

We conducted a population-based, cross-sectional study on 1441 children aged 13-15 years at enrollment (mean age 14.9 years, 51% boys) to investigate the prevalence of allergic disease. We used a standardized, Spanish validated questionnaire to determine the prevalence of allergic rhinitis and asked about sociodemographics and family history of allergies. Children also underwent spirometry, exhaled nitric oxide, allergy skin testing to 10 common household allergens and provided a blood sample for measurement of 25OH vitamin D and total serum IgE.

RESULTS

Overall prevalence of allergic rhinitis was 18% (95% CI 16% to 20%). When stratified by site, the prevalence of allergic rhinitis was 23% Lima vs. 13% in Tumbes (P < 0.001); however, this difference was no longer significant after controlling for subject-specific factors (P = 0.95). There was a strong association with other allergic diseases: 53% of children with asthma had allergic rhinitis vs. 15% in those without asthma (P < 0.001) and 42% of children with eczema vs. 17% of those without eczema (P < 0.001). Important risk factors for allergic rhinitis were parental rhinitis (adjusted OR = 3.0, 95% CI 1.9-4.7 for 1 parent and adjusted OR = 4.4, 95% CI 1.5-13.7 for 2 parents); allergic sensitization to common household aeroallergens (1.6, 1.1-2.3); being overweight (1.5, 1.0-2.3); exhaled nitric oxide ≥ 20 ppb (1.9, 1.3-2.7); and total serum IgE ≥ 95th percentile (2.4, 1.2-4.8). Population attributable risk of important factors for allergic rhinitis were 25% for high exhaled nitric oxide, 22% for allergic sensitization to common household aeroallergens, 22% for paternal rhinitis, 10% for being overweight and 7% for an elevated total serum IgE.

CONCLUSION AND CLINICAL RELEVANCE

Allergic rhinitis was prevalent in both settings, and important risk factors include elevated exhaled nitric oxide, allergic sensitization to common household aeroallergens, parental rhinitis, being overweight and high total serum IgE. When considering subject-specific factors, the difference in prevalence between the urban and rural settings became non-important.

Metabolic Syndrome Is Associated with Increased Oxo-Nitrative Stress and Asthma-Like Changes in Lungs

Epidemiological studies have shown an increased obesity-related risk of asthma. In support, obese mice develop airway hyperresponsiveness (AHR). However, it remains unclear whether the increased risk is a consequence of obesity, adipogenic diet, or the metabolic syndrome (MetS). Altered L-arginine and nitric oxide (NO) metabolism is a common feature between asthma and metabolic syndrome that appears independent of body mass. Increased asthma risk resulting from such metabolic changes would have important consequences in global health. Since high-sugar diets can induce MetS, without necessarily causing obesity, studies of their effect on arginine/NO metabolism and airway function could clarify this aspect. We investigated whether normal-weight mice with MetS, due to high-fructose diet, had dysfunctional arginine/NO metabolism and features of asthma. Mice were fed chow-diet, high-fat-diet, or high-fructose-diet for 18 weeks. Only the high-fat-diet group developed obesity or adiposity. Hyperinsulinemia, hyperglycaemia, and hyperlipidaemia were common to both high-fat-diet and high-fructose-diet groups and the high-fructose-diet group additionally developed hypertension. At 18 weeks, airway hyperresponsiveness (AHR) could be seen in obese high-fat-diet mice as well as non-obese high-fructose-diet mice, when compared to standard chow-diet mice. No inflammatory cell infiltrate or goblet cell metaplasia was seen in either high-fat-diet or high-fructose-diet mice. Exhaled NO was reduced in both these groups. This reduction in exhaled NO correlated with reduced arginine bioavailability in lungs. In summary, mice with normal weight but metabolic obesity show reduced arginine bioavailability, reduced NO production, and asthma-like features. Reduced NO related bronchodilation and increased oxo-nitrosative stress may contribute to the pathogenesis.

Challenges in the Management of Asthma in the Elderly

Recent literature has emphasized the clinical and socio-epidemiological significance of asthma in the elderly. However, why the disease burden remains high in this group is unclear. Elderly subjects usually have multiple chronic illnesses, and the role played by comorbidities in the context of asthma has been underappreciated. This review aims to summarize the literature associations between comorbidities and asthma in elderly patients. In addition, we discuss patient management issues.

Potential role of the airway wall in the asthma of obesity

The pathogenesis of late-onset TH2-low asthma in obesity is thought to be related to weight-related decreases in lung volume, but why only a subset of individuals with obesity develop this condition is unknown. We tested the hypothesis that natural variations in both airway wall stiffness and airway wall thickness could lead to a subpopulation of hyperresponsive individuals exhibiting the symptoms of asthma in the setting of obesity. Increases in airway resistance (Raw) after airway smooth muscle stimulation were simulated using a computational model of an elastic airway embedded in elastic parenchyma. Using a range of randomly chosen values for both airway wall stiffness and thickness, we determined the resulting probability distributions of Raw responsiveness for a variety of different levels of transpulmonary pressure (Ptp). As Ptp decreased from 5 to 1 cmH2O, the resulting distributions of Raw moved toward progressively higher levels of responsiveness. With appropriate choices for the mean and standard deviation of the parameter that controls either airway wall stiffness or thickness, the model predicts a relationship between airway hyperresponsiveness and body mass index that is similar to that which has been reported in populations with obesity. We conclude that natural variations in airway wall mechanics and geometry between different individuals can potentially explain why an increasing percentage of the population exhibits the symptoms of asthma as the obesity of the population increases.

Associations between central obesity and asthma in children and adolescents: a case-control study

INTRODUCTION

Evidence supports a significant yet weak association between high-body weight and asthma in children. However, most studies investigating the obesity-asthma link use Body Mass Index (BMI) to evaluate body fatness. The relationship between body fat distribution and asthma remains largely unknown, especially in children. This pediatric case-control investigation examined associations between central obesity/high-body weight and asthma diagnosis.

METHODS

Five-hundred and fourteen children (217 physician diagnosed asthma cases and 297 healthy controls) of 5-11 years were recruited. Height, weight and waist circumference were measured. Asthma symptoms, past medical history, personal lifestyle, socioeconomic status, diet and physical activity history were also collected.

RESULTS

A higher proportion of children with asthma were centrally obese [(≥90th waist percentile) 15.2 vs. 9.4%, p<0.0001; (≥90th waist-to-height ratio percentile) 39.6 vs. 24.2%, p<0.0001)]. Regression analyses revealed that centrally obese children were more likely to have asthma (high-waist circumference (OR = 1.99, 95% CI: 1.07-3.68) and high-waist circumference to height ratio (OR = 2.24, 95% CI: 1.47-3.40), following adjustment for various confounders. Overweight/obese participants (BMI defined) were more likely to be asthmatic [odds ratio (OR) = 1.52, 95% confidence interval (CI): 1.03-2.70)] when compared to controls.

CONCLUSIONS

Presence of central obesity and high-body weight (at least overweight) as assessed by waist circumference, waist-to-height ratio, and BMI are associated with asthma diagnosis. More studies are needed, especially in children and adolescents, to confirm these findings and better understand how body fat distribution impacts the obesity-asthma relationship.

Effect of antigen sensitization and challenge on oscillatory mechanics of the lung and pulmonary inflammation in obese carboxypeptidase E-deficient mice

Atopic, obese asthmatics exhibit airway obstruction with variable degrees of eosinophilic airway inflammation. We previously reported that mice obese as a result of a genetic deficiency in either leptin (ob/ob mice) or the long isoform of the leptin receptor (db/db mice) exhibit enhanced airway obstruction in the presence of decreased numbers of bronchoalveolar lavage fluid (BALF) eosinophils compared with lean, wild-type mice following antigen (ovalbumin; OVA) sensitization and challenge. To determine whether the genetic modality of obesity induction influences the development of OVA-induced airway obstruction and OVA-induced pulmonary inflammation, we examined indices of these sequelae in mice obese as a result of a genetic deficiency in carboxypeptidase E, an enzyme that processes prohormones and proneuropeptides involved in satiety and energy expenditure (Cpe(fat) mice). Accordingly, Cpe(fat) and lean, wild-type (C57BL/6) mice were sensitized to OVA and then challenged with either aerosolized PBS or OVA. Compared with genotype-matched, OVA-sensitized and PBS-challenged mice, OVA sensitization and challenge elicited airway obstruction and increased BALF eosinophils, macrophages, neutrophils, IL-4, IL-13, IL-18, and chemerin. However, OVA challenge enhanced airway obstruction and pulmonary inflammation in Cpe(fat) compared with wild-type mice. These results demonstrate that OVA sensitization and challenge enhance airway obstruction in obese mice regardless of the genetic basis of obesity, whereas the degree of OVA-induced pulmonary inflammation is dependent on the genetic modality of obesity induction. These results have important implications for animal models of asthma, as modeling the pulmonary phenotypes for subpopulations of atopic, obese asthmatics critically depends on selecting the appropriate mouse model.

Asthma in the elderly: what we know and what we have yet to know

In the past, asthma was considered mainly as a childhood disease. However, asthma is an important cause of morbidity and mortality in the elderly nowadays. In addition, the burden of asthma is more significant in the elderly than in their younger counterparts, particularly with regard to mortality, hospitalization, medical costs or health-related quality of life. Nevertheless, asthma in the elderly is still been underdiagnosed and undertreated. Therefore, it is an imperative task to recognize our current challenges and to set future directions. This project aims to review the current literature and identify unmet needs in the fields of research and practice for asthma in the elderly. This will enable us to find new research directions, propose new therapeutic strategies, and ultimately improve outcomes for elderly people with asthma. There are data to suggest that asthma in older adults is phenotypically different from young patients, with potential impact on the diagnosis, assessment and management in this population. The diagnosis of AIE in older populations relies on the same clinical findings and diagnostic tests used in younger populations, but the interpretation of the clinical data is more difficult. The challenge today is to encourage new research in AIE but to use the existing knowledge we have to make the diagnosis of AIE, educate the patient, develop a therapeutic approach to control the disease, and ultimately provide a better quality of life to our elderly patients.

The effects of exercise training in addition to energy restriction on functional capacities and body composition in obese adults during weight loss: a systematic review

BACKGROUND

Obesity is associated with impairments of physical function, cardiovascular fitness, muscle strength and the capacity to perform activities of daily living. This review examines the specific effects of exercise training in relation to body composition and physical function demonstrated by changes in cardiovascular fitness, and muscle strength when obese adults undergo energy restriction.

METHODS

Electronic databases were searched for randomised controlled trials comparing energy restriction plus exercise training to energy restriction alone. Studies published to May 2013 were included if they used multi-component methods for analysing body composition and assessed measures of fitness in obese adults.

RESULTS

Fourteen RCTs met the inclusion criteria. Heterogeneity of study characteristics prevented meta-analysis. Energy restriction plus exercise training was more effective than energy restriction alone for improving cardiovascular fitness, muscle strength, and increasing fat mass loss and preserving lean body mass, depending on the type of exercise training.

CONCLUSION

Adding exercise training to energy restriction for obese middle-aged and older individuals results in favourable changes to fitness and body composition. Whilst weight loss should be encouraged for obese individuals, exercise training should be included in lifestyle interventions as it offers additional benefits.

Body mass index is a stronger predictor than the metabolic syndrome for future asthma in women. The longitudinal CARDIA study

RATIONALE

It is hypothesized that the metabolic syndrome explains the association between body mass index (BMI) and asthma in adults.

OBJECTIVES

Our objective was to longitudinally compare the relative strengths of the associations of the metabolic syndrome and BMI with incident asthma in adults.

METHODS

We included 4,619 eligible participants in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort followed over 25 years. Incident asthma was defined by a new self-reported provider asthma diagnosis plus either the presence of asthma symptoms and/or use of asthma medications. Cox proportional hazard analyses were performed.

MEASUREMENTS AND MAIN RESULTS

Six hundred two subjects (417 women and 185 men) developed incident asthma over 25 years of follow-up. Metabolic syndrome predicted incident asthma among women but not men (unadjusted hazard ratios, 1.50 and 0.98; P = 0.01 and 0.93, respectively). BMI had a similar predictive association among women but not men (unadjusted hazard ratios, 1.19 and 1.04 per 5 units of BMI; P < 0.001 and 0.60, respectively). The association of metabolic syndrome with incident asthma in women was no longer statistically significant after adjustment for BMI (P = 0.44). In contrast, the association of BMI with incident asthma in women remained statistically significant after adjusting for the metabolic syndrome (P = 0.01). In a stepwise model, BMI was a stronger predictor than the metabolic syndrome (P = 0.001).

CONCLUSIONS

BMI is a stronger predictor of incident asthma among women than the metabolic syndrome. Other obesity-associated factors that are not a part of the metabolic syndrome may play a role in the BMI-asthma association in women.

Exploring the obesity-asthma link: do all types of adiposity increase the risk of asthma?

BACKGROUND

Obesity and risk of asthma are linked. Different distributions of adiposity, such as visceral, subcutaneous or ectopic adiposity, may affect asthma risk differently.

OBJECTIVE

To explore the association of different adiposity types with self-reported asthma, bronchial inflammation and lung function, accounting for possible effect modifiers, such as atopy and gender.

METHODS

In a general population sample of 3471 persons aged 19-72, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured by ultrasound, and fat percentage by bio-impedance. Body mass index, waist circumference, waist-to-hip ratio (WHR), bronchial inflammation as fractional expiratory nitric oxide (FeNO), lung function [FEV(1) and forced vital capacity (FVC)], and atopy (specific IgE) were measured.

RESULTS

All adiposity measures were associated with a higher risk of asthma. The risk estimates (odds ratios, OR, with 95% confidence interval, CI) of current asthma were of similar magnitude for all six adiposity measures ranging between 1.17, CI = 0.98-1.40 (SAT) and 1.51, CI = 1.17-1.95 (WHR). The adiposity-asthma associations were significantly stronger in non-atopics than in atopics. In non-atopics the risk estimates of current asthma ranged between 1.35 CI = 1.08-1.72 and 1.82 CI = 1.34-2.46 for SAT and WHR respectively. Consistent results were obtained using dichothomized adiposity measures (obese vs. non-obsese). The FVC and FEV(1) decreased significantly with increasing adiposity in both atopics and non-atopics, e.g. FVC decreased between 36 mL (CI = 10, 62 mL) and 155 mL (CI = 124, 186 mL) for one unit (standard error) increase of SAT and VAT respectively. Adiposity measures were not associated with atopy and not consistently associated with FeNO levels.

CONCLUSIONS AND CLINICAL RELEVANCE

The effect of adiposity on asthma was mainly seen in non-atopics and did not appear to depend on the distribution of adiposity as reflected by the adiposity measures used in the present study. Increasing adiposity was associated with lower lung function independent of atopic status.

Association between obesity and asthma in the elderly population: potential roles of abdominal subcutaneous adiposity and sarcopenia

BACKGROUND

Obesity is a significant risk factor for asthma; however, the association of asthma with obesity has rarely been studied in the elderly population. The role of central obesity has been suggested as a link between the 2 entities but has not been comprehensively studied in elderly populations.

OBJECTIVE

To investigate the mechanisms of association between obesity and asthma in the elderly population.

METHODS

This cross-sectional analysis included 994 participants (aged ≥65 years) in the Korean Longitudinal Study on Health and Aging. Asthma was defined by using questionnaires. Spirometry and chest radiography were performed to exclude asthma-mimicking conditions. Measurements of abdominal subcutaneous and visceral fat were calculated by computed tomography of the abdomen, and regional body compositions were measured by dual energy X-ray absorptiometry. Biochemical parameters were also measured.

RESULTS

The prevalence of asthma was 5.4%. The study population had a mean body mass index (BMI) of 24.0. Multivariate logistic regression tests revealed that the risk of asthma increased in proportion to an increase in BMI or abdominal subcutaneous adiposity. However, no association was found with visceral adiposity, serum adiponectin levels, or serum vitamin D levels. The dual energy X-ray absorptiometry-measured appendicular fat-free mass index was inversely related to asthma among patients with a BMI of 25.0 or greater.

CONCLUSION

Our findings suggest that the relationships between obesity and asthma in the elderly population may be mediated by factors such as abdominal subcutaneous adiposity and sarcopenia. These associations warrant further investigations to identify their potential roles.