Body fat mass distribution and interrupter resistance, fractional exhaled nitric oxide, and asthma at school-age

Body composition and respiratory outcomes in children: a population-based prospective cohort study

BACKGROUND

Body composition might influence lung function and asthma in children, but its longitudinal relations are unclear. We aimed to identify critical periods for body composition changes during childhood and adolescence in relation to respiratory outcomes in adolescents.

METHODS

In a population-based prospective cohort study, we measured body mass index, fat mass index (FMI), lean mass index (LMI) and the ratio of android fat mass divided by gynoid fat mass (A/G ratio) by dual-energy X-ray absorptiometry at 6, 10 and 13 years. At 13 years, lung function was measured by spirometry, and current asthma was assessed by questionnaire.

RESULTS

Most prominently and consistently, higher FMI and A/G ratio at age 13 years were associated with lower forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) and forced expiratory flow after exhaling 75% of FVC (FEF75) (range Z-score difference -0.13 (95% CI -0.16 to -0.10) to -0.08 (95% CI -0.11 to -0.05) per SD score increase), and higher LMI at all ages was associated with higher FEF75 (range Z-score difference 0.05 (95% CI 0.01 to 0.08) to 0.09 (95% CI 0.06 to 0.13)). Between the ages of 6 and 13 years, normal to high FMI and A/G ratio were associated with lower FEV1/FVC and FEF75 (range Z-score difference -0.20 (95% CI -0.30 to -0.10) to -0.17 (95% CI -0.28 to -0.06)) and high to high LMI with higher FEF75 (range Z-score difference0.32 (95% CI 0.23 to 0.41)). Body composition changes were not associated with asthma.

CONCLUSION

Adolescents with higher total and abdominal fat indices may have impaired lung function, while those with a higher lean mass during childhood and adolescence may have better small airway function. Public health measures should focus on a healthy body composition in adolescents to minimise respiratory morbidity.

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.

The role of monocytes and natural killers' immunophenotypic subsets in bronchial asthma in children

Objective: Childhood bronchial asthma (BA) is a globally significant chronic disease with major health consequences. Recently, focus on the role of the innate immune system has been highlighted. Therefore, this study explores the role of circulating monocytes and natural killer (NK) clusters in childhood asthma.Methods: This case-control study enrolled 50 children with asthma divided equally into severe and mild groups and 26 healthy children. Flow-cytometry analysis was used to identify circulating blood monocytes and natural killers' subsets. In addition, pulmonary function test (spirometry) for children with asthma was performed.Results: This study showed significant negative correlations between frequency of total circulating, classical, intermediate, and nonclassical monocytes with ratio of forced expiratory volume/forced vital capacity (FEV1/FVC) (r = -0.637, P < 0.001; r = -0.575, P < 0.001; r = -0.657, P < 0.001; r = -0.329, P = 0.004, respectively). Also, there was significant negative correlations between frequency of total NKs and CD56^dim CD16+ NK with FEV1/FVC (r = -0.584, P < 0.001) and (r = -0.579, P < 0.001). Significant predictors of childhood asthma severity were frequencies of total monocytes, total NKs, intermediate monocytes, and CD56^dimCD16+ NK.Conclusion: Finally, we concluded that the FEV1/FVC is linked to aberrations of monocytes' and natural killers' immunophenotypic subsets in children with asthma. The frequencies of total monocytes and NK are significant predictors of severity of childhood asthma. The frequencies of CD14^high CD16+ intermediate monocytes and CD56^dim CD16+ NK cells are the best independent predictors of severity in children with asthma.

Does BMI Modify the Association between Vitamin D and Pulmonary Function in Children of the Mild Asthma Phenotype?

Vitamin D deficiency and obesity are global health problems that are associated with increased asthma risk in children. The purpose of this study was to investigate whether BMI modifies pulmonary function across vitamin D tertiles in pediatric asthma patients of the mild asthma phenotype. This cross-sectional study conducted from November 2016-September 2017 compared lung function variability as assessed by spirometry and nitric oxide in exhaled breath (FeNO) among 35 normal-weight and 26 overweight/obese Greek schoolchildren (5-12 years old) with mild asthma. Serum 25 (OH)D levels ≥ 30 ng/mL were defined as 'sufficient', 20-30 ng/mL 'insufficient', and <20 ng/mL 'deficient'. Stratification by BMI category, linear regression showed positive associations between D, % FVC (β = 0.49, 95%CI: 0.05, 0.94), and % FEV₁ (β = 0.48, 95%CI: -0.01, 0.95) in the normal-weight only, adjusted for age, sex, regular exercise, and medication. FEV₁ was 10% higher in the normal-weight D-sufficient group compared to those D-deficient (β = 10.43, 95%CI: 0.54, 20.32). No associations were observed for the overweight/obese group or FeNO. In conclusion, BMI modified associations of vitamin D on airway mechanics in children of the mild asthma phenotype. Serum 25 (OH)D concentrations ≥ 30 ng/mL were associated with higher ventilation in central airways of normal-weight asthmatic children.

Trajectories of adiposity indicators and association with asthma and lung function in urban minority children

BACKGROUND

A relationship between adiposity and asthma has been described in some cohort studies, but little is known about trajectories of adiposity throughout early childhood among children at high risk for developing asthma in urban United States cities. Moreover, early life trajectories of adipokines that have metabolic and immunologic properties have not been comprehensively investigated.

OBJECTIVE

Our objective was to characterize trajectories of adiposity in a longitudinal birth cohort of predominately Black and Latinx children (n = 418) using several different repeated measures including body mass index (BMI) z score, bioimpedance analysis, leptin, and adiponectin in the first 10 years of life.

METHODS

In a longitudinal birth cohort of predominately Black and Latinx children, we used repeated annual measures of BMI, bioimpedance analysis (ie, percentage of body fat), leptin, and adiponectin to create trajectories across the first 10 years of life. Across those trajectories, we compared asthma diagnosis and multiple lung function outcomes, including spirometry, impulse oscillometry, and methacholine response.

RESULTS

Three trajectories were observed for BMI z score, bioimpedance analysis, and leptin and 2 for adiponectin. There was no association between trajectories of BMI, percentage of body fat, leptin, or adipokine and asthma diagnosis or lung function (P > .05).

CONCLUSIONS

Trajectories of adiposity were not associated with asthma or lung function in children at high risk for developing asthma. Risk factors related to geography as well as social and demographic factors unique to specific populations could explain the lack of association and should be considered in obesity and asthma studies.

The impact of obesity on immune function in pediatric asthma

PURPOSE OF REVIEW

Pediatric obese asthma is a complex disease that remains poorly understood. The increasing worldwide incidence of both asthma and obesity over the last few decades, their current high prevalence and the challenges in treating obese asthmatic patients all highlight the importance of a better understanding of the pathophysiological mechanisms in obese asthma. While it is well established that patients with obesity are at an increased risk of developing asthma, the mechanisms by which obesity drives the onset of asthma, and modifies existing asthma, remain unclear. Here, we will focus on mechanisms by which obesity alters immune function in asthma.

RECENT FINDINGS

Lung parenchyma has an altered structure in some pediatric obese asthmatics, known as dysanapsis. Central adiposity is linked to reduced pulmonary function and a better predictor of asthma risk in children than BMI. Obesity in young children is associated with an increased risk of developing asthma, as well as early puberty, and hormonal alterations are implicated in obese asthma. Obesity and asthma each yield immunometabolic dysregulation separately and we are learning more about alterations in these pathways in pediatric obese asthma and the potential impact of bariatric surgery on those processes.

SUMMARY

The recent progress in clarifying the connections between childhood obesity and asthma and their combined impacts on immune function moves us closer to the goals of improved understanding of the pathophysiological mechanisms underpinning obese asthma and improved therapeutic target selection. However, this common inflammatory disease remains understudied, especially in children, and much remains to be learned.

Resting Energy Expenditure Is Elevated in Asthma

Background: Asthma physiology affects respiratory function and inflammation, factors that may contribute to elevated resting energy expenditure (REE) and altered body composition. Objective: We hypothesized that asthma would present with elevated REE compared to weight-matched healthy controls. Methods: Adults with asthma (n = 41) and healthy controls (n = 20) underwent indirect calorimetry to measure REE, dual-energy X-ray absorptiometry (DEXA) to measure body composition, and 3-day diet records. Clinical assessments included spirometry, fractional exhaled nitric oxide (FENO), and a complete blood count. Results: Asthmatics had greater REE than controls amounting to an increase of ~100 kcals/day, even though body mass index (BMI) and body composition were similar between groups. Inclusion of asthma status and FENO in validated REE prediction equations led to improved estimates. Further, asthmatics had higher white blood cell (control vs. asthma (mean ± SD): 4.7 ± 1.1 vs. 5.9 ± 1.6, p < 0.01) and neutrophil (2.8 ± 0.9 vs. 3.6 ± 1.4, p = 0.02) counts that correlated with REE (both p < 0.01). Interestingly, despite higher REE, asthmatics reported consuming fewer calories (25.1 ± 7.5 vs. 20.3 ± 6.0 kcals/kg/day, p < 0.01) and carbohydrates than controls. Conclusion: REE is elevated in adults with mild asthma, suggesting there is an association between REE and the pathophysiology of asthma.

Obesity in young children and its relationship with diagnosis of asthma, vitamin D deficiency, iron deficiency, specific allergies and flat-footedness: A systematic review and meta-analysis

There is evidence that a number of medical conditions and co-morbidities are associated with obesity in young children. This review explored whether there is evidence of associations with other conditions or co-morbidities. Observational studies of young children (mean age < 10 years) were identified using electronic searches of five databases (MEDLINE, Embase, CINAHL, AMED and SPORTDiscus). Of 27 028 studies screened, 41 (comprising 44 comparisons) met the inclusion criteria. These studies provided data on five distinct diseases/conditions: asthma (n = 16), vitamin D deficiency (n = 10), iron deficiency (n = 10), allergies (n = 4) and flat-footedness (n = 4). Thirty-two studies were appropriate for meta-analysis using random-effects models, and revealed obesity was significantly associated with having asthma (OR 1.5, 95% CI 1.3-1.7), vitamin D deficiency (OR 1.9, 95% CI 1.4-2.5) and iron deficiency (OR 2.1, 95% CI 1.4-3.2). Heterogeneity (I2 ) ranged from 57% to 61%. Narrative synthesis was conducted for all studies. There was no evidence of a consistent association between obesity in young children and eczema, dermatitis or rhinitis due to the low number of studies. However, there was an association with flat-footedness. These results have implications for health policy and practice and families. Further research leading to a greater understanding of the associations identified in this review is suggested.

Overweight Proxies Are Associated with Atopic Asthma: A Matched Case-Control Study

BACKGROUND

Many studies have documented a link between overweight and asthma in children with contradictory results regarding the best way to measure overweight. Moreover, often, the dynamic development of atopy, overweight, and asthma is controlled for age dependency insufficiently.

OBJECTIVE

This study assesses and compares the associations of overweight measured as waist circumference, waist to height ratio (WHtR), neck circumference, and body mass index with the occurrence of asthma - best possibly controlling for age-dependencies of these parameters.

METHODS

From a sample of 2,511 children aged 6-17 years, we matched 157 children with asthma with 2 controls (n = 471) according to age and atopy status and performed conditional logistic regression analyses. We further investigated the role of known influencing factors of asthma occurrence.

RESULTS

In children with atopy, all overweight proxies were consistently positively associated with asthma. Statistical significance was reached for WHtR-SD score (OR 1.26, 95% CI 1.03-1.54, p = 0.025) and persisted when further covariates, such as birth weight or social status, were added to the model. Groups of atopic versus nonatopic participants do not differ in levels of interleukin-6 or high-sensitivity C-reactive protein.

CONCLUSION

In our cohort, overweight seems to carry a risk for asthma only if accompanied with atopy. We call for more strict age matching in pediatric cohort studies and longitudinal studies for a better understanding for causal links of overweight, atopy, and asthma.

Obesity Does Not Increase the Risk of Asthma Readmissions

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

Asthma and body mass definitions affect estimates of association: evidence from a community-based cross-sectional survey

Asthma and obesity have been on the rise for the past few decades, becoming the most prevalent chronic conditions in children [1, 2]. Obesity has been suggested to increase asthma incidence and prevalence, and change asthma towards a more difficult-to-control phenotype [3]. Yet, the impact of heterogeneous asthma and obesity definitions on the suggested association has been poorly explored. As such, we aimed to evaluate the influence of different asthma and obesity definitions on the obesity–asthma relationship.

Differing body mass classifications challenge the strength of the epidemiological evidence suggesting asthma and obesity are linked. The relationship between asthma and overweight in children depends on the body mass definitions adopted.http://bit.ly/2lSxhC5

[The impact of obesity on respiratory function]

The respiratory impact of obesity can be both symptomatic (resting and exertional breathlessness) and functional (pulmonary function at rest and on exercise). The prevalence of breathlessness is increased in adult obese individuals, ∼50% at rest and ∼75% on exertion (mMRC score>0). Pulmonary function abnormalities in obese adults include reduced functional residual capacity (FRC) and expiratory residual volume (ERV), and less frequently reduced total lung capacity (a restrictive defect, with TLC below the 5th percentile of predicted is present in around 15% in severe obese adults), with normal residual volume (RV). Airflows are barely affected by obesity, but bronchial hyperresponsiveness (BHR) is very prevalent, which may be due to the loss of bronchoprotective effect of deep inspiration in obesity (mechanical pathophysiology of BHR). In children, the modifications of lung volumes seen are quite different: TLC is normal while FRC and RV are reduced, explaining the increase in FVC. FEV1/FVC is therefore reduced by obesity, without true airflow obstruction (dysanaptic growth). Resting oxygen consumption (V'O₂) is increased due to obesity and normally increases with exercise. Maximum V'O₂ is normal or weakly reduced in obese patients; on the other hand, the increase in respiratory load increases the oxygen cost of ventilation, which tends to be rapid, both at rest and during exertion. Finally, it should be noted that there is only limited statistical correlation between exercise dyspnoea and respiratory function abnormalities in obesity.

Phenotypes favoring fractional exhaled nitric oxide discordance vs guideline-based uncontrolled asthma

BACKGROUND

Despite potential value of identification of allergic inflammation with fractional exhaled nitric oxide (FeNO) in managing asthma, randomized clinical trials have not consistently shown better outcomes compared with guideline management alone.

OBJECTIVE

To assess the effectiveness of FeNO vs non-FeNO-based therapeutic algorithms in managing asthma, and the phenotypic profile associated with FeNO >35 ppb yet well controlled by guidelines, as a potential model to predict better FeNO-based algorithm outcomes.

METHODS

This is a randomized controlled study (RCT) in 88 high-risk children with asthma 7 to 18 years of age across 352 visits over a 1-year period. Generalized estimating equations analysis assessed algorithm group differences in outcomes and characteristics associated with higher odds uncontrolled by FeNO alone in the treatment decision algorithm.

RESULTS

The FeNO treatment algorithm did not show superiority in reducing exacerbations and morbidity (P > .05). Phenotypes that more than doubled the odds FeNO alone identified uncontrolled asthma included adolescence, non-adherence, high atopy (>6+), and baseline FeNO >35 ppb, whereas obesity, FEF_25-75% < 65% predicted, and bronchodilator response >10% decreased the odds. Uncontrolled asthma by FeNO alone (F) vs guidelines alone (G) showed overall F/G > 1.0 in adolescents, but <1.0 in younger patients unless the FeNO threshold was reduced to >20 ppb.

CONCLUSION

Our study suggests that age and phenotypes play a key role in FeNO discordance compared with the conventional guideline-based uncontrolled asthma. The FeNO-based therapeutic algorithm, if confirmed further, could provide the clinician with an effective asthma management tool. The clinical implication could improve future FeNO-based RCTs and treatment decision algorithms in managing asthma by considering phenotypes and age-dependent FeNO thresholds.

Asthma, exercise and metabolic dysregulation in paediatrics

Asthma is the most frequent chronic disease in childhood. Chest tightness, cough, wheezing and dyspnoea during or after exercise may be unique manifestations of asthma in up to 90% of subjects. Physical activity may be reduced by uncontrolled asthma symptoms and parental beliefs, impairing physical fitness of asthmatic children. Clinicians working in the field of allergy are aware of evidence supporting the benefits of physical activity for patients with asthma. Treatment of asthma is required in order to obtain its control and to avoid any limitation in sports and active play participation. As exercise performance in children with controlled asthma is not different from that of healthy controls, any exercise limitation cannot be accepted. Overweight and obesity may interfere with asthma and exercise, leading to dyspnoea symptoms. Evidences on the effect of insulin resistance on airway smooth muscle and on bronchial hyperactivity are presented. CONCLUSION: Exercise is part of the strategy to obtain the best control of asthma in childhood, but we have to optimise the asthma control therapy before starting exercise programming. Furthermore, it is crucial to give best attention on the effects of obesity and insulin resistance, because they could in turn influence patients' symptoms.

Fetal and Infant Growth Patterns and Risk of Lower Lung Function and Asthma. The Generation R Study

RATIONALE

Children with lower birth weight are at increased risk of asthma symptoms.

OBJECTIVES

To examine associations of fetal and infant growth with childhood lung function and asthma.

METHODS

This study was embedded in a population-based prospective cohort study of 5,635 children. Growth was estimated by repeated ultrasounds in the second and third trimesters, and measured at birth and at 3, 6, and 12 months. At age 10 years, spirometry was performed and asthma was assessed by parental questionnaire. Restricted and accelerated growth were defined as the growth percentile change between time periods less than -0.67 and more than 0.67 SD scores (SDSs), respectively. We applied multiple regression analyses, including conditional regression analyses, to account for correlations between repeated growth measures.

MEASUREMENTS AND MAIN RESULTS

Overall greater weight in the second and third trimesters, at birth, and at 12 months was associated with higher FEV₁ and FVC (range of z-score difference, 0.04-0.08, per SDS increase in weight). Greater weight at 3 months was associated with lower FEV₁/FVC and forced expiratory flow at 75% of the pulmonary volume (FEF_75%) (z-score differences [95% confidence interval]: -0.09 [-0.14 to -0.05] and -0.09 [-0.13 to -0.05] per SDS increase in weight, respectively). Restricted fetal weight growth was associated with lower childhood lung-function measures, partly depending on infant weight growth patterns (range of z-score difference, -0.25 to -0.13). Accelerated fetal weight growth was associated with higher FVC and lower FEV₁/FVC only if followed by accelerated infant weight growth. Fetal and infant weight growth was not associated with childhood asthma.

CONCLUSIONS

Both restricted fetal weight growth, partly depending on infant weight growth, and accelerated fetal and infant weight growth predispose children to lower lung function and a potential risk for respiratory diseases later in life.

Obesity and asthma: risk, control and treatment

Asthma and obesity are currently one of the most common diseases. Observing an increase in morbidity of obesity and asthma, it can be concluded that there is a link between these diseases. But the mechanism of this relation is not well known. Due to reduced movement in patients and treatment, asthma is conducive to obesity, and obesity can exacerbate the symptoms associated with asthma. Obesity can affect bronchial hyperresponsiveness. Increasing body fat in obese people leads to systemic inflammation and elevated serum levels of many proinflammatory cytokines (e.g. leptin) and anti-inflammatory ones (e.g. adiponectin) that can have a causal relationship to bronchial asthma, but human studies are ambiguous. Obese asthmatics are characterized by a phenotype: heavier asthma, worse response to treatment and control of asthma. It has been found that in obese people, weight loss reduces the severity of asthma symptoms, so in these patients, treatment should include weight control.

The effect of early growth patterns and lung function on the development of childhood asthma: a population based study

BACKGROUND

Infant weight gain is associated with lower lung function and a higher risk of childhood asthma. Detailed individual childhood growth patterns might be better predictors of childhood respiratory morbidity than the difference between two weight and height measurements. We assessed the associations of early childhood growth patterns with lung function and asthma at the age of 10 years and whether the child's current body mass index (BMI) influenced any association.

METHODS

We derived peak height and weight growth velocity, BMI at adiposity peak, and age at adiposity peak from longitudinally measured weight and height data in the first 3 years of life of 4435 children enrolled in a population-based prospective cohort study. At 10 years of age, spirometry was performed and current asthma was assessed by questionnaire. Spirometry outcomes included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), FEV₁/FVC ratio, and forced expiratory flow after exhaling 75% of vital capacity (FEF₇₅).

RESULTS

Greater peak weight velocity was associated with higher FVC but lower FEV₁/FVC and FEF₇₅. Greater BMI at adiposity peak was associated with higher FVC and FEV₁ but lower FEV₁/FVC and FEF₇₅. Greater age at adiposity peak was associated with higher FVC, FEV₁, FEV₁/FVC and FEF₇₅, particularly in children with a small size at birth, and lower odds of current asthma in boys. The child's current BMI only explained the associations of peak weight velocity and BMI at adiposity peak with FVC and FEV₁. Peak height velocity was not consistently associated with impaired lung function or asthma.

CONCLUSION

Peak weight velocity and BMI at adiposity peak were associated with reduced airway patency in relation to lung volume, whereas age at adiposity peak was associated with higher lung function parameters and lower risk of asthma at 10 years, particularly in boys.

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.

Body mass index status and peripheral airway obstruction in school-age children: a population-based cohort study

BACKGROUND

Few large prospective studies have investigated the impact of body mass index (BMI) on lung function during childhood.

METHODS

Using data collected between 2002 and 2013, we analysed associations between BMI status and lung function (assessed by spirometry) from 8 to 16 years, as well as cross-sectional associations with small airway function (impulse oscillometry) at 16 years in the BAMSE cohort (n=2889). At 16 years, cross-sectional associations with local and systemic inflammation were investigated by analysing FE_NO, blood eosinophils and neutrophils.

RESULTS

Overweight and obesity at 8 years were associated with higher FVC, but lower FEV₁/FVC ratio at 8 and 16 years. In boys, but not girls, obesity at 8 years was associated with a further reduction in FEV₁/FVC between 8 and 16 years. In cross-sectional analyses, overweight and obesity were associated with higher frequency dependence of resistance (R_5-20) and larger area under the reactance curve (AX^0.5) at 16 years. Increased blood neutrophil counts were seen in overweight and obese girls, but not in boys. No association was found between BMI status and FE_NO. Persistent, but not transient, overweight/obesity between 8 and 16 years was associated with higher R_5-20 and AX^0.5 and lower FEV₁/FVC (-2.8% (95% CI -4.1 to -1.2) in girls and -2.7% (95% CI -4.4 to -1.1) in boys) at 16 years, compared with persistent normal weight.

CONCLUSION

In childhood and adolescence, overweight and obesity, particularly persistent overweight, were associated with evidence of airway obstruction, including the small airways.

Respiratory allergies in the elderly: findings from the Korean Longitudinal Study on Health and Aging phase I study (2005-2006)

Population aging is a global issue, but is estimated to be more rapid and dramatic in Asian countries. In the past, allergy might have been a minor concern in the elderly (usually defined as ≥65 years). However, recent series of epidemiologic studies indicate that allergic diseases are more prevalent than expected in the aged population. Furthermore, they pose significant impact on quality of life and socioeconomic costs. The burden may also increase in the elderly, due to frequent comorbidities and treatment-related complications. The Korean Longitudinal Study on Health and Aging (KLoSHA) cohort study is one of major research projects on the epidemiology of common geriatric disease conditions in Korea. In this review, we summarized the baseline findings on the prevalence, risk factors, comorbidities and impact of geriatric respiratory allergic conditions in the phase I KLoSHA cohort study.

The effect of obesity, weight gain, and weight loss on asthma inception and control

PURPOSE OF REVIEW

There is ample and growing evidence that obesity increases the risk of asthma and morbidity from asthma. Here, we review recent clinical evidence supporting a causal link between obesity and asthma, and the mechanisms that may lead to 'obese asthma'.

RECENT FINDINGS

Although in some children obesity and asthma simply co-occur, those with 'obese asthma' have increased asthma severity, lower quality of life, and reduced medication response. Underlying mechanistic pathways may include anatomical changes of the airways such as obstruction and dysanapsis, systemic inflammation, production of adipokines, impaired glucose-insulin metabolism, altered nutrient levels, genetic and epigenetic changes, and alterations in the airway and/or gut microbiome. A few small studies have shown that weight loss interventions may lead to improvements in asthma outcomes, but thus far research on therapeutic interventions for these children has been limited.

SUMMARY

Obesity increases the risk of asthma - and worsens asthma severity or control - via multiple mechanisms. 'Obese asthma' is a complex, multifactorial phenotype in children. Obesity and its complications must be managed as part of the treatment of asthma in obese children.