Association of obesity with IgE levels and allergy symptoms in children and adolescents: results from the National Health and Nutrition Examination Survey 2005-2006

Pediatric Obesity and the Immune System

Obesity has reached pandemic proportion and represents a major risk for several comorbidities. In addition to metabolic and cardiovascular obesity-related diseases, recent evidence suggested that obesity might affect immune system function. Adipose tissue is considered an endocrine organ that actively secretes cytokines also referred to as "adipokines." Adipokines play an important role in the control of human metabolism. The dysfunctional adipose tissue in obese individuals is characterized by an altered cytokine secretion pattern that promotes chronic low-grade inflammation. Epidemiological evidence highlights the association between obesity and allergic and immune-mediated diseases, such as asthma, allergic rhinitis, rheumatic arthritis, and psoriasis. Less is known about underlying pathogenic mechanisms. However, several recent in vivo and in vitro studies have reported that adipokines are involved in inflammatory and autoimmune disorders by influencing both innate and acquired immune responses. In addition, obesity has been associated with reduced immune surveillance and increased risk of cancer. This paper reviews the evidence regarding the role of adipokines in immune system regulation, with particular emphasis on autoimmune, allergic, and inflammatory disorders. Understanding how obesity affects immune system functions may enable researchers to find new potential therapeutic targets in the management of allergic and autoimmune diseases.

Excess Free Fructose Beverages and Allergy in Children and Adolescents: Results From NHANES 2005-2006

PURPOSE

Our purpose was to investigate the relationship between intake of excess free fructose beverages and allergy among children and adolescents.

METHODS

We analyzed data of 860 children (aged 6 to 12 years) and 1,142 adolescents (aged 13 to 19 years) from the National Health and Nutrition Examination Survey 2005-2006. Logistic regression analyses were performed to determine the associations between consumption of excess free fructose beverages and allergic symptoms or allergic sensitization.

RESULTS

The pattern of findings was not entirely consistent, but some analyses supported the hypothesis of an association between intake of excess free fructose beverages and allergy. After controlling for the potential confounders, children who consumed nondiet fruit drinks at least 5 times per week had a nearly 2.5-fold greater odds of allergic sensitization than did those who consumed such drinks only 1 to 3 times per month (OR = 2.446; 95% CI, 1.583-3.780). Adolescents who consumed excess free fructose beverages at least 5 times per week or 1 to 4 times per week had about fivefold greater odds of presence of allergic symptoms than did those who seldom consumed these beverages (OR = 5.164; 95% CI, 1.866-14.297 and OR = 4.112; 95% CI, 1.857-9.107, respectively). Adolescents who consumed apple juice at least 5 times per week had a twofold greater odds of presence of allergic sensitization than did the seldom consumers (OR = 2.215; 95% CI, 1.178-4.164).

CONCLUSIONS

These findings provide some support for the hypothesis of a link between intake of excess free fructose beverages and allergic symptoms or allergic sensitization in children and adolescents.

Food Allergy in Children: An Overview

The estimated prevalence of food allergy amongst children in the west is around 6-8% but there is paucity of data in the Indian population. There is a complex interplay of environmental influences and genetic factors in the immuno-pathogenesis and manifestations of food allergy. A reliable thorough clinical history, combined with positive skin prick tests or food-specific IgE, is essential for a more precise diagnosis of food allergy. Currently there is no cure for food allergy. The management of food allergy usually includes strict avoidance, patient education and provision of emergency medication (adrenaline-autoinjectors). Emerging therapies based on evolving research are focused on a more active approach to management which includes early introduction of potentially allergenic foods, anticipatory testing and desensitisation to food allergens. Lack of food labelling policy and non availability of adrenaline auto-injectors is a huge limiting factor for effective management of food allergy among children in India. The present review focuses on IgE mediated food allergy.

Allergic sensitization at school age is a systemic low-grade inflammatory disorder

BACKGROUND

Systemic low-grade inflammation has been demonstrated in a range of the frequent noncommunicable diseases (NCDs) proposing a shared mechanism, but is largely unexplored in relation to allergic sensitization. We therefore aimed to investigate the possible association with childhood allergic sensitization.

METHODS

High-sensitivity C-reactive protein (hs-CRP), interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), and chemokine (C-X-C motif) ligand 8 (CXCL8) were measured in plasma at age 6 months (N = 214) and 7 years (N = 277) in children from the Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ (COPSAC₂₀₀₀ ) birth cohort. Allergic sensitization against common inhalant and food allergens was determined longitudinally at ages ½, 1½, 4 and 6 years by specific IgE assessments and skin prick tests. Associations between inflammatory biomarkers and sensitization phenotypes were tested with logistic regression and principal component analyses (PCAs).

RESULTS

Adjusted for gender, recent infections, and a CRP genetic risk score, hs-CRP at 7 years was associated with concurrent elevated specific IgE against any allergen [adjusted OR (aOR) = 1.40; 95% CI, 1.14-1.72; P = 0.001], aeroallergens (aOR, 1.43; 1.15-1.77; P = 0.001), food allergens (aOR, 1.31; 95% CI, 1.02-1.67; P = 0.04), sensitization without any clinical allergy symptoms (aOR = 1.40; 1.06-1.85; P = 0.02), and with similar findings for skin prick tests. The other inflammatory markers were not univariately associated with sensitization, but multiparametric PCA suggested a specific inflammatory response among sensitized children. Inflammatory markers at age 6 months were not associated with subsequent development of sensitization phenotypes.

CONCLUSIONS

Elevated hs-CRP is associated with allergic sensitization in school-aged children suggesting systemic low-grade inflammation as a phenotypic characteristic of this early-onset NCD.

Prevalence of Self-reported Allergic Diseases and IgE Levels: A 2010 KNHANES Analysis

PURPOSE

The prevalence of allergic diseases is known to be associated with both demographic and environmental factors. Herein, we aimed to determine significant factors associated with the prevalence of allergic diseases and with total immunoglobulin E (tIgE) and specific immunoglobulin E (sIgE) levels in Korea.

METHODS

We analyzed unweighted data collected by the 2010 Korea National Health and Nutrition Examination Survey for 2,342 subjects who underwent serum tests for tIgE and sIgE to Dermatophagoides farinae, dog, and Blattella germanica, representing a sample of 16,003,645 citizens, by considering the sample weight and stratification.

RESULTS

The overall prevalence of self-reported allergic diseases was 37.6%. The prevalence rates of allergic rhinitis and atopic dermatitis decreased with age, whereas the asthma prevalence was not affected by the age of the subjects. When analyzed according to the type of allergic diseases, the prevalence of self-reported allergic disease was significantly associated with various factors (e.g. age, occupation, living in urban areas, and depression). The tIgE level decreased with age, but later increased. Elevation of tIgE was significantly associated with male sex, type of occupation, obesity, and smoking status. However, the risk factors for the increased sIgE levels to each allergen were quite different. Sensitization to D. farinae was more likely in young subjects, whereas the prevalence of sensitization to B. germanica was significantly higher in subjects with male sex, residing in a house (houses), and with glucose intolerance. Finally, young age and the smoking status were significantly associated with sensitization to dog.

CONCLUSIONS

Various demographic and environmental factors were significantly associated with the prevalence of self-reported allergic diseases and the levels of tIgE and sIgE to D. farinae, B. germanica, and dog in Korea.

Obesity's effect on asthma extends to diagnostic criteria

BACKGROUND

The use of inflammatory biomarkers to delineate the type of lung inflammation present in asthmatic subjects is increasingly common. However, the effect of obesity on these markers is unknown.

OBJECTIVES

We aimed to determine the effect of obesity on conventional markers of inflammation in asthmatic subjects.

METHODS

We performed secondary analysis of data from 652 subjects previously enrolled in 2 Asthma Clinical Research Network trials. We performed linear correlations between biomarkers and logistic regression analysis to determine the predictive value of IgE levels, blood eosinophil counts, and fraction of exhaled nitric oxide values in relationship to sputum eosinophil counts (>2%), as well as to determine whether cut points existed that would maximize the sensitivity and specificity for predicting sputum eosinophilia in the 3 weight groups.

RESULTS

Overall, statistically significant but relatively weak correlations were observed among all 4 markers of inflammation. Within obese subjects, the only significant correlation found was between IgE levels and blood eosinophil counts (r = 0.33, P < .001); furthermore, all other correlations between inflammatory markers were approximately 0, including correlations with sputum eosinophil counts. In addition, the predictive value of each biomarker alone or in combination was poor in obese subjects. In fact, in obese subjects none of the biomarkers of inflammation significantly predicted the presence of high sputum eosinophil counts. Obese asthmatic subjects have lower cut points for IgE levels (268 IU), fraction of exhaled nitric oxide values (14.5 ppb), and blood eosinophil counts (96 cells/μL) than all other groups.

CONCLUSIONS

In obese asthmatic subjects conventional biomarkers of inflammation are poorly predictive of eosinophilic airway inflammation. As such, biomarkers currently used to delineate eosinophilic inflammation in asthmatic subjects should be approached with caution in these subjects.

Psychoneuroimmunoendocrinology: clinical implications

Psychoneuroimmunoendocrinology, which was first described in 1936, is the study of the interactions between the psyche, neural and endocrine functions and immune responses. The aim of psychoneuroimmunoendocrinology is to apply medical knowledge to the treatment of different allergic, immune, autoimmune, rheumatic, neoplastic, endocrine, cardiovascular and dental pathologies, among other disorders. Epigenetic factors and major stresses from different types of stimuli acting through distinct pathways and neurotransmitters are highly involved in altering the psychoneuroimmunoendocrine axis, resulting in the emergence of disease. The main purpose of this report is to expand the understanding of psychoneuroimmunoendocrinology and to demonstrate the importance of the above-mentioned interactions in the etiology of multiple pathologies. In this review, a search of the medical literature using PubMed (free access search engine for the Medline database of the National Library of Medicine of the United States) over the years 1936 to 2016 was conducted, and descriptive and experimental studies and reviews of the scientific literature were included.

Effects of infant weight gain on subsequent allergic outcomes in the first 3 years of life

Background

The association between early weight gain and later allergic outcomes has not been well studied. We examined the relation between weight gain and the subsequent development of allergic outcomes in the first 36 months of life in a Singapore birth cohort.

Methods

In repeated visits in the first 15 months, we measured infant weight and administered questionnaires ascertaining allergic outcomes. At ages 18 and 36 months, we administered skin prick tests (SPTs) to inhalant and food allergens.

Results

At 18 months, 13.5% had a positive SPT, 3.5% had wheeze and a positive SPT, 3.9% had rhinitis and a positive SPT, and 6.1% had eczema and a positive SPT. Higher weight gain from 6 to 9 months, 9 to 12 months and 12 to 15 months were independently associated with a reduced risk of developing a positive SPT at 18 months (p-trend ≤0.03). At 36 months, 23.5% had a positive SPT, 11.9% had wheeze and a positive SPT, 12.2% rhinitis and a positive SPT, and 11.5% eczema and a positive SPT. Higher weight gain from 12 to 15 months was associated with a reduced risk of developing a positive SPT at 36 months (p-trend <0.01). No significant associations were observed between weight gain in any period and wheeze, rhinitis or eczema combined with a positive SPT at 18 or 36 months.

Conclusion

Higher weight gain in the first 15 months of life was associated with a reduced risk of allergen sensitization, but not with combinations of allergic symptoms.

Trial registration

NCT01174875 Registered 1 July 2010, retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-017-0890-0) contains supplementary material, which is available to authorized users.

The influence of gender and atopy in the relationship between obesity and asthma in childhood

BACKGROUND

The objective of the study was to examine the relationship between asthma and overweight-obesity in Spanish children and adolescents and to determine whether this relationship was affected by gender and atopy.

METHODS

The study involves 8607 Spanish children and adolescents from the International Study of Asthma and Allergies in Childhood phase III. Unconditional logistic regression was used to obtain adjusted odds ratios (OR) and 95% confidence intervals (95% CI) for the association between asthma symptoms and overweight-obesity in the two groups. Afterwards, it was stratified by sex and rhinoconjunctivitis.

RESULTS

The prevalence of overweight and obesity in 6-7-year-old children was 18.6% and 5.2% respectively and in 13-14 year-old teenagers was 11.4% and 1.1% respectively. Only the obese children, not the overweight children, of the 6-7 year old group had a higher risk of any asthma symptoms (wheezing ever: OR 1.68 [1.15-2.47], asthma ever: OR 2.29 [1.43-3.68], current asthma 2.56 [1.54-4.28], severe asthma 3.18 [1.50-6.73], exercise-induced asthma 2.71 [1.45-5.05]). The obese girls had an increased risk of suffering any asthma symptoms (wheezing ever: OR 1.73 [1.05-2.91], asthma ever: OR 3.12 [1.67-5.82], current asthma 3.20 [1.65-6.19], severe asthma 4.83[1.94-12.04], exercise-induced asthma 3.68 [1.67-8.08]). The obese children without rhinoconjunctivitis had a higher risk of asthma symptoms.

CONCLUSIONS

Obesity and asthma symptoms were associated in 6-7 year-old children but not in 13-14 year-old teenagers. The association was stronger in non-atopic children and obese girls.

Food Allergies

Food allergies are common and seem to be increasing in prevalence. Preventive measures have become far more evident in the public arena (schools, camps, sports venues, and so forth). Evaluation and management of food allergies has evolved such that primary care practitioners may choose to provide initial diagnostic and treatment care or refer to allergists for similar care. Food allergies, once considered incurable, are now being diminished in intensity by new strategies.

Prevention of food allergy

The past few decades have witnessed an increase in the prevalence of IgE-mediated food allergy (FA). For prevention strategies to be effective, we need to understand the causative factors underpinning this rise. Genetic factors are clearly important in the development of FA, but given the dramatic increase in prevalence over a short period of human evolution, it is unlikely that FA arises through germline genetic changes alone. A plausible hypothesis is that 1 or more environmental exposures, or lack thereof, induce epigenetic changes that result in interruption of the default immunologic state of tolerance. Strategies for the prevention of FA might include primary prevention, which seeks to prevent the onset of IgE sensitization; secondary prevention, which seeks to interrupt the development of FA in IgE-sensitized children; and tertiary prevention, which seeks to reduce the expression of end-organ allergic disease in children with established FA. This review emphasizes the prevention of IgE-mediated FA through dietary manipulation, among other strategies; in particular, we focus on recent interventional studies in this field.

Prevalence and comorbidities in adults with psoriasis compared to atopic eczema

BACKGROUND

Most data suggesting an association between psoriasis and cardiovascular disease (CVD) have come from specialized populations at either low or high risk of CVD. Atopic dermatitis (AD) has been associated with a number of modifiable risk factors, particularly obesity. There has been a recent controversy on the suggestion that associations with comorbidities in psoriasis may be due to overreporting or biased by disease severity and therefore not necessarily representative of the general psoriasis population.

OBJECTIVES

To evaluate the prevalence of AD and psoriasis and to compare the prevalence rates of comorbidities based on a large sample of health insurance data.

METHODS

Data were collected from a database of non-selected individuals from a German statutory health insurance organization that covers all geographic regions. Individuals identified by International Classification of Diseases (ICD)-10 codes applied to all outpatient and inpatient visits in the year 2009. Comorbidities were evaluated by ICD-10 diagnoses.

RESULTS

The database consisted of 1 642 852 members of a German statutory health insurance. Of 1 349 671 data sets analyzed, 37 456 patients ≥18 years were diagnosed with psoriasis (prevalence 2.78%), and 48 140 patients ≥18 years of age were diagnosed with AD, equivalent to a prevalence of 3.67%. Patients with psoriasis showed increased rates of comorbidities in all age groups. Comorbidities related to the metabolic syndrome including arterial hypertension [prevalence ratio (PR), 1.94; 95% confidence interval (CI), 1.90-1.98], hyperlipidaemia (PR, 1.77; 95% CI, 1.73-1.81), obesity (PR, 1.74; 95% CI, 1.69-1.79) and diabetes mellitus (PR, 1.88; 95% CI, 1.83-1.94) were significantly more common among patients with psoriasis compared to AD.

CONCLUSIONS

Diseases forming part of the metabolic syndrome showed significant lower prevalence rates in patients with AD than in patients with psoriasis. Within the limitations of secondary healthcare data, our study disproves the suggestion that associations with comorbidities in psoriasis may be biased by a higher degree of severity or overreporting.

High Fat Diet Inhibits Dendritic Cell and T Cell Response to Allergens but Does Not Impair Inhalational Respiratory Tolerance

The incidence of obesity has risen to epidemic proportions in recent decades, most commonly attributed to an increasingly sedentary lifestyle, and a ‘western’ diet high in fat and low in fibre. Although non-allergic asthma is a well-established co-morbidity of obesity, the influence of obesity on allergic asthma is still under debate. Allergic asthma is thought to result from impaired tolerance to airborne antigens, so-called respiratory tolerance. We sought to investigate whether a diet high in fats affects the development of respiratory tolerance. Mice fed a high fat diet (HFD) for 8 weeks showed weight gain, metabolic disease, and alteration in gut microbiota, metabolites and glucose metabolism compared to age-matched mice fed normal chow diet (ND). Respiratory tolerance was induced by repeated intranasal (i.n.) administration of ovalbumin (OVA), prior to induction of allergic airway inflammation (AAI) by sensitization with OVA in alum i.p. and subsequent i.n. OVA challenge. Surprisingly, respiratory tolerance was induced equally well in HFD and ND mice, as evidenced by decreased lung eosinophilia and serum OVA-specific IgE production. However, in a pilot study, HFD mice showed a tendency for impaired activation of airway dendritic cells and regulatory T cells compared with ND mice after induction of respiratory tolerance. Moreover, the capacity of lymph node cells to produce IL-5 and IL-13 after AAI was drastically diminished in HFD mice compared to ND mice. These results indicate that HFD does not affect the inflammatory or B cell response to an allergen, but inhibits priming of Th2 cells and possibly dendritic cell and regulatory T cell activation.

Pediatric Obesity-Related Asthma: The Role of Metabolic Dysregulation

The burden of obesity-related asthma among children, particularly among ethnic minorities, necessitates an improved understanding of the underlying disease mechanisms. Although obesity is an independent risk factor for asthma, not all obese children develop asthma. Several recent studies have elucidated mechanisms, including the role of diet, sedentary lifestyle, mechanical fat load, and adiposity-mediated inflammation that may underlie the obese asthma pathophysiology. Here, we review these recent studies and emerging scientific evidence that suggest metabolic dysregulation may play a role in pediatric obesity-related asthma. We also review the genetic and epigenetic factors that may underlie susceptibility to metabolic dysregulation and associated pulmonary morbidity among children. Lastly, we identify knowledge gaps that need further exploration to better define pathways that will allow development of primary preventive strategies for obesity-related asthma in children.

Obesity is a risk factor for allergic rhinitis in children of Wuhan (China)

Background

The relationship between obesity and allergic diseases in children of China is unclear.

Objective

To analysis the relationship between obesity and overweight and the prevalence of allergic diseases and the impact of gender.

Methods

Questionnaire based on those used in National Study of Asthma and Allergies in Childhood in China. The study included 3,327 participants (23.7% aged 2–6 years, 65.8% aged 7–12 years, 10.5% aged 13–14 years) in Wuhan City. Allergic diseases were determined by physicians.

Results

Overweight was found in 35.68% of participants (8.96% of 2–6 years old, 32.83% of 7–12 years old, and 48.57% of 13–14 years old), obesity in 12.53% (4.18%, 12.01%, and 4.29%, respectively). Obesity (odds ratio [OR], 1.33) increased the prevalence of allergic rhinitis and atopic dermatitis. Obesity (OR, 1.48) affected the incidence of allergic rhinitis in girls. There was no relationship between body mass index (BMI) and asthma in child from Wuhan City. Obesity and overweight did not affect the frequency of asthma, food allergy, and drug allergy.

Conclusion

Obesity increased the prevalence of allergic rhinitis and atopic dermatitis in child. Higher BMI was no relationship with the prevalence of asthma, food allergy, and drug allergy.

Impact of Obesity and Metabolic Syndrome on Immunity

Obesity is associated with metabolic disturbances that cause tissue stress and dysfunction. Obese individuals are at a greater risk for chronic disease and often present with clinical parameters of metabolic syndrome (MetS), insulin resistance, and systemic markers of chronic low-grade inflammation. It has been well established that cells of the immune system play an important role in the pathogenesis of obesity- and MetS-related chronic diseases, as evidenced by leukocyte activation and dysfunction in metabolic tissues such as adipose tissue, liver, pancreas, and the vasculature. However, recent findings have highlighted the substantial impact that obesity and MetS parameters have on immunity and pathogen defense, including the disruption of lymphoid tissue integrity; alterations in leukocyte development, phenotypes, and activity; and the coordination of innate and adaptive immune responses. These changes are associated with an overall negative impact on chronic disease progression, immunity from infection, and vaccine efficacy. This review presents an overview of the impact that obesity and MetS parameters have on immune system function.

Impact of Obesity and Metabolic Syndrome on Immunity

Obesity is associated with metabolic disturbances that cause tissue stress and dysfunction. Obese individuals are at a greater risk for chronic disease and often present with clinical parameters of metabolic syndrome (MetS), insulin resistance, and systemic markers of chronic low-grade inflammation. It has been well established that cells of the immune system play an important role in the pathogenesis of obesity- and MetS-related chronic diseases, as evidenced by leukocyte activation and dysfunction in metabolic tissues such as adipose tissue, liver, pancreas, and the vasculature. However, recent findings have highlighted the substantial impact that obesity and MetS parameters have on immunity and pathogen defense, including the disruption of lymphoid tissue integrity; alterations in leukocyte development, phenotypes, and activity; and the coordination of innate and adaptive immune responses. These changes are associated with an overall negative impact on chronic disease progression, immunity from infection, and vaccine efficacy. This review presents an overview of the impact that obesity and MetS parameters have on immune system function.

Pathophysiology of Food Allergy

Food allergy is a growing public health problem that is estimated to affect 4% to 8% of children and 5% of adults. In this review, we discuss our current understanding of the pathophysiology of food allergy, from oral tolerance, to sensitization, and lastly the elicitation of an allergic response. As much of the existing evidence for the mechanisms of food allergy is derived from animal models, we include these studies where relevant. In addition, whenever possible, we review similar evidence involved in human disease and provide applications for consideration in clinical practice.

Allergy associations with the adult fecal microbiota: Analysis of the American Gut Project

BACKGROUND

Alteration of the gut microbial population (dysbiosis) may increase the risk for allergies and other conditions. This study sought to clarify the relationship of dysbiosis with allergies in adults.

METHODS

Publicly available American Gut Project questionnaire and fecal 16S rRNA sequence data were analyzed. Fecal microbiota richness (number of observed species) and composition (UniFrac) were used to compare adults with versus without allergy to foods (peanuts, tree nuts, shellfish, other) and non-foods (drug, bee sting, dander, asthma, seasonal, eczema). Logistic and Poisson regression models adjusted for potential confounders. Odds ratios and 95% confidence intervals (CI) were calculated for lowest vs highest richness tertile. Taxonomy associations considered 122 non-redundant taxa (of 2379 total taxa) with ≥ 0.1% mean abundance.

RESULTS

Self-reported allergy prevalence among the 1879 participants (mean age, 45.5 years; 46.9% male) was 81.5%, ranging from 2.5% for peanuts to 40.5% for seasonal. Fecal microbiota richness was markedly lower with total allergies (P = 10(-9)) and five particular allergies (P ≤ 10(-4)). Richness odds ratios were 1.7 (CI 1.3-2.2) with seasonal, 1.8 (CI 1.3-2.5) with drug, and 7.8 (CI 2.3-26.5) with peanut allergy. These allergic participants also had markedly altered microbial community composition (unweighted UniFrac, P = 10(-4) to 10(-7)). Total food and non-food allergies were significantly associated with 7 and 9 altered taxa, respectively. The dysbiosis was most marked with nut and seasonal allergies, driven by higher Bacteroidales and reduced Clostridiales taxa.

INTERPRETATION

American adults with allergies, especially to nuts and seasonal pollen, have low diversity, reduced Clostridiales, and increased Bacteroidales in their gut microbiota. This dysbiosis might be targeted to improve treatment or prevention of allergy.

Deficiency of FcϵR1 Increases Body Weight Gain but Improves Glucose Tolerance in Diet-Induced Obese Mice

Prior studies demonstrated increased plasma IgE in diabetic patients, but the direct participation of IgE in diabetes or obesity remains unknown. This study found that plasma IgE levels correlated inversely with body weight, body mass index, and body fat mass among a population of randomly selected obese women. IgE receptor FcϵR1-deficient (Fcer1a(-/-)) mice and diet-induced obesity (DIO) mice demonstrated that FcϵR1 deficiency in DIO mice increased food intake, reduced energy expenditure, and increased body weight gain but improved glucose tolerance and glucose-induced insulin secretion. White adipose tissue from Fcer1a(-/-) mice showed an increased expression of phospho-AKT, CCAAT/enhancer binding protein-α, peroxisome proliferator-activated receptor-γ, glucose transporter-4 (Glut4), and B-cell lymphoma 2 (Bcl2) but reduced uncoupling protein 1 (UCP1) and phosphorylated c-Jun N-terminal kinase (JNK) expression, tissue macrophage accumulation, and apoptosis, suggesting that IgE reduces adipogenesis and glucose uptake but induces energy expenditure, adipocyte apoptosis, and white adipose tissue inflammation. In 3T3-L1 cells, IgE inhibited the expression of CCAAT/enhancer binding protein-α and peroxisome proliferator-activated receptor-γ, and preadipocyte adipogenesis and induced adipocyte apoptosis. IgE reduced the 3T3-L1 cell expression of Glut4, phospho-AKT, and glucose uptake, which concurred with improved glucose tolerance in Fcer1a(-/-) mice. This study established two novel pathways of IgE in reducing body weight gain in DIO mice by suppressing adipogenesis and inducing adipocyte apoptosis while worsening glucose tolerance by reducing Glut4 expression, glucose uptake, and insulin secretion.

Obesity and atopy

The prevalence of obesity has increased worldwide, and weight gain has been shown to influence the development and clinical expression of various conditions including asthma. The relationships between atopy and obesity remain uncertain, both in adults and in children. Although there are physiopathologic mechanisms which could explain how obesity could influence the immune system and promote the process of sensitization, evidences in favour of a possible role of obesity on the development of atopy have been inconsistent. Furthermore, the bulk of evidence suggests that atopy does not mediate the relationship between obesity and asthma, although in some populations, particularly in children and women, such association has been reported. Such lack of relationship has also been found with rhinoconjunctivitis although it has been observed for atopic dermatitis. Several factors may explain these variable results, including populational or environmental characteristics, socioeconomic status, confounding factors, in addition to sample size, and methodology of the performed studies. The possibility that obesity influences atopy through its effects on sex hormones is suggested by a more frequent link between atopy and obesity in women, particularly postpuberal. Further research should be conducted on the influence of weight gain on atopy and atopic diseases.

Metabolic origins of childhood asthma

Childhood obesity and incidence of asthma are increasing globally. The parallel increase of the two suggests that obesity and asthma may be related and that abnormalities in the lipid and/or glucose metabolism may contribute to the pathogenesis of asthma. The clinical presentation of obese asthma is distinct from other asthma phenotypes and depending on age of onset of symptoms. Asthma in obese people tends to be more severe, not typically associated with allergy, and less responsive to standard anti-inflammatory therapy, including corticosteroids. Obesity and obesity-related comorbidities may lead to asthma via a number of mechanisms including changes in lung mechanics, the nitric oxide metabolism, and by causing inflammation. Furthermore, evidence suggests that nutrition during pregnancy contributes to intrauterine immune and metabolic programming in the offspring, which may have major influences on predisposition to cardiovascular, metabolic, and allergic diseases, including asthma, later in life. This review will highlight some suggested mechanistic links between obesity and diabetes with asthma.

The mediating effect of body mass index on the relationship between cigarette smoking and atopic sensitization in Chinese adults

BACKGROUND

It is unclear whether the relationship between cigarette smoking and atopy is mediated by body fat mass, such as the Body Mass Index (BMI). We assessed the mediating role of BMI on the relationship between smoking and atopy in Chinese adults.

METHODS

A hospital-based case-control study of 786 atopic cases and 2771 controls was conducted in adults aged 18 years or older from March 2010 to September 2014 in Harbin, China. Mediation models were used to estimate the indirect effects of smoking on atopic sensitization through BMI.

RESULTS

Compared to non-smokers, light smokers and moderate smokers had a lower risk of inhalant allergen sensitization. The indirect effect of smoking and sensitization to aeroallergens were only observed in light smokers (point estimate, -0.026; 95% CI, -0.062 to -0.004). The mediating roles of BMI on the relationships between smoking and other types of allergic sensitization were not statistically significant.

CONCLUSION

BMI appeared to partially mediate the effect of light smoking on sensitization to aeroallergens. However, considering the other harmful health effects of cigarette smoking, the effective method to lower the incidence of atopy would be to decrease body fat mass by physical exercise and employing other more healthy ways of living rather than smoking.

Schistosome infection is negatively associated with mite atopy, but not wheeze and asthma in Ghanaian schoolchildren

BACKGROUND

Epidemiological evidence suggests that helminth infection and rural living are inversely associated with allergic disorders.

OBJECTIVE

The aim of the study was to investigate the effect of helminth infections and urban versus rural residence on allergy in schoolchildren from Ghana.

METHODS

In a cross-sectional study of 1385 children from urban-high socio-economic status (SES), urban-low SES and rural schools, associations between body mass index (BMI), allergen-specific IgE (sIgE), parasitic infections and allergy outcomes were analysed. Allergy outcomes were skin prick test (SPT) reactivity, reported current wheeze and asthma.

RESULTS

Helminth infections were found predominantly among rural subjects, and the most common were hookworm (9.9%) and Schistosoma spp (9.5%). Being overweight was highest among urban-high SES (14.6%) compared to urban-low SES (5.5%) and rural children (8.6%). The prevalence of SPT reactivity to any allergen was 18.3%, and this was highest among rural children (21.4%) followed by urban-high SES (20.2%) and urban-low SES (10.5%) children. Overall, SPT reactivity to mite (12%) was most common. Wheeze and asthma were reported by 7.9% and 8.3%, respectively. In multivariate analyses, factors associated with mite SPT were BMI (aOR 2.43, 95% CI 1.28-4.60, P = 0.007), schistosome infection (aOR 0.15, 95% CI 0.05-0.41) and mite sIgE (aOR 7.40, 95% CI 5.62-9.73, P < 0.001) but not area. However, the association between mite IgE and SPT differed by area and was strongest among urban-high SES children (aOR = 15.58, 95% CI 7.05-34.43, P < 0.001). Compared to rural, urban-low SES area was negatively associated with current wheeze (aOR 0.41, 95% CI 0.20-0.83, P = 0.013). Both mite sIgE and mite SPT were significantly associated with current wheeze and asthma.

CONCLUSION AND CLINICAL RELEVANCE

Infection with schistosomes appeared to protect against mite SPT reactivity. This needs to be confirmed in future studies, preferably in a longitudinal design where schistosome infections are treated and allergic reactions reassessed.

Effect modification by gender and smoking status on the association between obesity and atopic sensitization in Chinese adults: a hospital-based case-control study

BACKGROUND

There is an ongoing debate on the potential association between obesity and atopy. However, no previous studies have investigated whether this relationship depends on sex and smoking status in Chinese adults.

METHODS

In this hospital-based, case-control study, we recruited 1150 atopic cases aged 18 years or older and 1245 healthy control participants during April 2009 and December 2012 in Harbin, China. We conducted structured questionnaire interviews, anthropometry measurements and serum allergen-specific immunoglobulin E (IgE) testing. Univariate and multivariate logistic regression models were used to explore the relationship between obesity and atopy risk stratified by sex and smoking status.

RESULTS

There was an association between obesity and an increased risk of atopic sensitization after adjusting for age, educational, family history, smoking and alcohol consumption (OR: 2.61, 3.25; 95% CI: 1.57-4.33,1.91-5.56 in males and females, respectively). The association between BMI and allergic sensitization depended on smoking status. In both genders, the association of obesity with atopic sensitization risk was stronger in non-smokers than in current smokers. In males, ORs of atopic sensitization for obesity were 3.15 (95% CI, 1.46-6.68) for non-smokers and 2.22 (95% CI, 1.10-4.48) for current smokers. The corresponding ORs in females were 3.51 (95% CI, 1.98-6.24) and 2.22 (95% CI, 0.46-10.68) for non-smokers and current smokers, respectively. After excluding those subjects who with pre-existing allergic conditions, the same relationship still remained.

CONCLUSIONS

Obesity is positively and significantly associated with the risk of atopy in both men and women as well in both smokers and non-smokers in China. In addition, the relationship between obesity and atopic sensitization is stronger in non-smokers than in current smokers.

Infant feeding practices and reported food allergies at 6 years of age

OBJECTIVE

The goal of this study was to identify the frequency of physician-diagnosed food allergies among 6-year-old US children and study the impact of exclusive breastfeeding and complementary food introduction on this frequency.

METHODS

Data were analyzed from children who participated in the Infant Feeding Practices Study II Year 6 Follow-Up Study (Y6FU). Children with probable food allergy (pFA) were defined as children with report of physician-diagnosed food allergy at age 6 years. Subgroups of pFA included children who were not diagnosed before 1 year of age (new pFA) and those with atopic risk factors (high risk).

RESULTS

Prevalence of total pFA in the Y6FU was 6.34%. The majority of these children had new pFA and high-risk factors. Higher maternal education, higher family income, family history of food allergy, and reported eczema before 1 year of age were significantly associated with higher odds of total or new pFA. Exclusive breastfeeding duration and timing of complementary food introduction were not significantly associated with total pFA. However, exclusive breastfeeding of ≥4 months compared with no breastfeeding was marginally associated with lower odds of new pFA (adjusted odds ratio: 0.51; P = .07); this effect was not observed with high-risk children.

CONCLUSIONS

Analysis of infant and maternal variables in the Y6FU cohort of US children revealed that socioeconomic and atopic factors were the main predictors of pFA at age 6 years. Exclusive breastfeeding of ≥4 months may have a preventive effect on development of pFA after 1 year of age in non high-risk children.

Nutritional influences on epigenetic programming: asthma, allergy, and obesity

Observational studies show consistent links between early-life nutritional exposures as important risk factors for the development of asthma, allergy, and obesity. Reliance on increasing use of dietary supplementation and fortification (eg, with folate) to compensate for increased consumption of processed foods is also influencing immune and metabolic outcomes. Epigenetics is providing substantial advances in understanding how early-life nutritional exposures can effect disease development. This article summarizes current evidence linking the influence of early-life nutritional exposures on epigenetic regulation with a focus on the disease outcomes of asthma, allergy, and obesity.

Role of cellular immunity in cow's milk allergy: pathogenesis, tolerance induction, and beyond

Food allergy is an aberrant immune-mediated reaction against harmless food substances, such as cow's milk proteins. Due to its very early introduction, cow's milk allergy is one of the earliest and most common food allergies. For this reason cow's milk allergy can be recognized as one of the first indications of an aberrant inflammatory response in early life. Classically, cow's milk allergy, as is true for most other allergies as well, is primarily associated with abnormal humoral immune responses, that is, elevation of specific immunoglobulin E levels. There is growing evidence indicating that cellular components of both innate and adaptive immunity play significant roles during the pathogenesis of cow's milk allergy. This is true for the initiation of the allergic phenotype (stimulation and skewing towards sensitization), development and outgrowth of the allergic disease. This review discusses findings pertaining to roles of cellular immunity in allergic inflammation, and tolerance induction against cow's milk proteins. In addition, a possible interaction between immune mechanisms underlying cow's milk allergy and other types of inflammation (infections and noncommunicable diseases) is discussed.

Obesity and adiposity indicators, asthma, and atopy in Puerto Rican children

BACKGROUND

Whether adiposity indicators other than body mass index (BMI) should be used in studies of childhood asthma is largely unknown. The role of atopy in "obese asthma" is also unclear.

OBJECTIVES

To examine the relationship among adiposity indicators, asthma, and atopy in Puerto Rican children, and to assess whether atopy mediates the obesity-asthma association.

METHODS

In a study of Puerto Rican children with (n = 351) and without (n = 327) asthma, we measured BMI, percent of body fat, waist circumference, and waist-to-hip ratio. The outcomes studied included asthma, lung function, measures of atopy, and, among cases, indicators of asthma severity or control. We performed mediation analysis to assess the contribution of atopy to the relationship between adiposity and asthma.

RESULTS

BMI, percent of body fat, and waist circumference were associated with increased odds of asthma. Among cases, all 3 measures were generally associated with lung function, asthma severity/control, and atopy; however, there were differences depending on the adiposity indicator analyzed. Atopy considerably mediated the adiposity-asthma association in this population: allergic rhinitis accounted for 22% to 53% of the association with asthma, and sensitization to cockroach mediated 13% to 20% of the association with forced vital capacity and 29% to 42% of the association with emergency department visits for asthma.

CONCLUSIONS

Adiposity indicators are associated with asthma, asthma severity/control, and atopy in Puerto Rican children. Atopy significantly mediates the effect of adiposity on asthma outcomes. Longitudinal studies are needed to further investigate the causal role, if any, of adiposity distribution and atopy on "obese asthma" in childhood.

Obesity--a risk factor for asthma, but not for atopic dermatitis, allergic rhinitis and sensitization

OBJECTIVE

To analyse the relationship between obesity and overweight and the prevalence of allergic diseases and sensitization, and the impact of gender and place of residence.

DESIGN

Questionnaire based on those used in ISAAC (International Study of Asthma and Allergies in Childhood) and ECRHS (European Community Respiratory Health Survey).

SETTING

Our study involved populations of the eight largest cities and one rural region in Poland (each with over 150,000 inhabitants).

SUBJECTS

The study included 18,617 participants (24·2% aged 6-7 years, 25·4% aged 13-14 years, 50·4% adults aged 20-44 years) in eight cities and one rural area. The out-patient study involved 4783 patients (25·7%); we performed skin prick testing with fifteen aeroallergens.

RESULTS

Overweight was found in 16·13% of participants (9·11% of 6-7-year-olds, 4·90% of 13-14-year-olds and 25·61% of adults), obesity in 6·41% (7·16%, 2·45% and 8·36%, respectively). In adults, overweight (OR=1·34) and obesity (OR=1·80) increased the prevalence of asthma, especially in women (OR=1·53, OR=2·01). Among 13-14-year-olds the prevalence was higher only in the obese (OR=1·76). Overweight (OR=1·99) and obesity (OR=2·17) affected the incidence of doctor-diagnosed asthma in 6-7-year-olds. Overweight (OR=0·81) and obesity (OR=0·76) reduced the prevalence of allergic rhinitis in men. There was no relationship between BMI and asthma in people from rural areas. Obesity and overweight did not affect the frequency of sensitization to aeroallergens.

CONCLUSIONS

Overweight and obesity increased the prevalence of symptomatic asthma in adults, especially in women. In 13-14-year-olds, only obesity increased the prevalence of asthma. In children, overweight was associated with increased prevalence of clinically diagnosed and declared asthma and a trend towards atopy. Higher BMI was negatively associated with the prevalence of allergic rhinitis in overweight and obese man. There was no correlation between BMI and sensitization to aeroallergens.

Peripheral blood leucocyte subclasses as potential biomarkers of adipose tissue inflammation and obesity subphenotypes in humans

While obesity is clearly accepted as a major risk factor for cardio-metabolic morbidity, it is also apparent that some obese patients largely escape this association, forming a unique obese subphenotype(s). Current approaches to define such subphenotypes include clinical biomarkers that largely reflect already manifested comorbidities, such as markers of dyslipidaemia, hyperglycaemia and impaired regulation of vascular tone, and anthropometric or imaging-based assessment of adipose tissue distribution. Low-grade inflammation, evident both systemically and within adipose tissue (particularly intra-abdominal fat depots), seems to characterize the more cardio-metabolically morbid forms of obesity. Indeed, several systemic inflammatory markers (C-reactive protein), adipokines (retinol-binding protein 4, adiponectin) and cytokines have been shown to correlate in humans with adipose tissue inflammation and with obesity-associated health risks. Circulating leucocytes constitute a diverse group of cells that form a major arm of the immune system. They are both major sources of cytokines and likely also of infiltrating adipose tissue immune cells in obesity. In the present review, we summarize currently available literature on 'classical' blood white cell classes and on more specific leucocyte subclasses present in the circulation in human obesity. We critically raise the possibility that leucocytes may constitute clinically available markers for the more morbidity-associated obesity subphenotype(s), and when available, for intra-abdominal adipose tissue inflammation.

Disease prevention in the age of convergence - the need for a wider, long ranging and collaborative vision

It is time to bring our imagination, creativity and passion to the fore in solving the global challenges of our age. Our global health crisis and the pandemic of noncommunicable diseases (NCDs) is clearly rooted in complex modern societal and environmental changes, many of which have effects on developing immune and metabolic responses. It is intimately related to wider environmental challenges. And it is unsurprising that many NCDs share similar risk factors and that many are associated with a rising predisposition for inflammation. Allergy is one of the earliest signs of environmental impact on these biological pathways, and may also offer an early barometer to assess the effects of early interventions. There is dawning awareness of how changing microbial diversity, nutritional patterns, sedentary indoor behaviours and modern pollutants adversely affect early metabolic and immune development, but still much to understand the complexity of these interactions. Even when we do harness the science and technology, these will not provide solutions unless we also address the wider social, cultural and economic determinants of health - addressing the interconnections between human health and the health of our environment. Now more than ever, we need a wider vision and a greater sense of collective responsibility. We need long-range approaches that aim for life long benefits of a 'healthier start to life', and stronger cross-sectoral collaborations to prevent disease. We need to give both our hearts and our minds to solving these global issues.

Influence of health behaviours on the incidence of infection and allergy in adolescents: the AFINOS cross-sectional study

BACKGROUND

Some health behaviours are liable to affect the incidence of allergies and/or common infections in young people; however, the extent and ways in which these might occur are mostly unknown. This study examines the association of health behaviours related to physical activity, sedentariness, diet and sleep with allergy and infection symptoms in adolescents, and also with biological markers that might mediate disease incidence.

METHODS

The study comprised a total of 2054 adolescents (50.7% girls) from the Madrid region of Spain. The incidence of infection and allergy symptoms three months prior to the study was obtained from a self-administered questionnaire. Physical and sedentary activities, height and weight, food habits and sleep duration were also self-reported and their influence on infection and allergy incidence was assessed by logistic regression analysis. Blood biomarkers (IgE, eosinophil percentage, leptin, interleukin (IL)-2, IL-4, IL-5 and IL-10) were evaluated in a subsample of 198 subjects.

RESULTS

Adequate sleep duration (OR = 0.79, 95%CI: 0.64 to 0.97) and unhealthy weight status (overweight/obesity) (OR = 1.35, 95%CI: 1.04-1.74) were independently associated with decreased and increased allergy incidence, respectively. No significant association was observed with infection incidence. IgE and leptin differed between adolescents with and without allergy symptoms. In regression models IgE was significantly associated with inadequate sleep duration and leptin with weight status.

CONCLUSION

Excess weight and inadequate sleep duration are independently associated with the incidence of allergy symptoms in adolescents. Adequate sleep duration and weight during adolescence might be relevant for a decreased risk of suffering allergy symptoms.

Allergic disease is associated with epilepsy in childhood: a US population-based study

BACKGROUND

Previous studies using animal models suggest an association between allergic disease and epilepsy. We sought to determine whether allergic disease is associated with epilepsy in children.

METHODS

We used the 2007-2008 National Survey of Children's Health, a US population-based study of 91 642 children aged 0-17 years to determine the association between the prevalence of epilepsy and allergic disease, including asthma, atopic dermatitis (AD)/eczema, hay fever, and food allergies. Multivariate logistic regression models were constructed that controlled for confounding variables.

RESULTS

The US lifetime prevalence of childhood epilepsy was 1.03% and was significantly associated with older age, male sex, lower household income, family structure and history of brain injury or concussion. Children with ≥1 allergic disease had more epilepsy in their lifetime than nonallergic children (logistic regression, adjusted odds ratio [95% confidence interval] = 1.79 [1.37-2.33]). Lifetime prevalence (2.30 [1.50-3.52]) and one-year prevalence of asthma (2.00 [1.41-2.84]), AD/eczema (1.73 [1.17-2.56]), hay fever (1.93 [1.41-2.65]) and food allergies (2.69 [1.38-4.01]) were associated with increased odds of ever being diagnosed with epilepsy. Similar results were found for current history of epilepsy. Severe AD/eczema (3.89 [1.34-11.32]) [corrected] and hay fever (2.46 [1.11-5.41]) were associated with even higher odds of epilepsy compared with mild/moderate disease. As the number of allergic diseases increased, so did the odds of lifetime history and current history of epilepsy.

CONCLUSIONS

The US prevalence of epilepsy is associated with allergic diseases in children. Further studies are needed to determine whether allergic inflammation contributes toward epileptogenesis.

Food allergy: Epidemiology, pathogenesis, diagnosis, and treatment

This review focuses on advances and updates in the epidemiology, pathogenesis, diagnosis, and treatment of food allergy over the past 3 years since our last comprehensive review. On the basis of numerous studies, food allergy likely affects nearly 5% of adults and 8% of children, with growing evidence of an increase in prevalence. Potentially rectifiable risk factors include vitamin D insufficiency, unhealthful dietary fat, obesity, increased hygiene, and the timing of exposure to foods, but genetics and other lifestyle issues play a role as well. Interesting clinical insights into pathogenesis include discoveries regarding gene-environment interactions and an increasing understanding of the role of nonoral sensitizing exposures causing food allergy, such as delayed allergic reactions to carbohydrate moieties in mammalian meats caused by sensitization from homologous substances transferred during tick bites. Component-resolved diagnosis is being rapidly incorporated into clinical use, and sophisticated diagnostic tests that indicate severity and prognosis are on the horizon. Current management relies heavily on avoidance and emergency preparedness, and recent studies, guidelines, and resources provide insight into improving the safety and well-being of patients and their families. Incorporation of extensively heated (heat-denatured) forms of milk and egg into the diets of children who tolerate these foods, rather than strict avoidance, represents a significant shift in clinical approach. Recommendations about the prevention of food allergy and atopic disease through diet have changed radically, with rescinding of many recommendations about extensive and prolonged allergen avoidance. Numerous therapies have reached clinical trials, with some showing promise to dramatically alter treatment. Ongoing studies will elucidate improved prevention, diagnosis, and treatment.

Mucosal immunology of food allergy

Food allergies are increasing in prevalence at a higher rate than can be explained by genetic factors, suggesting a role for as yet unidentified environmental factors. In this review, we summarize the state of knowledge about the healthy immune response to antigens in the diet and the basis of immune deviation that results in immunoglobulin E (IgE) sensitization and allergic reactivity to foods. The intestinal epithelium forms the interface between the external environment and the mucosal immune system, and emerging data suggest that the interaction between intestinal epithelial cells and mucosal dendritic cells is of particular importance in determining the outcome of immune responses to dietary antigens. Exposure to food allergens through non-oral routes, in particular through the skin, is increasingly recognized as a potentially important factor in the increasing rate of food allergy. There are many open questions on the role of environmental factors, such as dietary factors and microbiota, in the development of food allergy, but data suggest that both have an important modulatory effect on the mucosal immune system. Finally, we discuss recent developments in our understanding of immune mechanisms of clinical manifestations of food allergy. New experimental tools, particularly in the field of genomics and the microbiome, are likely to shed light on factors responsible for the growing clinical problem of food allergy.

Phthalate exposure and allergy in the U.S. population: results from NHANES 2005-2006

BACKGROUND

Environmental exposures to phthalates, particularly high-molecular-weight (HMW) phthalates, are suspected to contribute to allergy.

OBJECTIVE

We assessed whether phthalate metabolites are associated with allergic symptoms and sensitization in a large nationally representative sample.

METHODS

We used data on urinary phthalate metabolites and allergic symptoms (hay fever, rhinitis, allergy, wheeze, asthma) and sensitization from participants ≥ 6 years of age in the National Health and Nutrition Examination Survey (NHANES) 2005-2006. Allergen sensitization was defined as a positive response to at least one of 19 specific IgE antigens (≥ 0.35 kU/L). Odds ratios (ORs) per one log10 unit change in phthalate concentration were estimated using logistic regression adjusting for age, race, body mass index, gender, creatinine, and cotinine. Separate analyses were conducted for children (6-17 years of age) and adults.

RESULTS

The HMW phthalate metabolite monobenzyl phthalate (MBzP) was the only metabolite positively associated with current allergic symptoms in adults (wheeze, asthma, hay fever, and rhinitis). Mono-(3-carboxypropyl) phthalate and the sum of diethylhexyl phthalate metabolites (both representing HMW phthalate exposures) were positively associated with allergic sensitization in adults. Conversely, in children, HMW phthalate metabolites were inversely associated with asthma and hay fever. Of the low-molecular-weight phthalate metabolites, monoethyl phthalate was inversely associated with allergic sensitization in adults (OR = 0.79; 95% CI: 0.70, 0.90).

CONCLUSION

In this cross-sectional analysis of a nationally representative sample, HMW phthalate metabolites, particularly MBzP, were positively associated with allergic symptoms and sensitization in adults, but there was no strong evidence for associations between phthalates and allergy in children 6-17 years of age.

The obesity-asthma link in different ages and the role of body mass index in its investigation: findings from the Genesis and Healthy Growth Studies

BACKGROUND

To date, an obesity/asthma link is well defined in adults; however, the nature of such a link is obscure in children, partly due to Body Mass Index (BMI) limitations as a surrogate fat mass marker in childhood. We thus opted to investigate the association of adiposity with asthma in children of different ages, using several indices to assess fat mass.

METHODS

Wheeze ever/in the last 12 months (current) and physician-diagnosed asthma were retrospectively reported via questionnaire by the parents of 3641 children, participating in two cross-sectional studies: 1626 children aged 2-5 (the Genesis Study) and 2015 children aged 9-13 (the Healthy Growth Study). Perinatal data were recorded from the children's medical records or reported by parents. Anthropometric measurements (i.e., BMI, waist/hip circumference, biceps/triceps/subscapular/suprailiac skinfold thickness) were conducted in both cohorts; bioelectric impedance analysis (BIA) was conducted only in preadolescent children.

RESULTS

In children aged 2-5, asthma was positively correlated with conicity index, waist/hip circumference, waist-to-height ratio, skinfold thickness, and skinfold-derived percentage fat mass (P < 0.05) but not BMI or BMI-defined overweight/obesity, after adjusting for several confounders. In children aged 9-13, asthma was positively associated with conicity index, waist circumference, waist-to-height ratio, skinfold thickness, skinfold-derived percentage fat mass, BIA-derived percentage fat mass, BMI, and BMI-defined overweight/obesity, following adjustment (P < 0.05). Current/ever wheeze was not consistently associated with fat mass in either population.

CONCLUSIONS

Fat mass is positively linked to asthma in both 2-5 and 9-13 age spans. However, the failure of BMI to correlate with preschool asthma suggests its potential inefficiency in asthma studies at this age range.

Monitoring immune modulation by nutrition in the general population: identifying and substantiating effects on human health

Optimal functioning of the immune system is crucial to human health, and nutrition is one of the major exogenous factors modulating different aspects of immune function. Currently, no single marker is available to predict the effect of a dietary intervention on different aspects of immune function. To provide further guidance on the assessment and interpretation of the modulation of immune functions due to nutrition in the general population, International Life Sciences Institute Europe commissioned a group of experts from academia, government and the food industry to prepare a guidance document. A draft of this paper was refined at a workshop involving additional experts. First, the expert group defined criteria to evaluate the usefulness of immune function markers. Over seventy-five markers were scored within the context of three distinct immune system functions: defence against pathogens; avoidance or mitigation of allergy; control of low-grade (metabolic) inflammation. The most useful markers were subsequently classified depending on whether they by themselves signify clinical relevance and/or involvement of immune function. Next, five theoretical scenarios were drafted describing potential changes in the values of markers compared with a relevant reference range. Finally, all elements were combined, providing a framework to aid the design and interpretation of studies assessing the effects of nutrition on immune function. This stepwise approach offers a clear rationale for selecting markers for future trials and provides a framework for the interpretation of outcomes. A similar stepwise approach may also be useful to rationalise the selection and interpretation of markers for other physiological processes critical to the maintenance of health and well-being.

Obesity - a promoter of allergy?

The prevalence of both obesity and allergy has been increasing throughout the world, leading to the hypothesis that the two are linked to one another. This overview summarizes the results of 34 studies from 2002 to 2012 that investigated a possible contributing effect of increasing body mass on the development and prevalence of various atopic diseases. Obesity was found to clearly affect bronchial asthma. However, the correlation was stronger in the nonatopic asthma phenotype. Obesity was found to be associated with the development of atopic dermatitis in children only. No clear association was found between obesity and the prevalence of allergic rhinitis or allergic conjunctivitis or increased sensitization to food allergens. This review sums up our study results and discusses a possible role of obesity in the promotion of allergy and asthma.

Sociocultural characteristics, obesity and inflammatory biomarkers in Puerto Rican toddlers born in New York City

BACKGROUND

In the USA, Puerto Rican children have a higher prevalence of asthma than other Latino ethnicities, and acculturation is one of hypothesized reasons for this difference. We examined associations between sociocultural characteristics and serum leptin, high-sensitivity C-reactive protein (hsCRP), and body mass index (BMI), and further, among hsCRP, leptin levels, BMI percentiles, and allergic sensitization in 2-year-old children.

METHODS

IgE antibodies, leptin, and hsCRP concentrations were measured in serum from Puerto Rican toddlers (n = 143) born in New York City with a maternal history of allergy and/or asthma. Demographic and home characteristics questionnaires were administered to the mother, postpartum and two years later. Children's weight and height were measured to determine BMI percentiles.

RESULTS

More girls (60%) had leptin levels above the median compared with boys (37%) (p = 0.0063). Leptin was positively correlated with BMI (r = 0.25; p = 0.0042). Children in daycare were more likely to be obese (40% vs. 24% p < 0.06). Maternal birthplace was significantly associated with children's leptin but not with hsCRP. Leptin levels were lower for children whose mothers were born on the US mainland (GM = 2.5 ng/ml, 95% CI [2.2-2.7]) compared with those whose mothers were born in Puerto Rico or another country (GM = 3.2 ng/ml, 95% CI [2.2-3.9], t-test p = 0.01). Mothers born in another country were more likely than those born in the US mainland or Puerto Rico to have obese children (60% vs. 26% p < 0.02). Leptin, hsCRP, and BMI percentile were not associated with sensitization to any of the measured inhalant allergens or total IgE.

CONCLUSION

Even at a very young age, some acculturation factors were associated with biomarkers and anthropometric measures of obesity among this Puerto Rican pediatric population. To our knowledge, this is the first study demonstrating the association of mother's birth place with child BMI and leptin as early as 24 months.