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

Food allergy among low birthweight children in a national survey

The aim of this paper was to investigate the association between birthweight and prevalence of food allergies using a national sample of US children. Adult report of birthweight and child food allergies were obtained for years 2005-2009 from the National Health Interview Survey (NHIS), a cross-sectional household survey of the US population. A total of 51,748 children aged 0-17 years were included in the analyses representing over 73 million children. Multivariable logistic regression analyses examined associations between birthweight categories and food allergies stratified by age and gender; accounting for the complex design of NHIS. Children aged 6-12 years who were born very low birthweight (500-1,499 g) were more likely to have reported food allergy compared to referent (3,000-3,499 g), OR = 1.72; 95% CI: 1.02-2.91. However, there was no clear trend of an association between birthweight and food allergy with increasing or decreasing birthweight across all ages. Estimates were generally stronger in younger male children as compared to estimates in females of the same age group. Marginal associations for respiratory allergy (OR = 1.52; 95% CI: 1.02-2.29) and hay fever (OR = 1.54; 95% CI: 0.93-2.54) were observed among very low birthweight children aged 0-5 years. There was limited evidence for a clear association between birthweight and food allergy. Marginal associations observed in children weighing 500-1,499 g at birth support efforts to minimize preterm births and very low birthweight given the increase in pediatric food allergies and the large number of children born low birthweight each year in the US.

Food allergy: an enigmatic epidemic

Food allergy is a common disease that is rapidly increasing in prevalence for reasons that remain unknown. Current research efforts are focused on understanding the immune basis of food allergy, identifying environmental factors that may contribute to its rising prevalence, and developing immunotherapeutic approaches to establish immune tolerance to foods. Technological advances such as peptide microarray and MHC class II tetramers have begun to provide a comprehensive profile of the immune response to foods. The burgeoning field of mucosal immunology has provided intriguing clues to the role of the diet and the microbiota as risk factors in the development of food allergy. The purpose of this review is to highlight significant gaps in our knowledge that need answers to stem the progression of this disorder that is reaching epidemic proportions.

Food allergy: temporal trends and determinants

This review summarizes studies discussing temporal trends in the prevalence of food allergy as well as potential factors associated with the development of food allergy. In addition, we will address the potential hypotheses accounting for the apparent increase in food allergy prevalence. Studies suggest increased prevalence of food allergy. However, relatively little is known about its pathogenesis. This review aims to assess temporal trends in the prevalence of food allergy and discuss potential genetic, environmental, and demographic determinants. The search strategy examined the medical literature database MEDLINE (using PubMed) for the time period of January 1, 2002 to January 31, 2012. In recent decades, the prevalence of food allergy in general has increased by 0.60 % [95 % confidence interval (CI), 0.59 %-0.61 %] and the prevalence of peanut allergy by 0.027 % (95 % CI, 0.026 %-0.028 %), but it has now likely stabilized in developed countries. Genes, the environment, and demographic characteristics play a role in the pathogenesis of food allergy. Numerous environmental and demographic factors as well as gene-environment interactions may account for this increase in prevalence, but further studies are required to tease out their relative contribution.

Biomonitoring-based environmental public health indicators

This chapter discusses the use ofbiomonitoring-based indicators of exposure to environmental pollutants in environmental health information systems. Matrices for biomonitoring, organization and standardization of surveillance programs, the use of intake and body burden data, and the interpretation of surveillance data are discussed. The concept of environmental public health indicators is demonstrated using the "Persistent organic pollutants in human milk" indicator implemented in the Environment and Health Information System (ENHIS) of the WHO Regional Office for Europe. This indicator is based on the data from the WHO-coordinated surveillance of persistent organic pollutants in human milk as well as data from selected national studies. The WHO survey data demonstrate a steady decline in breast milk concentrations of dioxins across Europe. The data from biomonitoring surveys in Sweden also show a steady decline of breast milk concentrations of most persistent organic pollutants since 1970s with the exception of polybrominated diphenyl ethers (PBDEs) which increased rapidly until the late 1990s and then started to decline after the implementation of policy measures aiming at reducing exposures. The application of human biomonitoring data in support of environmental public health policy actions requires carefully designed standardized and sustainable surveillance, comprehensive interpretation of the data, and an effective communication strategy based on credible information presented in the form of indicator factsheets.

Being overweight increases susceptibility to indoor pollutants among urban children with asthma

BACKGROUND

Both being overweight and exposure to indoor pollutants, which have been associated with worse health of asthmatic patients, are common in urban minority populations. Whether being overweight is a risk factor for the effects of indoor pollutant exposure on asthma health is unknown.

OBJECTIVES

We sought to examine the effect of weight on the relationship between indoor pollutant exposure and asthma health in urban minority children.

METHODS

One hundred forty-eight children (age, 5-17 years) with persistent asthma were followed for 1 year. Asthma symptoms, health care use, lung function, pulmonary inflammation, and indoor pollutants were assessed every 3 months. Weight category was based on body mass index percentile.

RESULTS

Participants were predominantly African American (91%) and had public health insurance (85%). Four percent were underweight, 52% were normal weight, 16% were overweight, and 28% were obese. Overweight or obese participants had more symptoms associated with exposure to fine particulate matter measuring less than 2.5 μm in diameter (PM2.5) than normal-weight participants across a range of asthma symptoms. Overweight or obese participants also had more asthma symptoms associated with nitrogen dioxide (NO2) exposure than normal-weight participants, although this was not observed across all types of asthma symptoms. Weight did not affect the relationship between exposure to coarse particulate matter measuring between 2.5 and 10 μm in diameter and asthma symptoms. Relationships between indoor pollutant exposure and health care use, lung function, or pulmonary inflammation did not differ by weight.

CONCLUSION

Being overweight or obese can increase susceptibility to indoor PM2.5 and NO2 in urban children with asthma. Interventions aimed at weight loss might reduce asthma symptom responses to PM2.5 and NO2, and interventions aimed at reducing indoor pollutant levels might be particularly beneficial in overweight children.

No association between overweight and asthma or allergy in adolescence after wheezing in infancy

AIMS

The aim of the study was to evaluate the association between weight status and asthma, allergy and respiratory symptoms in adolescents with bronchiolitis in infancy.

SUBJECTS AND METHODS

At age 15-18 years, a questionnaire was sent to 96 study subjects hospitalized for wheezing at age <24 months and followed up subsequently. Sixty-seven (70%) of them answered. Weight and height data for body mass index (BMI) calculation were available in 60 (63%) cases. Asthma, allergy, respiratory symptoms and the use of asthma medication were compared between overweight or obese and normal weight groups constructed by age- and sex-specific BMI standard deviation scores (BMI-SDS). Population controls matched for sex, and birth month and place, were recruited for this study phase at age 15-18 years.

RESULTS

Eleven (18.3%) study subjects were overweight (BMI-SDS >0.78 in males and >1.16 in females) and only 3 (5.0%) were obese (BMI-SDS >1.70 in males and >2.10 in females) at 16.5 (median) years of age. Overweight or obesity had no significant association with doctor-diagnosed or self-reported asthma, allergy or the use of inhaled corticosteroids. The negative results were confirmed by adjusted analyses.

CONCLUSION

Weight status had no association with asthma or allergy in adolescence after wheezing in infancy.

Obesity lowers the threshold of allergic sensitization and augments airway eosinophilia in a mouse model of asthma

BACKGROUND

Clinical and epidemiological studies show a close association between obesity and the risk of asthma development. The underlying cause-effect relationship between metabolism, innate and adaptive immunity, and inflammation remains to be elucidated.

METHODS

We developed an animal model to study the interaction between metabolic abnormalities and experimentally induced asthma. Obesity-susceptible AKR mice were fed with high-fat diet (HFD) or normal low-fat diet (LFD) and subjected to a protocol of ovalbumin (OVA) sensitization and airway allergen challenges followed by assessment of inflammation and lung function.

RESULTS

AKR mice developed obesity and a prestage of metabolic syndrome following HFD. This phenotype was associated with an increase in proinflammatory macrophages (CD11b+/CD11c+) together with higher serum levels of interleukin 6. Obese mice showed increased susceptibility to allergic sensitization as compared to LFD animals. Anti-ovalbumin IgE antibody titers correlated positively and anti-OVA IgG2a antibodies titers correlated negatively with body weight. Airway eosinophilia showed a positive correlation with body weight, whereas mucus production did not change with obesity.

CONCLUSIONS

This obesity model demonstrates that HFD-induced obesity lowers the sensitization threshold in a model of asthma. This finding helps to understand why, particularly during childhood, obesity is a risk factor for the development of allergic asthma.

Association between obesity and asthma in Japanese preschool children

Obesity may increase the risk of subsequent asthma. We have previously reported that there is a clear association between obesity and asthma in Japanese school-aged children. To evaluate whether a similar association exists in younger children, a nationwide cross-sectional questionnaire-based survey was performed focusing on children aged 4-5 yr. A child who had experienced wheezing during the past 12 months and had ever been diagnosed with asthma by a physician was defined as having current asthma. Overweight and underweight were defined as BMI ≥90th percentile and ≤10th percentile, respectively, according to the reference values for Japanese children from 1978 to 1981. After excluding 2547 children because of incomplete data, 34,699 children were analyzed. Current asthma was significantly more prevalent in overweight children compared with underweight and normal weight children (13.2% for overweight vs. 10.5% for underweight and 11.1% for normal weight; both p < 0.001). Even after adjusting for other variables, such as gender, other coexisting allergic diseases, and parental history of asthma, there was an association between overweight and current asthma (adjusted odds ratio: 1.23, 95% CI: 1.10-1.38, p < 0.001). Even in preschool children, obesity is already associated with asthma, and there was no gender effect on this association. Physicians should consider the impact of obesity when managing asthma in younger children.

Effect of urbanisation on the relationship between total serum IgE and asthma

It is unclear if the relationship of total serum IgE with asthma varies with degree of urbanisation. We hypothesised that the relationship of total serum IgE to asthma is more pronounced in an urban versus a rural environment. We enrolled 1441 children aged 13-15 years in a peri-urban shanty town in Lima, Peru (n=725) and 23 villages in rural Tumbes, Peru (n=716). We asked participants about asthma and allergy symptoms, environmental exposures and sociodemographics; and performed spirometry, and exhaled nitric oxide and allergy skin testing. We obtained blood for total serum IgE in 1143 (79%) participants. Geometric means for total serum IgE were higher in Lima versus Tumbes (262 versus 192 kU·L(-1); p<0.001). The odds of asthma increased by factors of 1.6 (95% CI 1.3-2.0) versus 1.4 (95% CI 0.9-2.1) per log unit increase in total serum IgE in Lima versus Tumbes, respectively. Atopy was an effect modifier of the relationship of total serum IgE on asthma. Among atopics and non-atopics, the odds of asthma increased by a factor of 2.0 (95% CI 1.5-2.7) and 1.0 (95% CI 0.7-1.4) per log unit increase in total serum IgE, respectively. Total serum IgE was associated with atopic asthma but not with non-atopic asthma. Urbanisation did not appear to be an effect modifier of this relationship.

Early life precursors, epigenetics, and the development of food allergy

Food allergy (FA), a major clinical and public health concern worldwide, is caused by a complex interplay of environmental exposures, genetic variants, gene-environment interactions, and epigenetic alterations. This review summarizes recent advances surrounding these key factors, with a particular focus on the potential role of epigenetics in the development of FA. Epidemiologic studies have reported a number of nongenetic factors that may influence the risk of FA, such as timing of food introduction and feeding pattern, diet/nutrition, exposure to environmental tobacco smoking, prematurity and low birth weight, microbial exposure, and race/ethnicity. Current studies on the genetics of FA are mainly conducted using candidate gene approaches, which have linked more than 10 genes to the genetic susceptibility of FA. Studies on gene-environment interactions of FA are very limited. Epigenetic alteration has been proposed as one of the mechanisms to mediate the influence of early life environmental exposures and gene-environment interactions on the development of diseases later in life. The role of epigenetics in the regulation of the immune system and the epigenetic effects of some FA-associated environmental exposures are discussed in this review. There is a particular lack of large-scale prospective birth cohort studies that simultaneously assess the interrelationships of early life exposures, genetic susceptibility, epigenomic alterations, and the development of FA. The identification of these key factors and their independent and joint contributions to FA will allow us to gain important insight into the biological mechanisms by which environmental exposures and genetic susceptibility affect the risk of FA and will provide essential information to develop more effective new paradigms in the diagnosis, prevention, and management of FA.

High glucose increases the expression of proinflammatory cytokines and secretion of TNFα and β-hexosaminidase in human mast cells

Epidemiological studies demonstrated that obesity, which is a high-risk factor for development of hyperglycemia-associated metabolic syndromes, is associated with prevalence/incidence of allergic diseases. To elucidate the underlying mechanisms of the relationship between hyperglycemia and allergy, we examined the effect of high glucose on the activation of human mast cell lines, HMC-1 and LAD2. HMC-1 and LAD2 cells were cultured in low (5.5 mM) and high (25 mM)-glucose Dulbecco's modified Eagle's medium (DMEM). High-glucose medium increased the intracellular reactive oxygen species levels in HMC-1 and LAD2 cells after 2 days of incubation; in HMC-1 cells, the expression levels of tumor necrosis factor (TNF) α, interleukin (IL)-1β, IL-6, and IL-13 were increased significantly. The β-hexosaminidase release rates were not significantly different between LAD2 cells cultured in both media; however, the intracellular and extracellular activities of β-hexosaminidase in cells were significantly higher in high-glucose than in low-glucose media. High glucose increased the secretion of TNFα by unstimulated HMC-1 cells and IgE crosslinking-stimulated LAD2 cells. High glucose increased the phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinases (MAPKs), which regulate the expression of TNFα and other inflammatory cytokines, in both HMC-1 and LAD2 cells. Thus, high glucose increased the expression of proinflammatory and proallergic cytokines, the secretion of TNFα, and β-hexosaminidase activity in human mast cells. Our result suggests that hyperglycemia promotes the activation of human mast cells associated with allergy and inflammation under unstimulated and stimulated conditions.

Association between atopic dermatitis and obesity in adulthood

BACKGROUND

Obesity in early childhood is associated with increased risk for and severity of atopic dermatitis (AD). Objective To determine whether obesity in adulthood is associated with risk of AD.

METHODS

This was a retrospective case-control study of 2090 adults using questionnaire, height and weight, and skin-prick testing between January 1994 and December 2003.

RESULTS

Obesity in adults was associated with increased AD [multinomial logistic regression: adjusted odds ratio (aOR) 1·43, 95% confidence interval (CI) 1·08-1·89; P=0·01], but not nonatopic dermatitis (aOR 0·59, 95% CI 0·21-1·68; P=0·32). Obesity was also associated with increased atopic asthma (aOR 1·98, 95% CI 1·47-2·66, P<0·0001), but not associated with nonatopic asthma (P=0·20), atopic or nonatopic rhinoconjunctivitis (P=0·08 and 0·31, respectively), food allergies (P=0·67 and 0·35, respectively) or atopy (P=0·40). The association between obesity and AD remained significant even when controlling for history of asthma, rhinoconjunctivitis and food allergies (aOR 1·40, 95% CI 1·05-1·86; P=0·02) or in subset analyses of subjects with AD alone (aOR 1·96, 95% CI 1·02-3·75; P=0·04) and with comorbid asthma, rhinoconjunctivitis and/or food allergies (aOR 1·40, 95% CI 1·03-1·91; P=0·03).

CONCLUSION

Obesity in adulthood is associated with AD. Further studies are warranted to determine if weight loss may prevent or mitigate AD in adults.

Early childhood overweight and asthma and allergic sensitization at 8 years of age

OBJECTIVES

Our aim was to examine the associations between high BMI and changes in BMI status during the first 7 years of life and asthma and allergic sensitization at age 8 years.

METHODS

A birth cohort of newborn infants was followed for 8 years. Repeated parental questionnaires provided information on environmental exposures and health outcomes. Information on height and weight during childhood was retrieved from preschool and school health care records. The analyses included the 2075 children for whom information was available on weight and height, as well as on asthma, at age 8 years.

RESULTS

A high BMI (≥85th percentile) at age 1, 4, and/or 7 years was associated with an increased risk of asthma at age 8 years. However, no significant association was observed among children with high BMI at age 12 and/or 18 months (early age) or at age 4 years who developed a normal BMI by age 7 years. The risk was increased among children with high BMI at age 7 years, regardless of their earlier weight. Moreover, we observed an increased risk of sensitization to inhalant allergens among children with high BMI at age 7 years.

CONCLUSIONS

Our study indicates that high BMI during the first 4 years does not increase the risk of asthma at school age among children who have developed a normal weight by age 7 years. However, high BMI at age 7 years is associated with an increased risk of asthma and sensitization to inhalant allergens.

Obesity is associated with increased asthma severity and exacerbations, and increased serum immunoglobulin E in inner-city adults

BACKGROUND

Obesity is associated with increased asthma and atopy.

OBJECTIVE

To determine whether or not obesity in inner-city adults is associated with increased asthma prevalence, severity and exacerbations and IgE responses.

METHODS

This retrospective study involved 246 adults with asthma and other atopic disorders who were seen at an asthma clinic in New York City between 1997 and 2010. Height, weight, asthma diagnosis and symptoms, peak flow (PF), spirometry, serum IgE levels and white blood cell differentials were recorded.

RESULTS

Asthmatic patients had higher body mass index than non-asthmatics (median, interquartile range: 30.5, 10.2 vs. 27.8, 8.8; Mann-Whitney U-test, P = 0.0006). Class I and II/III obesity were associated with increased asthma (I: OR: 2.35, 95% CI: 1.04-5.34, P = 0.04; II/III: OR: 3.25, 95% CI: 1.36-7.74, P = 0.008). Class I and II/III obesity were associated with worsened asthma severity (ordinal logistic regression; I: OR: 4.23, 95% CI: 1.61-11.06, P = 0.003; II/III: OR: 2.76, 95% CI: 1.08-7.09, P = 0.03). Class II/III obesity was associated with increased asthma exacerbations requiring oral corticosteroids (repeated measures logistic regression, OR: 1.13, 95% CI: 1.03-1.25; P = 0.01) and increased requirement of inhaled corticosteroid for long-term asthma management (OR: 1.45, 95% CI: 1.29-1.62; P < 0.0001). In asthmatics, class II/III obesity was associated with decreased PF (general linear model, least squares mean ± SEM: 333.8 ± 37.4 vs. 396.2 ± 32.1 L/min; P = 0.007), forced expiratory volume in 1 s (75.2 ± 4.6 vs. 88.4 ± 5.6%; P = 0.03) and forced vital capacity (83.2 ± 4.7 vs. 109.2 ± 6.0%; P = 0.0002) and increased serum IgE (480.2 ± 88.3 vs. 269.0 ± 66.6 IU/mL; P = 0.04) and neutrophils (66.6 ± 3.7 vs. 60.1 ± 3.8%; P = 0.02). Class I obesity was also associated with increased serum IgE (458.7 ± 68.9, P = 0.03).

CONCLUSION AND CLINICAL RELEVANCE

Obesity in inner-city adults may be both a risk and exacerbating factor for atopic asthma.

Effect of prenatal indoor pet exposure on the trajectory of total IgE levels in early childhood

BACKGROUND

The presence of pets in a home during the prenatal period and during early infancy has been associated with a lower prevalence of allergic sensitization and total IgE levels in middle childhood. No studies have examined the effect of pet exposure in a population-based cohort by using multiple early-life measures of serum total IgE.

OBJECTIVE

We sought to examine within-individual longitudinal trends in total IgE levels during early childhood and assess the effect of indoor prenatal pet exposure on those trends. Also, we sought to use a statistical method that was flexible enough to allow and account for unequally spaced study contacts and missing data.

METHODS

Using the population-based Wayne County Health, Environment, Allergy and Asthma Longitudinal Study birth cohort (62% African American), we analyzed 1187 infants with 1 to 4 measurements of total IgE collected from birth to 2 years of age. Effects of pet exposure on the shape and trajectory of IgE levels were assessed by using a multilevel longitudinal model, accommodating repeated measures, missing data, and the precise time points of data collection.

RESULTS

The best-fit shape to the trajectory of IgE levels was nonlinear, with an accelerated increase before 6 months. Total IgE levels were lower across the entire early-life period when there was prenatal indoor pet exposure (P < .001). This effect was statistically significantly stronger in children delivered by means of cesarean section versus those delivered vaginally (P < .001 and P < .06, respectively) and in those born to non-African American (P < .001) versus African American (P < .3) mothers.

CONCLUSION

Pet exposure and delivery mode might be markers of infant exposure to distinct microbiomes. The effect of exposures might vary by race, suggesting a differential effect by ancestry.

The in vitro effects of advanced glycation end products on basophil functions

BACKGROUND

Basophils are thought to play pivotal roles in the pathogenesis of allergic reactions, but their roles in inflammation associated with systemic abnormalities such as metabolic disorders remain largely unknown. Advanced glycation end products (AGEs) are potentially important substances produced in high-glucose disease conditions. In this in vitro study, we investigated whether the biological functions of human basophils can be influenced by AGEs.

METHODS

We analyzed the effects of AGEs on various functions and markers of human basophils, including CD11b expression, apoptosis, degranulation, and cytokine production.

RESULTS

Flow cytometric analysis indicated that the level of the receptor for AGEs (RAGE) on the surface of freshly isolated basophils was very low but was clearly upregulated by IL-3. Apoptosis of basophils was induced by high concentrations of glycated albumin. Although glycated albumin failed to affect the level of surface CD11b expression or to trigger degranulation or production of IL-4 and IL-13 in basophils, it dose-dependently induced IL-6 and IL-8 secretion.

CONCLUSIONS

AGEs seem to act on human basophils; they suppress the cells' longevity but elicit secretion of inflammatory cytokines. Through these biological changes, basophils might play some roles in inflammatory conditions associated with metabolic disorders presenting elevated levels of AGEs.

Changes in adiposity status from childhood to adolescence: a 6-year longitudinal study in Portuguese boys and girls

BACKGROUND

Cross-sectional data show high prevalence of overweight in Portuguese children, but there are few longitudinal studies describing the patterns of obesity development in the young.

AIM

To examine the trajectories of obesity from late childhood to adolescence.

SUBJECTS AND METHODS

Triceps and subscapular skinfold thickness measurements were carried out in 288 children at age 9 (baseline) and later at age 15 (follow-up). Percentage body fat (%BF) was estimated according to Slaughter equations and the health-related definition of obesity ( ≥ 25%BF in boys and ≥ 30%BF in girls) was used.

RESULTS

In boys, the prevalence of obesity decreased from 21.9% to 14.8% (p < 0.05) while in girls it increased from 14.3% to 19.5%. The incidence of obesity in the 6-year study period was 2.6% and 8.3% for boys and girls, respectively (p < 0.05). In comparison with girls, the percentage of boys that reversed obesity was more than 3-fold higher (3% vs 9.7%, p < 0.05). Obesity tracked moderately in both sexes (Kappa = 0.6, p < 0.001).

CONCLUSION

The results indicate a marked sex difference in the incidence and reversal of obesity from late childhood to adolescence that is unfavourable to girls. Consideration of this difference might be important when designing programmes for the prevention and treatment of obesity focusing on this period.

Can food allergy be prevented? The current evidence

Food allergy is a recognized public health concern, for which preventative strategies are required. Although an intervention that adequately protects against the development of food allergy has still to be identified, limited benefits have been shown for the prevention of related allergic conditions such as eczema, and to a lesser extent asthma and rhinitis; these benefits are usually limited to at-risk populations. Prevention strategies need to be tested using randomized controlled study designs that account for the numerous methodological challenges, safety concerns, and necessary ethical limitations.

Association between obesity and atopic dermatitis in childhood: a case-control study

BACKGROUND

Obesity in children is associated with increased asthma and atopy.

OBJECTIVE

We sought to determine whether obesity in childhood or adolescence increases the risk of atopic dermatitis.

METHODS

This retrospective, practice-based, case-control study randomly sampled 414 children and adolescents (age, 1-21 years) with atopic dermatitis between January 2000 and December 2007 and 828 randomly sampled healthy control subjects. Information was obtained from an electronic medical record. Observations were made before the a priori hypothesis.

RESULTS

Obesity in children is associated with increased atopic dermatitis (conditional logistic regression: odds ratio, 2.00; 95% CI, 1.22-3.26; P = .006). These atopic dermatitis-predisposing effects are found when obesity started by less than 2 years of age (adjusted odds ratio [aOR], 15.10; 95% CI, 1.51-151.21; P = .02) and 2 to 5 years (aOR, 2.58; 95% CI, 1.24-5.41; P = .01) but not greater than 5 years (aOR, 1.32; 95% CI, 0.66-2.64; P = .43) and when obesity was prolonged for 2.5 to 5 years (aOR, 2.64; 95% CI, 1.13-6.18; P = .03) and greater than 5 years (aOR, 3.40; 95% CI, 1.34-8.63; P = 0.01). Obesity is associated with more severe atopic dermatitis (ordinal logistic regression: aOR, 2.37; 95% CI, 1.24-5.37; P = .01). Obese children who eventually have atopic dermatitis require more frequent pediatrician visits for the management of atopic dermatitis (ordinal logistic regression: aOR, 2.22; 95% CI, 1.12-4.50; P = .03).

CONCLUSION

Prolonged obesity in early childhood is a risk factor for atopic dermatitis. Weight loss might be an important approach for the prevention and treatment of atopic dermatitis in children.

Ensuring children eat a healthy diet: a theory-driven focus group study to inform communication aimed at parents

The Theory of Planned Behavior (TPB) served as a framework for analyzing focus group transcripts (N = 43) focused on parents' perceptions of the challenges of ensuring their children eat a healthy diet. The results suggest that parents consider their beliefs and behaviors as individuals within a society, within families, within cultures, as inheritors of family traditions, and as parents who influence or fail to influence the attitudes and behaviors of their children. The results showed the particular salience of factors related to the TPB concepts of perceived norms and control. Approaches to building theory-driven nursing interventions are suggested.

Epidemiology of food allergy

Adverse reactions to foods can occur for a variety of reasons, but a food allergy is caused by a specific immune response. Challenges to determine the prevalence of food allergy include misclassification, biased participation, lack of simple diagnostic tests, rapid evolution of disease, large numbers of potential triggers, and varied clinical phenotypes. Nonetheless, it is clear that this is a common disorder, with studies suggesting a cumulative prevalence of 3% to 6%, representing a significant impact on quality of life and costs. The inclusion of mild reactions to fruits and vegetables could result in calculation of prevalence exceeding 10% in some regions. There are data from numerous studies to suggest an increase in prevalence, but methodologic concerns warrant caution. Prevalence varies by age, geographic location, and possibly race/ethnicity. Many childhood food allergies resolve. Population-based epidemiologic studies have generated numerous novel theories regarding risks, including modifiable factors such as components of the maternal and infant diet, obesity, and the timing of food introduction. Recent and ongoing studies provide insights on risk factors, prevalence, and natural course that may inform clinical trials to improve diagnosis, prevention, and treatment.

Association of prescription H1 antihistamine use with obesity: results from the National Health and Nutrition Examination Survey

The incidence of obesity in the United States has reached epidemic proportions. Previous research has shown several medications exert noticeable effects on body-weight regulation. Histamine-1 (H1) receptor blockers commonly used to alleviate allergy symptoms are known to report weight gain as a possible side effect. Therefore, we investigated the association between prescription H1 antihistamine use and obesity in adults using data from the 2005-2006 National Health and Nutrition Examination Survey (NHANES). Adults taking prescription H1 antihistamines were matched by age and gender with controls and compared on the basis of body measurements, plasma glucose, insulin concentrations, and lipid levels. Prescription H1 antihistamine users had a significantly higher weight, waist circumference, and insulin concentration than matched controls. The odds ratio (OR) for being overweight was increased in prescription H1 antihistamine users. H1 antihistamine use may contribute to the increased prevalence of obesity and the metabolic syndrome in adults given these medications are also commonly used as over-the-counter remedies.

The effect of past food avoidance due to allergic symptoms on the growth of children at school age

BACKGROUND

The influence of food avoidance due to allergic symptoms in infancy on the growth of children at school age has not been well evaluated.

METHODS

To determine the growth of schoolchildren who avoided eggs, milk, or wheat due to immediate allergic symptoms in infancy (food avoiders in infancy) (FAI), a questionnaire on the presence of allergic diseases, as well as present height and weight, was administered to the parents of 14,669 schoolchildren. 11,473 subjects had available data. The height and weight standard deviation scores (HtSDS and WtSDS) and body mass index percentile (BMI percentile) of each subject were calculated.

RESULTS

FAI had significantly lower WtSDS than non-FAI (P = 0.01). Among those with avoidance at age 3 years, those who avoided two or more foods and those who avoided milk had significantly lower HtSDS than their counterparts (P = 0.02 and 0.04, respectively). FAI had a significantly lower prevalence of obesity (P = 0.01) and overweight (P = 0.002), while there was no difference in the prevalence of underweight (P = 0.58), resulting in a significantly higher prevalence of appropriate weight (P = 0.01) compared to non-FAI. Significantly lower prevalence of obesity and overweight was observed even among those who terminated the avoidance by age 3 years.

CONCLUSIONS

FAI were less likely to be obese or overweight, resulting in a higher prevalence of appropriate weight at school age. Further investigation should contribute to better management of food allergy and obesity.

Association of childhood obesity with atopic and nonatopic asthma: results from the National Health and Nutrition Examination Survey 1999-2006

BACKGROUND

Obesity and asthma prevalence have both risen among children over the last several decades, and research efforts increasingly suggest that obesity is associated with asthma. Some, but not all, studies have shown that the effect of obesity on asthma is stronger among nonatopic individuals than among those with atopy. Systemic inflammation may be a factor in this relationship.

OBJECTIVE

To examine the association of obesity with atopic and nonatopic asthma among U.S. children and to assess the role of C-reactive protein.

DESIGN

Nationally representative data from the National Health and Nutrition Examination Survey (NHANES) were used to examine the relationship of weight to current asthma using logistic regression. Overweight was defined as ≥ 85th percentile of body mass index (BMI)-for-age and obesity was defined as ≥ 95th percentile of BMI-for-age. The presence of at least one positive allergen-specific immunoglobulin E (IgE) was used to stratify the relationship by atopic status in 2005-2006 data (n = 3387). Setting and Participants. Stratified, multistage probability sampling was used to identify survey participants. This analysis includes children ages 2-19 (n = 16,074) from the 1999-2006 NHANES who have information on BMI and current asthma.

MAIN OUTCOME MEASURE

Self-report of doctor-diagnosed current asthma.

RESULTS

Obesity was significantly related to current asthma among children and adolescents (odds ratio [OR]: 1.68, 95% confidence interval [CI]: 1.33, 2.12). The association was stronger in nonatopic children (OR: 2.46, 95% CI: 1.21, 5.02) than in atopic children (OR: 1.34, 95% CI: 0.70, 2.57) (interaction p value = .09). C-reactive protein levels were associated with current asthma in nonatopic children, but not after adjusting for BMI.

CONCLUSION

Excess weight in children is associated with higher rates of asthma, especially asthma that is not accompanied by allergic disease.

Clinical aspects of pediatric food allergy and failed oral immune tolerance

Food allergy seems to represent a new spectrum of disease that has elicited significant community concern and extended waiting lists for allergists and gastroenterologists alike. The apparent rise in prevalence of IgE-mediated food allergy (and associated risk of anaphylaxis) has been postulated to result from effects of a "modern lifestyle" but as yet clear environmental risk factors have not yet emerged. Family history seems to contribute to risk suggesting that gene-environment interactions will be important for identifying a subpopulation with increased susceptibility to any identified lifestyle effects. Non-IgE-mediated food allergy (including food-induced enteropathies and colitides, eosinophilic esophagitis, and Crohn's disease) with potentially similar environmental triggers resulting in diverse immune dysregulatory mechanisms. The evidence underpinning the putative rise in food allergy is discussed and potential mechanisms of disease explored. Clinical aspects of various food allergic conditions including non-IgE-mediated food allergy are outlined.

Relationship of serum cholesterol levels to atopy in the US population

BACKGROUND

Cholesterol promotes Th2 immunity and allergic inflammation in rodents; whether this occurs in humans is unclear. Reports of both direct and inverse associations between serum cholesterol and atopy in different populations suggest that race and/or other demographic variables may modify these relationships.

AIMS OF THE STUDY

To determine the relationships between levels of three serum cholesterol measures [total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), and non-HDL-C] and atopy in a sample representative of the US population.

METHODS

Cross-sectional study of 6854 participants aged > or =6 years from the 2005-2006 National Health and Nutrition Examination Survey.

RESULTS

In the overall population, adjusted odds ratios (AORs) per two-standard deviation increase in TC and non-HDL-C for biochemical atopy (defined as > or =1 allergen-specific IgE to 19 allergens) were 1.17 [95% confidence interval (CI), 1.00-1.38] and 1.19 (95% CI, 1.03-1.39), respectively. Interactions by race were noted for the two relationships (interaction P = 0.004 and P = 0.009, respectively) with non-Hispanic Whites (NHWs) having direct relationships [TC: AOR 1.27 (95% CI, 1.03-1.57); non-HDL-C: AOR 1.27 (95% CI, 1.03-1.56)] and non-Hispanic Blacks (NHBs) inverse relationships [TC: AOR 0.77 (95% CI, 0.62-0.95); non-HDL-C: AOR 0.86 (95% CI, 0.69-1.08)]. The adjusted HDL-C-atopy relationship was nonsignificant for NHWs and inverse for NHBs [AOR 0.77 (95% CI, 0.61-0.96)]. Relationships were independent of body mass index and serum C-reactive protein and unmodified by corticosteroid or statin usage. Results were similar using current hay fever/allergy as the atopy outcome.

CONCLUSIONS

There are marked inter-racial differences in the relationship between serum cholesterol and atopy in the US population.

Using nature and outdoor activity to improve children's health

Childhood obesity affects 17% or 12.5 million of America's children, contributing to the rise in children's health disparities. Type 2 diabetes, asthma, vitamin D deficiency, and attention-deficit/hyperactivity disorder have also increased over the past few decades. A shift toward a sedentary lifestyle is a major contributor to the decline in children's health. Children spend more time indoors using electronic media and less time engaged in outdoor unstructured play. This article reviews the current evidence of the mental and physical health benefits associated with unstructured, outdoor activities and time spent in a natural environment such as a park or other recreational area. Pediatric health care providers should recommend outdoor activities for children and refer families to safe and easily accessible outdoor areas. Pediatric health care providers can incorporate this simple, lifestyle-based intervention into anticipatory guidance.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2009

This review highlights some of the research advances in anaphylaxis and hypersensitivity reactions to foods, drugs, and insects, as well as advances in allergic skin disease that were reported in the Journal in 2009. Among key epidemiologic observations, several westernized countries report that more than 1% of children have peanut allergy, and there is some evidence that environmental exposure to peanut is a risk factor. The role of regulatory T cells, complement, platelet-activating factor, and effector cells in the development and expression of food allergy were explored in several murine models and human studies. Delayed anaphylaxis to mammalian meats appears to be related to IgE binding to the carbohydrate moiety galactose-alpha-1,3-galactose, which also has implications for hypersensitivity to murine mAb therapeutics containing this oligosaccharide. Oral immunotherapy studies continue to show promise for the treatment of food allergy, but determining whether the treatment causes tolerance (cure) or temporary desensitization remains to be explored. Increased baseline serum tryptase levels might inform the risk of venom anaphylaxis and might indicate a risk for mast cell disorders in persons who have experienced such episodes. Reduced structural and immune barrier function contribute to local and systemic allergen sensitization in patients with atopic dermatitis, as well as increased propensity of skin infections in these patients. The use of increased doses of nonsedating antihistamines and potential usefulness of omalizumab for chronic urticaria was highlighted. These exciting advances reported in the Journal can improve patient care today and provide insights on how we can improve the diagnosis and treatment of these allergic diseases in the future.

Obesity and respiratory diseases in childhood

The prevalence of childhood obesity has more than tripled over the past five decades. Obesity results in low lung volumes, likely through increased loading of the chest wall and abdomen. The prevalence of asthma in children has paralleled the rise in obesity; obesity may increase the severity of asthma, but a direct link has been difficult to establish. Obesity is a risk factor for obstructive sleep apnea (OSA) in children as well as adults. Obese children may be at increased risk for persistent OSA following adenotonsillectomy treatment for OSA. Severe obesity and OSA may lead to the obesity-hypoventilation syndrome, with hypoxia, hypercapnia, and reduced ventilatory drive. Obesity can increase a child's risk for complications of anesthesia and recovery from surgery.