Search

Objective: Exposure to indoor pollutants and allergens has been speculated to cause asthma symptoms and exacerbations and influence the risk of developing asthma. The aim of this article is to review the medical literature regarding the role of the indoor environment on inner-city childhood asthma., Data Sources: A literature search was performed in PubMed. Studies focusing on inner-city indoor allergen, childhood asthma, and environmental controls were included., Results: The prevalence of asthma in children is increasing especially in inner-city area. Exposure to high levels of indoor allergens and pollutants has been related to asthma development. Studies have shown that mouse, cockroach, pets, dust mite, mold, tobacco smoke, endotoxin and nitrogen dioxide are the important exposures. Recent studies have shown that indoor environmental control is beneficial in reducing asthma morbidity and development., Conclusions: Inner-city children are exposed to various indoor allergens and pollutants that may lead to asthma development and exacerbation of existing asthma. Multifaceted environmental controls are beneficial in improving asthma symptom and maybe a viable prevention strategy. Further prospective studies of environmental intervention are needed to further identify effective strategies to improve and prevent asthma symptoms in inner-city children.

Asthma is the most common chronic illness of childhood and inner city residents suffer a disproportionately high rate of asthma diagnosis and asthma morbidity. The School Inner City Asthma Study investigates the school classroom based environmental exposures that may lead to asthma morbidity in inner city school children with asthma. Within this cohort, we investigated the role of methylation at the promoter region of the beta-2-adrenergic receptor in relation to asthma morbidity. We found that high levels of methylation in the region studied was significantly associated with decreased report of dyspnea and trended towards significance for lower levels of asthma symptoms and airway obstruction. This Research Highlight discusses the findings of the recent study and the investigators' active research endeavors.

Background: Genetic variation in the β-2 adrenergic receptor gene (ADRB2) has been implicated in asthma severity and control with conflicting results. Epigenetic variation in the ADRB2 may play an important role in asthma phenotype., Objective: We aimed to evaluate whether DNA methylation of ADRB2 is associated with asthma phenotypes in inner-city school-aged children., Methods: Multiple CpG sites in the promoter region of ADRB2 gene were analysed in 177 children enrolled in the School Inner-City Asthma Study. Blood- or saliva-derived DNA was measured by bisulphite-polymerase chain reaction pyrosequencing assay. Average percentage DNA methylation across the sites was evaluated for association with asthma severity (report of dyspnoea, night-time symptoms, rescue medication use, and baseline spirometry) and morbidity (school absences and unscheduled healthcare visits). Three clades composed of highly correlated methylation sites within the methylated segment of ADRB2 were further analysed., Results: Methylation of individual sites generally ranged from 0% to 6% with average percentage methylation across sites of 2.4%. Univariate analyses strongly favoured the association of higher percentage methylation with lower asthma severity measured by report of dyspnoea. Furthermore, there was a non-significant trend towards less rescue medication use, night-time symptoms, school absences, activity limitation due to asthma, and improved lung function measurements with increased methylation. Multivariate analysis demonstrated methylation of ADRB2 gene significantly associated with less dyspnoea (odds ratio (OR) 0.2, 95% confidence interval (CI), 0.1-0.6, P = 0.002). Each of the three clades of methylation sites showed a strong, but not statistically significant, effect on decreased dyspnoea., Conclusions and Clinical Relevance: DNA methylation in the ADRB2 gene is associated with decreased asthma symptom severity, suggesting a role for methylation in asthma phenotypes., (© 2013 John Wiley & Sons Ltd.)

Background: Children with asthma have increased prevalence of food allergies. The relationship between food allergy and asthma morbidity is unclear., Objective: We aimed to investigate the presence of food allergy as an independent risk factor for increased asthma morbidity by using the School Inner-City Asthma Study, a prospective study that evaluates risk factors and asthma morbidity among urban children., Methods: We prospectively surveyed, from inner-city schools, 300 children with physician-diagnosed asthma, followed by clinical evaluation. Food allergies were reported, which included symptoms experienced within 1 hour of food ingestion. Asthma morbidity, pulmonary function, and resource utilization were compared between children with food allergies and those without., Results: Seventy-three of 300 children with asthma (24%) surveyed had physician-diagnosed food allergy, and 36 (12%) had multiple food allergies. Those with any food allergy independently had increased risk of hospitalization (OR [odds ratio] 2.35 [95% CI, 1.30-4.24]; P = .005) and use of controller medication (OR 1.99 [95% CI, 1.06-3.74]; P = .03). Those with multiple food allergies also had an independently higher risk of hospitalization in the past year (OR 4.10 [95% CI, 1.47-11.45]; P = .007), asthma-related hospitalization (OR 3.52 [95% CI, 1.12-11.03]; P = .03), controller medication use (OR 2.38 [95% CI, 1.00-5.66]; P = .05), and more provider visits (median, 4.5 vs 3.0; P = .008). Furthermore, lung function was significantly lower (percent predicted FEV1 and FEV1/FVC ratios) in both food allergy category groups., Conclusions: Food allergy is highly prevalent in inner-city school-aged children with asthma. Children with food allergies have increased asthma morbidity and health resource utilization with decreased lung function, and this association is stronger in those with multiple food allergies., (Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Objectives: The forced expiratory volume in 1 second (FEV(1)) felt to be an objective measure of airway obstruction is often normal in asthmatic children. The forced expiratory flow between 25% and 75% of vital capacity (FEF(25-75)) reflects small airway patency and has been found to be reduced in children with asthma. The aim of this study was to determine whether FEF(25-75) is associated with increased childhood asthma severity and morbidity in the setting of a normal FEV(1), and to determine whether bronchodilator responsiveness (BDR) as defined by FEF(25-75) identifies more childhood asthmatics than does BDR defined by FEV(1)., Methods: The Boston Children's Hospital Pulmonary Function Test database was queried and the most recent spirometry result was retrieved for 744 children diagnosed with asthma between 10 and 18 years of age between October 2000 and October 2010. Electronic medical records in the 1 year prior and the 1 year following the date of spirometry were examined for asthma severity (mild, moderate, or severe) and morbidity outcomes for the three age, race, and gender-matched subgroups: Group A (n = 35) had a normal FEV(1), FEV(1)/forced vital capacity (FVC), and FEF(25-75); Group B (n = 36) had solely a diminished FEV(1)/FVC; and Group C (n = 37) had a normal FEV(1), low FEV(1)/FVC, and low FEF(25-75). Morbidity outcomes analyzed included the presence of hospitalization, emergency department visit, intensive care unit admission, asthma exacerbation, and systemic steroid use., Results: Subjects with a low FEF(25-75) (Group C) had nearly 3 times the odds ratio (OR) (OR = 2.8, p < .01) of systemic corticosteroid use and 6 times the OR of asthma exacerbations (OR = 6.3, p > .01) compared with those who had normal spirometry (Group A). Using FEF(25-75) to define BDR identified 53% more subjects with asthma than did using a definition based on FEV(1)., Conclusions: A low FEF(25-75) in the setting of a normal FEV(1) is associated with increased asthma severity, systemic steroid use, and asthma exacerbations in children. In addition, using the percent change in FEF(25-75) from baseline may be helpful in identifying BDR in asthmatic children with a normal FEV(1).

Atopic dermatitis (AD) in young children is often followed by the development of asthma (atopic march). The role of environmental exposures is unclear in this high-risk population. We aimed to determine the predictive relationship between indoor allergen exposures, particularly pets, rodents, and cockroaches, to the development of asthma in a prospective pediatric cohort. Children with AD and a family history of allergy were followed prospectively with questionnaire ascertainment of environmental exposure to cats, dogs, cockroaches, rats, and mice. Asthma was diagnosed by study physicians based on caregiver reports of symptoms continually assessed over the course of the study period. Fifty-five of the 299 children developed asthma by the end of the study. Cat exposure had a strong and independent effect to reduce the risk of developing asthma across all analyses (odds ratio [OR], 0.16; 95% confidence interval [CI], 0.05-0.53). Dog, mouse, rat, and cockroach exposures did not significantly influence the development of asthma. Daycare exposure had the largest risk reduction for the development of asthma (OR, 0.08; 95% CI, 0.03-0.19). Maternal asthma (OR, 2.93; 95% CI, 1.29-6.67), baseline body mass index (OR, 1.23; 95% CI, 1.08-1.42), and specific immunoglobulin E to house-dust mix at 3 years were each independent risk factors for the development of asthma. In children with AD, cat and daycare exposure may reduce the risk of developing early childhood asthma.

Previous studies suggest that children with egg allergy may be able to tolerate baked egg. Reliable predictors of a successful baked egg challenge are not well established. We examined egg white-specific IgE levels, skin-prick test (SPT) results, and age as predictors of baked egg oral food challenge (OFC) outcomes. We conducted a retrospective chart review of children, aged 2-18 years, receiving an egg white-specific IgE level, SPT, and OFC to baked egg from 2008 to 2010. Fifty-two oral baked egg challenges were conducted. Of the 52 challenges, 83% (n = 43) passed and 17% (n = 9) failed, including 2 having anaphylaxis. Median SPT wheal size was 12 mm (range, 0-35 mm) for passed challenges and 17 mm (range, 10-30 mm) for failed challenges (p = 0.091). The negative predictive value for passing the OFC was 100% (9 of 9) if SPT wheal size was <10 mm. Median egg white-specific IgE was 2.02 kU/L (range, <0.35-13.00 kU/L) for passed challenges and 1.52 kU/L (range, 0.51-6.10 kU/L) for failed challenges (p = 0.660). Receiver operating characteristic (ROC) curve analysis for SPT revealed an area under the curve (AUC) of 0.64. ROC curve analysis for egg white-specific IgE revealed an AUC of 0.63. There was no significant difference in age between patients who failed and those who passed (median = 8.8 years versus 7.0 years; p = 0.721). Based on our sample, SPT, egg white-specific IgE and age are not good predictors of passing a baked egg challenge. However, there was a trend for more predictability with SPT wheal size.

Background: Children spend a significant amount of time in school. Little is known about the role of allergen exposure in school environments and asthma morbidity., Objectives: The School Inner-City Asthma Study (SICAS) is a National Institutes of Health (NIH)-funded prospective study evaluating the school/classroom-specific risk factors and asthma morbidity among urban children., Methods/results: This article describes the design, methods, and important lessons learned from this extensive investigation. A single center is recruiting 500 elementary school-aged children, all of whom attend inner-city metropolitan schools. The primary hypothesis is that exposure to common indoor allergens in the classroom will increase the risk of asthma morbidity in children with asthma, even after controlling for home allergen exposures. The protocol includes screening surveys of entire schools and baseline eligibility assessments obtained in the spring prior to the academic year. Extensive baseline clinical visits are being conducted among eligible children with asthma during the summer prior to the academic school year. Environmental classroom/school assessments including settled dust and air sampling for allergen, mold, air pollution, and inspection data are collected twice during the academic school year and one home dust sample linked to the enrolled student. Clinical outcomes are measured every 3 months during the academic school year., Conclusion: The overall goal of SICAS is to complete the first study of its kind to better understand school-specific urban environmental factors on childhood asthma morbidity. We also discuss the unique challenges related to school-based urban research and lessons being learned from recruiting such a cohort.

Background: Children with food allergies often have concurrent asthma., Objective: The authors aimed to determine the prevalence of asthma in children with food allergies and the association of specific food allergies with asthma., Methods: Parental questionnaire data regarding food allergy, corroborated by allergic sensitization were completed for a cohort of 799 children with food allergies. Multivariate regression analysis tested the association between food allergy and reported asthma., Results: In this cohort, the prevalence of asthma was 45.6%. After adjusting for each food allergy, environmental allergies, and family history of asthma, children with egg allergy (odds ratio [OR] = 2.0; 95% confidence interval [CI] = 1.3-3.2; P < .01) or tree nut allergy (OR = 2.0; 95% CI = 1.1-3.6; P = .02) had significantly greater odds of report of asthma., Conclusion: There is a high prevalence of asthma in the food-allergic pediatric population. Egg and tree nut allergy are significantly associated with asthma, independent of other risk factors.

Rationale: In 2007 the American Thoracic Society (ATS) recommended guidelines for acceptability and repeatability for assessing spirometry in preschool children. The authors aim to determine the feasibility of spirometry among children in this age group performing spirometry for the first time in a busy clinical practice., Methods: First-time spirometry for children age 4 to 5 years old was selected from the Children's Hospital Boston Pulmonary Function Test (PFT) database. Maneuvers were deemed acceptable if ( 1 ) the flow-volume loop showed rapid rise and smooth descent; ( 2 ) the back extrapolated volume (V(be)), the volume leaked by a subject prior to the forced maneuver, was ≤ 80 ml and 12.5% of forced vital capacity (FVC); and ( 3 ) cessation of expiratory flow was at a point ≤ 10% of peak expiratory flow rate (PEFR). Repeatability was determined by another acceptable maneuver with forced expiratory volume in t seconds (FEV(t)) and FVC within 10% or 0.1 L of the best acceptable maneuver. Post hoc analysis compared spirometry values for those with asthma and cystic fibrosis to normative values., Results: Two hundred and forty-eight preschool children performed spirometry for the first time between August 26, 2006, and August 25, 2008. At least one technically acceptable maneuver was found in 82.3% (n = 204) of the tests performed. Overall, 54% of children were able to perform acceptable and repeatable spirometry based on the ATS criteria. Children with asthma or cystic fibrosis did not have spirometry values that differed significantly from healthy controls. However, up to 29% of the overall cohort displayed at least one abnormal spirometry value., Conclusions: Many preschool-aged children are able to perform technically acceptable and repeatable spirometry under normal conditions in a busy clinical setting. Spirometry may be a useful screen for abnormal lung function in this age group.