HEPA filtration intervention in classrooms may improve some students' asthma.

OBJECTIVE: The School Inner-City Asthma Intervention Study 2 (SICAS 2) tested interventions to reduce exposures in classrooms of students with asthma. The objective of this post-hoc analysis was limited to evaluating the effect of high-efficiency particulate (HEPA) filtration interventions on mold levels as quantified using the Environmental Relative Moldiness Index (ERMI) and the possible improvement in the students' asthma, as quantified by spirometry testing. METHODS: Pre-intervention dust samples were collected at the beginning of the school year from classrooms and corresponding homes of students with asthma (n = 150). Follow-up dust samples were collected in the classrooms at the end of the HEPA or Sham intervention. For each dust sample, ERMI values and the Group 1 and Group 2 mold levels (components of the ERMI metric) were quantified. In addition, each student's lung function was evaluated by spirometry testing, specifically the percentage predicted forced expiratory volume at 1 sec (FEV1%), before and at the end of the intervention. RESULTS: For those students with a higher Group 1 mold level in their pre-intervention classroom than home (n = 94), the FEV1% results for those students was significantly (p < 0.05) inversely correlated with the Group 1 level in their classrooms. After the HEPA intervention, the average Group 1 and ERMI values were significantly lowered, and the average FEV1% test results significantly increased by an average of 4.22% for students in HEPA compared to Sham classrooms. CONCLUSIONS: HEPA intervention in classrooms reduced Group 1 and ERMI values, which corresponded to improvements in the students' FEV1% test results.

A common IL-4 receptor variant promotes asthma severity via a Treg cell GRB2-IL-6-Notch4 circuit.

BACKGROUND: The mechanisms by which genetic and environmental factors interact to promote asthma remain unclear. Both the IL-4 receptor alpha chain R576 (IL-4RαR576) variant and Notch4 license asthmatic lung inflammation by allergens and ambient pollutant particles by subverting lung regulatory T (Treg ) cells in an IL-6-dependent manner. OBJECTIVE: We examined the interaction between IL-4RαR576 and Notch4 in promoting asthmatic inflammation. METHODS: Peripheral blood mononuclear cells (PBMCs) of asthmatics were analyzed for T helper type 2 cytokine production and Notch4 expression on Treg cells as a function of IL4RR576 allele. The capacity of IL-4RαR576 to upregulate Notch4 expression on Treg cells to promote severe allergic airway inflammation was further analyzed in genetic mouse models. RESULTS: Asthmatics carrying the IL4RR576 allele had increased Notch4 expression on their circulating Treg cells as a function of disease severity and serum IL-6. Mice harboring the Il4raR576 allele exhibited increased Notch4-dependent allergic airway inflammation that was inhibited upon Treg cell-specific Notch4 deletion or treatment with an anti-Notch4 antibody. Signaling via IL-4RαR576 upregulated the expression in lung Treg cells of Notch4 and its downstream mediators Yap1 and beta-catenin, leading to exacerbated lung inflammation. This upregulation was dependent on growth factor receptor-bound protein 2 (GRB2) and IL-6 receptor. CONCLUSION: These results identify an IL-4RαR576-regulated GRB2-IL-6-Notch4 circuit that promotes asthma severity by subverting lung Treg cell function.

Atopic Dermatitis Mediates the Association Between an IL4RA Variant and Food Allergy in School-Aged Children.

BACKGROUND: Atopic dermatitis (AD) and food allergy (FA) may share genetic risk factors. It is unknown whether genetic factors directly cause FA or are mediated through AD, as the dual-allergen hypothesis suggests. OBJECTIVE: To test the hypothesis that AD mediates the relationship between an IL-4 receptor alpha chain gene (IL4RA) variant, the human IL-4 receptor alpha chain protein-R576 polymorphism, and FA. METHODS: A total of 433 children with asthma enrolled in the School Inner-City Asthma Study underwent genotyping for the IL4RA576 allele. Surveys were administered to determine FA, AD, and associated allergic responses. Mediation analysis was performed adjusting for race and ethnicity, age, sex, and household income. Multivariate models were used to determine the association between genotype and FA severity. RESULTS: AD was reported in 193 (45%) and FA in 80 children (19%). Each risk allele increased odds of AD 1.39-fold ([1.03-1.87], P = .03), and AD increased odds of FA 3.67-fold ([2.05- 6.57], P < .01). There was an indirect effect of genotype, mediated by AD, predicting FA; each risk allele increased the odds of FA by 1.13 (odds ratio [95% CI], Q/R = 1.13 [1.02-1.24], R/R = 1.28 [1.04-1.51]; P < .01). Each risk allele increased the odds of severe FA symptoms 2.68-fold ([1.26-5.71], P = .01). CONCLUSIONS: In a cohort of children with asthma, AD is part of the causal pathway between an IL4RA variant and FA. This variant is associated with increased risk of severe FA reactions. Addressing AD in children with an IL4RA polymorphism may modulate the risk of FA.

Factors Influencing Classroom Exposures to Fine Particles, Black Carbon, and Nitrogen Dioxide in Inner-City Schools and Their Implications for Indoor Air Quality.

BACKGROUND: School classrooms, where students spend the majority of their time during the day, are the second most important indoor microenvironment for children. OBJECTIVE: We investigated factors influencing classroom exposures to fine particulate matter (PM2.5), black carbon (BC), and nitrogen dioxide (NO2) in urban schools in the northeast United States. METHODS: Over the period of 10 y (2008-2013; 2015-2019) measurements were conducted in 309 classrooms of 74 inner-city schools during fall, winter, and spring of the academic period. The data were analyzed using adaptive mixed-effects least absolute shrinkage and selection operator (LASSO) regression models. The LASSO variables included meteorological-, school-, and classroom-based covariates. RESULTS: LASSO identified 10, 10, and 11 significant factors (p<0.05) that were associated with indoor PM2.5, BC, and NO2 exposures, respectively. The overall variability explained by these models was R2=0.679, 0.687, and 0.621 for PM2.5, BC, and NO2, respectively. Of the model's explained variability, outdoor air pollution was the most important predictor, accounting for 53.9%, 63.4%, and 34.1% of the indoor PM2.5, BC, and NO2 concentrations. School-based predictors included furnace servicing, presence of a basement, annual income, building type, building year of construction, number of classrooms, number of students, and type of ventilation that, in combination, explained 18.6%, 26.1%, and 34.2% of PM2.5, BC, and NO2 levels, whereas classroom-based predictors included classroom floor level, classroom proximity to cafeteria, number of windows, frequency of cleaning, and windows facing the bus area and jointly explained 24.0%, 4.2%, and 29.3% of PM2.5, BC, and NO2 concentrations, respectively. DISCUSSION: The adaptive LASSO technique identified significant regional-, school-, and classroom-based factors influencing classroom air pollutant levels and provided robust estimates that could potentially inform targeted interventions aiming at improving children's health and well-being during their early years of development. https://doi.org/10.1289/EHP10007.

Indoor Environmental Factors May Modify the Response to Mouse Allergen Reduction Among Mouse-Sensitized and Exposed Children with Persistent Asthma.

BACKGROUND: Whether concomitant home exposures modify the effectiveness of mouse allergen reduction among mouse-sensitized children with asthma is unknown. OBJECTIVE: To determine whether a lower baseline home mouse allergen level, lower particulate matter 10 µ or less (PM10), and the absence of sensitization and exposure to other indoor allergens are associated with greater improvements in asthma associated with mouse allergen reduction. METHODS: A secondary analysis of a randomized clinical trial of a home mouse allergen intervention was performed to examine the effect of 3 indoor factors on the relationship between mouse allergen reduction and a range of asthma outcomes. RESULTS: Participants (N = 297) were predominantly minority (78% African American, 22% Hispanic) and publicly insured (88%). Higher baseline mouse allergen levels were associated with a greater response to mouse allergen reduction for several symptom and exacerbation outcomes. Lower indoor PM10 levels were associated with a greater response to mouse allergen reduction for several symptom outcomes, but not exacerbation outcomes. Overall, sensitization and exposure to other indoor allergens did not appear to modify the effect of mouse allergen reduction. CONCLUSIONS: In this population of predominantly low-income children with persistent asthma and mouse sensitization, mouse allergen reduction was associated with improvements in asthma, especially among those with high baseline mouse allergen exposure. Lower indoor PM10 was associated with greater improvements in asthma symptoms.

Effect of School Integrated Pest Management or Classroom Air Filter Purifiers on Asthma Symptoms in Students With Active Asthma: A Randomized Clinical Trial.

Importance: School and classroom allergens and particles are associated with asthma morbidity, but the benefit of environmental remediation is not known. Objective: To determine whether use of a school-wide integrated pest management (IPM) program or high-efficiency particulate air (HEPA) filter purifiers in the classrooms improve asthma symptoms in students with active asthma. Design, Setting, and Participants: Factorial randomized clinical trial of a school-wide IPM program and HEPA filter purifiers in the classrooms was conducted from 2015 to 2020 (School Inner-City Asthma Intervention Study). There were 236 students with active asthma attending 41 participating urban elementary schools located in the Northeastern US who were randomized to IPM by school and HEPA filter purifiers by classroom. The date of final follow-up was June 20, 2020. Interventions: The school-wide IPM program consisted of application of rodenticide, sealing entry points, trap placement, targeted cleaning, and brief educational handouts for school staff. Infestation was assessed every 3 months, with additional treatments as needed. Control schools received no IPM, cleaning, or education. Classroom portable HEPA filter purifiers were deployed and the filters were changed every 3 months. Control classrooms received sham HEPA filters that looked and sounded like active HEPA filter purifiers. Randomization was done independently (split-plot design), with matching by the number of enrolled students to ensure a nearly exact 1:1 student ratio for each intervention with 118 students randomized to each group. Participants, investigators, and those assessing outcomes were blinded to the interventions. Main Outcomes and Measures: The primary outcome was the number of symptom-days with asthma during a 2-week period. Symptom-days were assessed every 2 months during the 10 months after randomization. Results: Among the 236 students who were randomized (mean age, 8.1 [SD, 2.0] years; 113 [48%] female), all completed the trial. At baseline, the 2-week mean was 2.2 (SD, 3.9) symptom-days with asthma and 98% of the classrooms had detectable levels of mouse allergen. The results were pooled because there was no statistically significant difference between the 2 interventions (P = .18 for interaction). During a 2-week period, the mean was 1.5 symptom-days with asthma after use of the school-wide IPM program vs 1.9 symptom-days after no IPM across the school year (incidence rate ratio, 0.71 [95% CI, 0.38-1.33]), which was not statistically significantly different. During a 2-week period, the mean was 1.6 symptom-days with asthma after use of HEPA filter purifiers in the classrooms vs 1.8 symptom-days after use of sham HEPA filter purifiers across the school year (incidence rate ratio, 1.47 [95% CI, 0.79-2.75]), which was not statistically significantly different. There were no intervention-related adverse events. Conclusions and Relevance: Among children with active asthma, use of a school-wide IPM program or classroom HEPA filter purifiers did not significantly reduce symptom-days with asthma. However, interpretation of the study findings may need to consider allergen levels, particle exposures, and asthma symptoms at baseline. Trial Registration: ClinicalTrials.gov Identifier: NCT02291302.

Isolation and characterization of extracellular vesicles in saliva of children with asthma.

AIM: To confirm the presence of extracellular vesicles (EVs) in cell-free saliva (CFS) of children with asthma and describe the isolated EV population. METHODS: A pooled sample of CFS EVs isolated from 180 participants using ExoQuick-TC was examined in downstream analyses. Transmission electron microscopy (TEM) was used to confirm the presence of EVs. Nanoparticle tracking analysis (NTA) and single particle interferometric reflectance imaging sensing (SP-IRIS) with fluorescence were used for sizing, counting, and phenotyping of EVs. Capillary immunoassays were used for protein quantitation. RESULTS: TEM confirmed the presence of EVs of diverse sizes, indicating the prep contained a heterogeneous population of EVs. Capillary immunoassays confirmed the presence of EV-associated proteins (CD9, CD63, CD81, ICAM-1, and ANXA5) and indicated limited cellular contamination. As others have also reported, there were discrepancies in the EV sizing and enumeration across platforms. Fluorescent NTA detected particles with a mode diameter of ~90 nm, whereas SP-IRIS reported sizes of ~55-60 nm that more closely approximated the TEM results. Consistent with protein immunoassay results, SP-IRIS with fluorescence showed that the majority of these EVs were CD9- and CD63-positive, with little expression of CD81. CONCLUSION: EVs from CFS can be isolated using a high-throughput method that can be scaled to large epidemiological studies. To our knowledge, we are the first to characterize CFS EVs from patients with asthma. The use of CFS EVs as potential novel biomarkers in asthma warrants further investigation and opens a new avenue of research for future studies.

Air quality, Environment and Respiratory Outcomes in Bronchopulmonary Dysplasia, the AERO-BPD cohort study: design and adaptation during the SARS-CoV-2 pandemic.

INTRODUCTION: Almost half of all school-age children with bronchopulmonary dysplasia (BPD) have asthma-like symptoms and more suffer from lung function deficits. While air pollution and indoor respiratory irritants are known to affect high-risk populations of children, few studies have objectively evaluated environmental contributions to long-term respiratory morbidity in this population. This study aimed to examine the role of indoor environmental exposures on respiratory morbidity in children with BPD. METHODS AND ANALYSIS: The Air quality, Environment and Respiratory Ouctomes in BPD (AERO-BPD) study is a prospective, single-centre observational study that will enrol a unique cohort of 240 children with BPD and carefully characterise participants and their indoor home environmental exposures. Measures of indoor air quality constituents will assess the relationship of nitrogen dioxide (NO2), particulate matter (PM2.5), nitric oxide (NO), temperature and humidity, as well as dust concentrations of allergens, with concurrently measured respiratory symptoms and lung function.Adaptations to the research protocol due to the SARS-CoV-2 pandemic included remote home environment and participant assessments. ETHICS AND DISSEMINATION: Study protocol was approved by the Boston Children's Hospital Committee on Clinical Investigation. Dissemination will be in the form of peer-reviewed publications and participant information products. TRIAL REGISTRATION NUMBER: NCT04107701.

Asthma Prevalence and Mold Levels in US Northeastern Schools.

BACKGROUND: Asthma is among the most common chronic diseases of children in the United States (US). Mold exposures have been linked to asthma development and exacerbation. In homes, mold exposures have been quantified using the Environmental Relative Moldiness Index (ERMI), and higher home ERMI values have been linked to occupant asthma. OBJECTIVE: In this analysis of the School Inner-City Asthma Study (SICAS), we aimed to evaluate the ERMI's applicability to measuring mold in schools compared with homes and to examine the prevalence of asthma in relationship to students' demographics and the physical characteristics of school buildings. METHODS: Northeastern US schools (n = 32) and homes (n = 33) were selected, and the 36 ERMI molds were quantified in a dust sample from each classroom (n = 114) or home. School building characteristics data were collected from SICAS. Asthma prevalence and student demographics data were obtained from government websites. Linear regression and mixed models were fit to assess the association of the current asthma prevalence and physical characteristics of the school, make-up of the student body, and the ERMI metric. RESULTS: Levels of outdoor group 2 molds were significantly (P < .01) greater in schools compared with homes. The presence of air-conditioning in school buildings correlated significantly (P = .02) with lower asthma prevalence. CONCLUSION: The prevalence of asthma in student bodies is associated with many factors in schools and homes.

Preventing asthma in high risk kids (PARK) with omalizumab: Design, rationale, methods, lessons learned and adaptation.

Asthma remains one of the most important challenges to pediatric public health in the US. A large majority of children with persistent and chronic asthma demonstrate aeroallergen sensitization, which remains a pivotal risk factor associated with the development of persistent, progressive asthma throughout life. In individuals with a tendency toward Type 2 inflammation, sensitization and exposure to high concentrations of offending allergens is associated with increased risk for development of, and impairment from, asthma. The cascade of biological responses to allergens is primarily mediated through IgE antibodies and their production is further stimulated by IgE responses to antigen exposure. In addition, circulating IgE impairs innate anti-viral immune responses. The latter effect could magnify the effects of another early life exposure associated with increased risk of the development of asthma - viral infections. Omalizumab binds to circulating IgE and thus ablates antigen signaling through IgE-related mechanisms. Further, it has been shown restore IFN-α response to rhinovirus and to reduce asthma exacerbations during the viral season. We therefore hypothesized that early blockade of IgE and IgE mediated responses with omalizumab would prevent the development and reduce the severity of asthma in those at high risk for developing asthma. Herein, we describe a double-blind, placebo-controlled trial of omalizumab in 2-3 year old children at high risk for development of asthma to prevent the development and reduce the severity of asthma. We describe the rationale, methods, and lessons learned in implementing this potentially transformative trial aimed at prevention of asthma.

Do Baseline Asthma and Allergic Sensitization Characteristics Predict Responsiveness to Mouse Allergen Reduction?

BACKGROUND: Mouse allergen reduction is associated with improvements in asthma among sensitized and exposed children, but whether clinical characteristics predict responsiveness to allergen reduction is unclear. OBJECTIVE: To examine the effects of clinical characteristics on relationships between mouse allergen reduction and asthma outcomes. METHODS: We performed a secondary analysis of data from a randomized clinical trial of a mouse allergen intervention, examining the effects of atopy, demographic characteristics, lung function, asthma control, and asthma severity on relationships between mouse allergen reduction and asthma outcomes. RESULTS: Participants were predominantly low-income and minority (78% black, 22% Hispanic), and had persistent asthma. Among less atopic participants (<6 positive skin prick test results), each 50% reduction in mouse allergen was associated with fewer symptoms (incidence rate ratio [95% CI]: maximal symptoms: 0.94 [0.92-0.96]). There was little effect of mouse allergen reduction on symptoms among more atopic participants (P > .05). The interactions between atopic status and mouse allergen reduction were statistically significant for all symptom outcomes; however, there was no evidence that atopic status influenced the effect of mouse allergen reduction on exacerbation-related outcomes. Older children (≥9 years) tended to experience greater improvement in some asthma outcomes with reduction in mouse allergen exposure than younger children. There was no evidence that either mouse-specific IgE or lung function influenced the effect of mouse allergen reduction on any asthma outcomes. CONCLUSIONS: Although there may be variability in the clinical response to mouse allergen reduction among low-income, minority children with asthma, there were no clinical characteristics that clearly identified a subgroup at which the intervention should be targeted.

Reduction in mouse allergen exposure is associated with greater lung function growth.

BACKGROUND: Current childhood asthma therapies have little effect on lung function trajectory. OBJECTIVE: We sought to determine whether mouse allergen exposure reduction is associated with lung function growth in mouse-sensitized/exposed asthmatic children. METHODS: Three hundred fifty mouse-sensitized/exposed asthmatic children (5-17 years old) were enrolled in a 1-year randomized trial of integrated pest management plus education versus education alone. Prebronchodilator/postbronchodilator spirometry was performed at baseline and 6 and 12 months, and bedroom floor mouse allergen levels were measured every 3 months. Mouse allergen reduction was defined as a 75% or greater decrease in mouse allergen levels from baseline. Treatment groups were combined for analyses because there were no differences in outcomes between groups. Changes in lung function over time were modeled, adjusting for age, sex, race, atopy, group, and bronchodilator reversibility and including an interaction term (allergen reduction*time). RESULTS: The study population was predominantly black (79.4%) and low income (66.3% [<$30,000]). At baseline, the median mouse allergen level was 5.7 µg/g (interquartile range, 1.5-22.8 µg/g), and the mean (SD) prebronchodilator FEV1/forced vital capacity ratio was 80.2% (9.0%). Ninety-two (26.3%) participants had 75% or greater reduction in mouse allergen levels. For a 10-year-old black boy, 75% or greater allergen reduction was associated with an increase in prebronchodilator FEV1 of 238 mL/y (95% CI, 177-299 mL/y), whereas less than 75% allergen reduction was associated with an increase in prebronchodilator FEV1 of 131 mL/y (95% CI, 97-166 mL/y). Estimated differences in prebronchodilator and postbronchodilator FEV1 growth were as follows: 107 mL/y (95% CI, 37-177 mL/y; Pint = .003) and 48 mL/y (95% CI, -17 to 113 mL/y; Pint = .15), respectively. Estimated differences in prebronchodilator and postbronchodilator forced expiratory flow at 25% to 75% of vital capacity growth were as follows: 182 mL/y (95% CI, 61-304 mL/y; Pint = .003) and 181 mL/y (95% CI, 48-314 mL/y; Pint = .008), respectively. CONCLUSION: Mouse allergen reduction is associated with greater increases in prebronchodilator FEV1 and prebronchodilator/postbronchodilator forced expiratory flow at 25% to 75% of vital capacity over 1 year among sensitized/exposed asthmatic children.

Caregiver-Reported Asthma Control Predicts Future Visits, Independent of Guideline-Based Control Measures.

BACKGROUND: It is unknown whether caregiver perception of a child's asthma control, independent of guideline-based asthma control assessment, is a predictor of future acute visits. OBJECTIVE: To determine whether caregiver-reported asthma control is an indicator of future risk of acute visit. METHODS: Two study populations of low-income, minority 5- to 17-year-old children with persistent asthma were included. Questionnaires administered at baseline and at 3, 6, 9, and 12 months captured symptoms, short-acting ß-agonist use, acute visits in the previous 3 months, and caregiver-reported asthma control. Well-controlled, not well-controlled, and very poorly controlled asthma were defined using National Asthma Education and Prevention Program guideline-based assessment. Relationships between caregiver-reported control and acute visits in the subsequent 3 months were examined. RESULTS: At baseline, both populations were predominantly black/African American (91% and 79%) with public insurance (85% and 88%) and very poorly controlled asthma (47% and 50%). In both populations, most caregivers reported that their child's asthma was well controlled (73% and 69%). In both populations, participants whose caregivers reported that their child had uncontrolled asthma had greater odds of having an acute visit in the following 3 months as compared with participants whose caregivers reported that their child's asthma was well controlled, independent of guideline-based control, age, sex, race, controller medication, insurance, and atopy (odds ratio [95% CI], 2.4 [1.4-4.2] and 1.6 [1.1-2.4]). CONCLUSIONS: Among predominantly low-income minority children with asthma, caregiver-reported asthma control may provide information about the risk of future acute visit for asthma that is complementary to guideline-based control assessment.

The School Inner-City Asthma Intervention Study: Design, rationale, methods, and lessons learned.

Asthma is the most common chronic disease of childhood in the United States, causes significant morbidity, particularly in the inner-city, and accounts for billions of dollars in health care utilization. Home environments are established sources of exposure that exacerbate symptoms and home-based interventions are effective. However, elementary school children spend 7 to 12h a day in school, primarily in one classroom. From the observational School Inner-City Asthma Study we learned that student classroom-specific exposures are associated with worsening asthma symptoms and decline in lung function. We now embark on a randomized, blinded, sham-controlled school environmental intervention trial, built on our extensively established school/community partnerships, to determine the efficacy of a school-based intervention to improve asthma control. This factorial school/classroom based environmental intervention will plan to enroll 300 students with asthma from multiple classrooms in 40 northeastern inner-city elementary schools. Schools will be randomized to receive either integrated pest management versus control and classrooms within these schools to receive either air purifiers or sham control. The primary outcome is asthma symptoms during the school year. This study is an unprecedented opportunity to test whether a community of children can benefit from school or classroom environmental interventions. If effective, this will have great impact as an efficient, cost-effective intervention for inner city children with asthma and may have broad public policy implications.

Effect of an Integrated Pest Management Intervention on Asthma Symptoms Among Mouse-Sensitized Children and Adolescents With Asthma: A Randomized Clinical Trial.

Importance: Professionally delivered integrated pest management (IPM) interventions can reduce home mouse allergen concentrations, but whether they reduce asthma morbidity among mouse-sensitized and exposed children and adolescents is unknown. Objective: To determine the effect of an IPM intervention on asthma morbidity among mouse-sensitized and exposed children and adolescents with asthma. Design, Setting, and Participants: Randomized clinical trial conducted in Baltimore, Maryland, and Boston, Massachusetts. Participants were mouse-sensitized and exposed children and adolescents (aged 5-17 years) with asthma randomized to receive professionally delivered IPM plus pest management education or pest management education alone. Enrollment occurred between May 2010 and August 2014; the final follow-up visit occurred on September 25, 2015. Interventions: Integrated pest management consisted of application of rodenticide, sealing of holes that could serve as entry points for mice, trap placement, targeted cleaning, allergen-proof mattress and pillow encasements, and portable air purifiers. Infestation was assessed every 3 months, and if infestation persisted or recurred, additional treatments were delivered. All participants received pest management education, which consisted of written material and demonstration of the materials needed to set traps and seal holes. Main Outcomes and Measures: The primary outcome was maximal symptom days defined as the highest number of days of symptoms in the previous 2 weeks among 3 types of symptoms (days of slowed activity due to asthma; number of nights of waking with asthma symptoms; and days of coughing, wheezing, or chest tightness) across 6, 9, and 12 months. Results: Of 361 children and adolescents who were randomized (mean [SD] age, 9.8 [3.2] years; 38% female; 181 in IPM plus pest management education group and 180 in pest management education alone group), 334 were included in the primary analysis. For the primary outcome, there was no statistically significant between-group difference for maximal symptom days across 6, 9, and 12 months with a median of 2.0 (interquartile range, 0.7-4.7) maximal symptom days in the IPM plus pest management education group and 2.7 (interquartile range, 1.3-5.0) maximal symptom days in the pest management education alone group (P = .16) and a ratio of symptom frequencies of 0.86 (95% CI, 0.69-1.06). Conclusions and Relevance: Among mouse-sensitized and exposed children and adolescents with asthma, an intensive year-long integrated pest management intervention plus pest management education vs pest management education alone resulted in no significant difference in maximal symptom days from 6 to 12 months. Trial Registration: clinicaltrials.gov Identifier: NCT01251224.