Early-Life Exposure to Air Pollution and Childhood Asthma Cumulative Incidence in the ECHO CREW Consortium

Importance

Exposure to outdoor air pollution contributes to childhood asthma development, but many studies lack the geographic, racial and ethnic, and socioeconomic diversity to evaluate susceptibility by individual-level and community-level contextual factors.

Objective

To examine early life exposure to fine particulate matter (PM2.5) and nitrogen oxide (NO2) air pollution and asthma risk by early and middle childhood, and whether individual and community-level characteristics modify associations between air pollution exposure and asthma.

Design, Setting, and Participants

This cohort study included children enrolled in cohorts participating in the Children's Respiratory and Environmental Workgroup consortium. The birth cohorts were located throughout the US, recruited between 1987 and 2007, and followed up through age 11 years. The survival analysis was adjusted for mother's education, parental asthma, smoking during pregnancy, child's race and ethnicity, sex, neighborhood characteristics, and cohort. Statistical analysis was performed from February 2022 to December 2023.

Exposure

Early-life exposures to PM2.5 and NO2 according to participants' birth address.

Main Outcomes and Measures

Caregiver report of physician-diagnosed asthma through early (age 4 years) and middle (age 11 years) childhood.

Results

Among 5279 children included, 1659 (31.4%) were Black, 835 (15.8%) were Hispanic, 2555 (48.4%) where White, and 229 (4.3%) were other race or ethnicity; 2721 (51.5%) were male and 2596 (49.2%) were female; 1305 children (24.7%) had asthma by 11 years of age and 954 (18.1%) had asthma by 4 years of age. Mean values of pollutants over the first 3 years of life were associated with asthma incidence. A 1 IQR increase in NO2 (6.1 μg/m3) was associated with increased asthma incidence among children younger than 5 years (HR, 1.25 [95% CI, 1.03-1.52]) and children younger than 11 years (HR, 1.22 [95% CI, 1.04-1.44]). A 1 IQR increase in PM2.5 (3.4 μg/m3) was associated with increased asthma incidence among children younger than 5 years (HR, 1.31 [95% CI, 1.04-1.66]) and children younger than 11 years (OR, 1.23 [95% CI, 1.01-1.50]). Associations of PM2.5 or NO2 with asthma were increased when mothers had less than a high school diploma, among Black children, in communities with fewer child opportunities, and in census tracts with higher percentage Black population and population density; for example, there was a significantly higher association between PM2.5 and asthma incidence by younger than 5 years of age in Black children (HR, 1.60 [95% CI, 1.15-2.22]) compared with White children (HR, 1.17 [95% CI, 0.90-1.52]).

Conclusions and Relevance

In this cohort study, early life air pollution was associated with increased asthma incidence by early and middle childhood, with higher risk among minoritized families living in urban communities characterized by fewer opportunities and resources and multiple environmental coexposures. Reducing asthma risk in the US requires air pollution regulation and reduction combined with greater environmental, educational, and health equity at the community level.

The impact of prenatal dog keeping on infant gut microbiota development

INTRODUCTION

Prenatal and early-life dog exposure has been linked to reduced childhood allergy and asthma. A potential mechanism includes altered early immune development in response to changes in the gut microbiome among dog-exposed infants. We thus sought to determine whether infants born into homes with indoor dog(s) exhibit altered gut microbiome development.

METHODS

Pregnant women living in homes with dogs or in pet-free homes were recruited in southeast Michigan. Infant stool samples were collected at intervals between 1 week and 18 months after birth and microbiome was assessed using 16S ribosomal sequencing. Perinatal maternal vaginal/rectal swabs and stool samples were sequenced from a limited number of mothers. Mixed effect adjusted models were used to assess stool microbial community trajectories comparing infants from dog-keeping versus pet-free homes with adjustment for relevant covariates.

RESULTS

Infant gut microbial composition among vaginally born babies became less similar to the maternal vaginal/rectal microbiota and more similar to the maternal gut microbiota with age-related accumulation of bacterial species with advancing age. Stool samples from dog-exposed infants were microbially more diverse (p = .041) through age 18 months with enhanced diversity most apparent between 3 and 6 months of age. Statistically significant effects of dog exposure on β-diversity metrics were restricted to formula-fed children. Across the sample collection period, dog exposure was associated with Fusobacterium genera enrichment, as well as enrichment of Collinsella, Ruminococcus, Clostridaceae and Lachnospiraceae OTUs.

CONCLUSION

Prenatal/early-life dog exposure is associated with an altered gut microbiome during infancy and supports a potential mechanism explaining lessened atopy and asthma risk. Further research directly linking specific dog-attributable changes in the infant gut microbiome to the risk of allergic disorders is needed.

Associations between outdoor air pollutants and non-viral asthma exacerbations and airway inflammatory responses in children and adolescents living in urban areas in the USA: a retrospective secondary analysis

BACKGROUND

Asthma prevalence and severity have markedly increased with urbanisation, and children in low-income urban centres have among the greatest asthma morbidity. Outdoor air pollution has been associated with adverse respiratory effects in children with asthma. However, the mechanisms by which air pollution exposure exacerbates asthma, and how these mechanisms compare with exacerbations induced by respiratory viruses, are poorly understood. We aimed to investigate the associations between regional air pollutant concentrations, respiratory illnesses, lung function, and upper airway transcriptional signatures in children with asthma, with particular focus on asthma exacerbations occurring in the absence of respiratory virus.

METHODS

We performed a retrospective analysis of data from the MUPPITS1 cohort and validated our findings in the ICATA cohort. The MUPPITS1 cohort recruited 208 children aged 6-17 years living in urban areas across nine US cities with exacerbation-prone asthma between Oct 7, 2015, and Oct 18, 2016, and monitored them during reported respiratory illnesses. The last MUPPITS1 study visit occurred on Jan 6, 2017. The ICATA cohort recruited 419 participants aged 6-20 years with persistent allergic asthma living in urban sites across eight US cities between Oct 23, 2006, and March 25, 2008, and the last study visit occurred on Dec 30, 2009. We included participants from the MUPPITS1 cohort who reported a respiratory illness at some point during the follow-up and participants from the ICATA cohort who had nasal samples collected during respiratory illness or at a scheduled visit. We used air quality index values and air pollutant concentrations for PM2·5, PM10, O3, NO2, SO2, CO, and Pb from the US Environmental Protection Agency spanning the years of both cohorts, and matched values and concentrations to each illness for each participant. We investigated the associations between regional air pollutant concentrations and respiratory illnesses and asthma exacerbations, pulmonary function, and upper airway transcriptional signatures by use of a combination of generalised additive models, case crossover analyses, and generalised linear mixed-effects models.

FINDINGS

Of the 208 participants from the MUPPITS1 cohort and 419 participants from the ICATA cohort, 168 participants in the MUPPITS1 cohort (98 male participants and 70 female participants) and 189 participants in the ICATA cohort (115 male participants and 74 female participants) were included in our analysis. We identified that increased air quality index values, driven predominantly by increased PM2·5 and O3 concentrations, were significantly associated with asthma exacerbations and decreases in pulmonary function that occurred in the absence of a provoking viral infection. Moreover, individual pollutants were significantly associated with altered gene expression in coordinated inflammatory pathways, including PM2·5 with increased epithelial induction of tissue kallikreins, mucus hypersecretion, and barrier functions and O3 with increased type-2 inflammation.

INTERPRETATION

Our findings suggest that air pollution is an important independent risk factor for asthma exacerbations in children living in urban areas and is potentially linked to exacerbations through specific inflammatory pathways in the airway. Further investigation of these potential mechanistic pathways could inform asthma prevention and management approaches.

FUNDING

National Institutes of Health, National Institute of Allergy and Infectious Diseases.

Association of citrulline concentration at birth with lower respiratory tract infection in infancy: Findings from a multi-site birth cohort study

Assessing the association of the newborn metabolic state with severity of subsequent respiratory tract infection may provide important insights on infection pathogenesis. In this multi-site birth cohort study, we identified newborn metabolites associated with lower respiratory tract infection (LRTI) in the first year of life in a discovery cohort and assessed for replication in two independent cohorts. Increased citrulline concentration was associated with decreased odds of LRTI (discovery cohort: aOR 0.83 [95% CI 0.70-0.99], p = 0.04; replication cohorts: aOR 0.58 [95% CI 0.28-1.22], p = 0.15). While our findings require further replication and investigation of mechanisms of action, they identify a novel target for LRTI prevention and treatment.

African-specific alleles modify risk for asthma at the 17q12-q21 locus in African Americans

BACKGROUND

Asthma is the most common chronic disease in children, occurring at higher frequencies and with more severe disease in children with African ancestry.

METHODS

We tested for association with haplotypes at the most replicated and significant childhood-onset asthma locus at 17q12-q21 and asthma in European American and African American children. Following this, we used whole-genome sequencing data from 1060 African American and 100 European American individuals to identify novel variants on a high-risk African American-specific haplotype. We characterized these variants in silico using gene expression and ATAC-seq data from airway epithelial cells, functional annotations from ENCODE, and promoter capture (pc)Hi-C maps in airway epithelial cells. Candidate causal variants were then assessed for correlation with asthma-associated phenotypes in African American children and adults.

RESULTS

Our studies revealed nine novel African-specific common variants, enriched on a high-risk asthma haplotype, which regulated the expression of GSDMA in airway epithelial cells and were associated with features of severe asthma. Using ENCODE annotations, ATAC-seq, and pcHi-C, we narrowed the associations to two candidate causal variants that are associated with features of T2 low severe asthma.

CONCLUSIONS

Previously unknown genetic variation at the 17q12-21 childhood-onset asthma locus contributes to asthma severity in individuals with African ancestries. We suggest that many other population-specific variants that have not been discovered in GWAS contribute to the genetic risk for asthma and other common diseases.

Mepolizumab for urban children with exacerbation-prone eosinophilic asthma in the USA (MUPPITS-2): a randomised, double-blind, placebo-controlled, parallel-group trial

BACKGROUND

Black and Hispanic children living in urban environments in the USA have an excess burden of morbidity and mortality from asthma. Therapies directed at the eosinophilic phenotype reduce asthma exacerbations in adults, but few data are available in children and diverse populations. Furthermore, the molecular mechanisms that underlie exacerbations either being prevented by, or persisting despite, immune-based therapies are not well understood. We aimed to determine whether mepolizumab, added to guidelines-based care, reduced the number of asthma exacerbations during a 52-week period compared with guidelines-based care alone.

METHODS

This is a randomised, double-blind, placebo-controlled, parallel-group trial done at nine urban medical centres in the USA. Children and adolescents aged 6-17 years, who lived in socioeconomically disadvantaged neighbourhoods and had exacerbation-prone asthma (defined as ≥two exacerbations in the previous year) and blood eosinophils of at least 150 cells per μL were randomly assigned 1:1 to mepolizumab (6-11 years: 40 mg; 12-17 years: 100 mg) or placebo injections once every 4 weeks, plus guideline-based care, for 52 weeks. Randomisation was done using a validated automated system. Participants, investigators, and the research staff who collected outcome measures remained masked to group assignments. The primary outcome was the number of asthma exacerbations that were treated with systemic corticosteroids during 52 weeks in the intention-to-treat population. The mechanisms of treatment response were assessed by study investigators using nasal transcriptomic modular analysis. Safety was assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT03292588.

FINDINGS

Between Nov 1, 2017, and Mar 12, 2020, we recruited 585 children and adolescents. We screened 390 individuals, of whom 335 met the inclusion criteria and were enrolled. 290 met the randomisation criteria, were randomly assigned to mepolizumab (n=146) or placebo (n=144), and were included in the intention-to-treat analysis. 248 completed the study. The mean number of asthma exacerbations within the 52-week study period was 0·96 (95% CI 0·78-1·17) with mepolizumab and 1·30 (1·08-1·57) with placebo (rate ratio 0·73; 0·56-0·96; p=0·027). Treatment-emergent adverse events occurred in 42 (29%) of 146 participants in the mepolizumab group versus 16 (11%) of 144 participants in the placebo group. No deaths were attributed to mepolizumab.

INTERPRETATION

Phenotype-directed therapy with mepolizumab in urban children with exacerbation-prone eosinophilic asthma reduced the number of exacerbations.

FUNDING

US National Institute of Allergy and Infectious Diseases and GlaxoSmithKline.

Childhood Asthma Incidence, Early and Persistent Wheeze, and Neighborhood Socioeconomic Factors in the ECHO/CREW Consortium

Importance

In the United States, Black and Hispanic children have higher rates of asthma and asthma-related morbidity compared with White children and disproportionately reside in communities with economic deprivation.

Objective

To determine the extent to which neighborhood-level socioeconomic indicators explain racial and ethnic disparities in childhood wheezing and asthma.

Design, Setting, and Participants

The study population comprised children in birth cohorts located throughout the United States that are part of the Children's Respiratory and Environmental Workgroup consortium. Cox proportional hazard models were used to estimate hazard ratios (HRs) of asthma incidence, and logistic regression was used to estimate odds ratios of early and persistent wheeze prevalence accounting for mother's education, parental asthma, smoking during pregnancy, child's race and ethnicity, sex, and region and decade of birth.

Exposures

Neighborhood-level socioeconomic indicators defined by US census tracts calculated as z scores for multiple tract-level variables relative to the US average linked to participants' birth record address and decade of birth. The parent or caregiver reported the child's race and ethnicity.

Main Outcomes and Measures

Prevalence of early and persistent childhood wheeze and asthma incidence.

Results

Of 5809 children, 46% reported wheezing before age 2 years, and 26% reported persistent wheeze through age 11 years. Asthma prevalence by age 11 years varied by cohort, with an overall median prevalence of 25%. Black children (HR, 1.47; 95% CI, 1.26-1.73) and Hispanic children (HR, 1.29; 95% CI, 1.09-1.53) were at significantly increased risk for asthma incidence compared with White children, with onset occurring earlier in childhood. Children born in tracts with a greater proportion of low-income households, population density, and poverty had increased asthma incidence. Results for early and persistent wheeze were similar. In effect modification analysis, census variables did not significantly modify the association between race and ethnicity and risk for asthma incidence; Black and Hispanic children remained at higher risk for asthma compared with White children across census tracts socioeconomic levels.

Conclusions and Relevance

Adjusting for individual-level characteristics, we observed neighborhood socioeconomic disparities in childhood wheeze and asthma. Black and Hispanic children had more asthma in neighborhoods of all income levels. Neighborhood- and individual-level characteristics and their root causes should be considered as sources of respiratory health inequities.

Risk factors for SARS-CoV-2 infection and transmission in households with children with asthma and allergy: A prospective surveillance study

BACKGROUND

Whether children and people with asthma and allergic diseases are at increased risk for severe acute respiratory syndrome virus 2 (SARS-CoV-2) infection is unknown.

OBJECTIVE

Our aims were to determine the incidence of SARS-CoV-2 infection in households with children and to also determine whether self-reported asthma and/or other allergic diseases are associated with infection and household transmission.

METHODS

For 6 months, biweekly nasal swabs and weekly surveys were conducted within 1394 households (N = 4142 participants) to identify incident SARS-CoV-2 infections from May 2020 to February 2021, which was the pandemic period largely before a vaccine and before the emergence of SARS-CoV-2 variants. Participant and household infection and household transmission probabilities were calculated by using time-to-event analyses, and factors associated with infection and transmission risk were determined by using regression analyses.

RESULTS

In all, 147 households (261 participants) tested positive for SARS-CoV-2. The household SARS-CoV-2 infection probability was 25.8%; the participant infection probability was similar for children (14.0% [95% CI = 8.0%-19.6%]), teenagers (12.1% [95% CI = 8.2%-15.9%]), and adults (14.0% [95% CI = 9.5%-18.4%]). Infections were symptomatic in 24.5% of children, 41.2% of teenagers, and 62.5% of adults. Self-reported doctor-diagnosed asthma was not a risk factor for infection (adjusted hazard ratio [aHR] = 1.04 [95% CI = 0.73-1.46]), nor was upper respiratory allergy or eczema. Self-reported doctor-diagnosed food allergy was associated with lower infection risk (aHR = 0.50 [95% CI = 0.32-0.81]); higher body mass index was associated with increased infection risk (aHR per 10-point increase = 1.09 [95% CI = 1.03-1.15]). The household secondary attack rate was 57.7%. Asthma was not associated with household transmission, but transmission was lower in households with food allergy (adjusted odds ratio = 0.43 [95% CI = 0.19-0.96]; P = .04).

CONCLUSION

Asthma does not increase the risk of SARS-CoV-2 infection. Food allergy is associated with lower infection risk, whereas body mass index is associated with increased infection risk. Understanding how these factors modify infection risk may offer new avenues for preventing infection.

Human Epidemiology and RespOnse to SARS-CoV-2 (HEROS): Objectives, Design and Enrollment Results of a 12-City Remote Observational Surveillance Study of Households with Children using Direct-to-Participant Methods

The Human Epidemiology and Response to SARS-CoV-2 (HEROS) is a prospective multi-city 6-month incidence study which was conducted from May 2020-February 2021. The objectives were to identify risk factors for SARS-CoV-2 infection and household transmission among children and people with asthma and allergic diseases, and to use the host nasal transcriptome sampled longitudinally to understand infection risk and sequelae at the molecular level. To overcome challenges of clinical study implementation due to the coronavirus pandemic, this surveillance study used direct-to-participant methods to remotely enroll and prospectively follow eligible children who are participants in other NIH-funded pediatric research studies and their household members. Households participated in weekly surveys and biweekly nasal sampling regardless of symptoms. The aim of this report is to widely share the methods and study instruments and to describe the rationale, design, execution, logistics and characteristics of a large, observational, household-based, remote cohort study of SARS-CoV-2 infection and transmission in households with children. The study enrolled a total of 5,598 individuals, including 1,913 principal participants (children), 1,913 primary caregivers, 729 secondary caregivers and 1,043 other household children. This study was successfully implemented without necessitating any in-person research visits and provides an approach for rapid execution of clinical research.

Association of mold levels in urban children's homes with difficult-to-control asthma

BACKGROUND

Mold sensitization and exposure are associated with asthma severity, but the specific species that contribute to difficult-to-control (DTC) asthma are unknown.

OBJECTIVE

We sought to determine the association between overall and specific mold levels in the homes of urban children and DTC asthma.

METHODS

The Asthma Phenotypes in the Inner-City study recruited participants, aged 6 to 17 years, from 8 US cities and classified each participant as having either DTC asthma or easy-to-control (ETC) asthma on the basis of treatment step level. Dust samples had been collected in each participant's home (n = 485), and any dust remaining (n = 265 samples), after other analyses, was frozen at -20^oC. The dust samples (n = 265) were analyzed using quantitative PCR to determine the concentrations of the 36 molds in the Environmental Relative Moldiness Index. Logistic regression was performed to discriminate specific mold content of dust from homes of children with DTC versus ETC asthma.

RESULTS

Frozen-dust samples were available from 54% of homes of children with DTC (139 of 253) and ETC asthma (126 of 232). Only the average concentration of the mold Mucor was significantly (P < .001) greater in homes of children with DTC asthma. In homes with window air-conditioning units, the Mucor concentration contributed about a 22% increase (1.6 odds ratio; 95% CI, 1.2-2.2) in the ability to discriminate between cases of DTC and ETC asthma.

CONCLUSIONS

Mucor levels in the homes of urban youth were a predictor of DTC asthma, and these higher Mucor levels were more likely in homes with a window air-conditioner.

COVID-19 Modulates Inflammatory and Renal Markers That May Predict Hospital Outcomes among African American Males

Background and Objectives: African Americans and males have elevated risks of infection, hospitalization, and death from SARS-CoV-2 in comparison with other populations. We report immune responses and renal injury markers in African American male patients hospitalized for COVID-19. Methods: This was a single-center, retrospective study of 56 COVID-19 infected hospitalized African American males 50+ years of age selected from among non-intensive care unit (ICU) and ICU status patients. Demographics, hospitalization-related variables, and medical history were collected from electronic medical records. Plasma samples collected close to admission (≤2 days) were evaluated for cytokines and renal markers; results were compared to a control group (n = 31) and related to COVID-19 in-hospital mortality. Results: Among COVID-19 patients, eight (14.2%) suffered in-hospital mortality; seven (23.3%) in the ICU and one (3.8%) among non-ICU patients. Interleukin (IL)-18 and IL-33 were elevated at admission in COVID-19 patients in comparison with controls. IL-6, IL-18, MCP-1/CCL2, MIP-1α/CCL3, IL-33, GST, and osteopontin were upregulated at admission in ICU patients in comparison with controls. In addition to clinical factors, MCP-1 and GST may provide incremental value for risk prediction of COVID-19 in-hospital mortality. Conclusions: Qualitatively similar inflammatory responses were observed in comparison to other populations reported in the literature, suggesting non-immunologic factors may account for outcome differences. Further, we provide initial evidence for cytokine and renal toxicity markers as prognostic factors for COVID-19 in-hospital mortality among African American males.

Maternal gut microbiome regulates immunity to RSV infection in offspring

Development of the immune system can be influenced by diverse extrinsic and intrinsic factors that influence the risk of disease. Severe early life respiratory syncytial virus (RSV) infection is associated with persistent immune alterations. Previously, our group had shown that adult mice orally supplemented with Lactobacillus johnsonii exhibited decreased airway immunopathology following RSV infection. Here, we demonstrate that offspring of mice supplemented with L. johnsonii exhibit reduced airway mucus and Th2 cell–mediated response to RSV infection. Maternal supplementation resulted in a consistent gut microbiome in mothers and their offspring. Importantly, supplemented maternal plasma and breastmilk, and offspring plasma, exhibited decreased inflammatory metabolites. Cross-fostering studies showed that prenatal Lactobacillus exposure led to decreased Th2 cytokines and lung inflammation following RSV infection, while postnatal Lactobacillus exposure diminished goblet cell hypertrophy and mucus production in the lung in response to airway infection. These studies demonstrate that Lactobacillus modulation of the maternal microbiome and associated metabolic reprogramming enhance airway protection against RSV in neonates.

Pediatric asthma incidence rates in the United States from 1980 to 2017

BACKGROUND

Few studies have examined longitudinal asthma incidence rates (IRs) from a public health surveillance perspective.

OBJECTIVE

Our aim was to calculate descriptive asthma IRs in children over time with consideration for demographics and parental asthma history.

METHODS

Data from 9 US birth cohorts were pooled into 1 population covering the period from 1980 to 2017. The outcome was earliest parental report of a doctor diagnosis of asthma. IRs per 1,000 person-years were calculated.

RESULTS

The racial/ethnic backgrounds of the 6,283 children studied were as follows: 55% European American (EA), 25.5% African American (AA), 9.5% Mexican-Hispanic American (MA) and 8.5% Caribbean-Hispanic American (CA). The average follow-up was 10.4 years (SD = 8.5 years; median = 8.4 years), totaling 65,291 person-years, with 1789 asthma diagnoses yielding a crude IR of 27.5 per 1,000 person-years (95% CI = 26.3-28.8). Age-specific rates were highest among children aged 0 to 4 years, notably from 1995 to 1999, with a decline in EA and MA children in 2000 to 2004 followed by a decline in AA and CA children in 2010 to 2014. Parental asthma history was associated with statistically significantly increased rates. IRs were similar and higher in AA and CA children versus lower but similar in EA and MA children. The differential rates by sex from birth through adolescence principally resulted from a decline in rates among males but relatively stable rates among females.

CONCLUSIONS

US childhood asthma IRs varied dramatically by age, sex, parental asthma history, race/ethnicity, and calendar year. Higher rates in the 0- to 4-year-olds group, particularly among AA/CA males with a parental history of asthma, as well as changes in rates over time and by demographic factors, suggest that asthma is driven by complex interactions between genetic susceptibility and variation in time-dependent environmental and social factors.

Inducible expression quantitative trait locus analysis of the MUC5AC gene in asthma in urban populations of children

BACKGROUND

Mucus plugging can worsen asthma control, lead to reduced lung function and fatal exacerbations. MUC5AC is the secretory mucin implicated in mucus plugging, and MUC5AC gene expression has been associated with development of airway obstruction and asthma exacerbations in urban children with asthma. However, the genetic determinants of MUC5AC expression are not established.

OBJECTIVES

This study sought to assess single-nucleotide polymorphisms (SNPs) that influence MUC5AC expression and relate to pulmonary functions in childhood asthma.

METHODS

This study used RNA-sequencing data from upper airway samples and performed cis-expression quantitative trait loci (eQTL) and allele-specific expression analyses in 2 cohorts of predominantly Black and Hispanic urban children, a high asthma-risk birth cohort, and an exacerbation-prone asthma cohort. Inducible MUC5AC eQTLs were further investigated during incipient asthma exacerbations. Significant eQTLs SNPs were tested for associations with lung function measurements and their functional consequences were investigated in DNA regulatory databases.

RESULTS

Two independent groups of SNPs in the MUC5AC gene that were significantly associated with MUC5AC expression were identified. Moreover, these SNPs showed stronger eQTL associations with MUC5AC expression during asthma exacerbations, which is consistent with inducible expression. SNPs in 1 group also showed significant association with decreased pulmonary functions. These SNPs included multiple EGR1 transcription factor binding sites, suggesting a mechanism of effect.

CONCLUSIONS

These findings demonstrate the applicability of organ-specific RNA-sequencing data to determine genetic factors contributing to a key disease pathway. Specifically, they suggest important genetic variations that may underlie propensity to mucus plugging in asthma and could be important in targeted asthma phenotyping and disease management strategies.

Increased risk of asthma at age 10 years for children sensitized to multiple allergens

BACKGROUND

Childhood sensitization patterns have been previously found to be related to variable risk of early life allergic disease in several birth cohorts.

OBJECTIVE

To determine whether these risks persist into later childhood.

METHODS

In the birth cohort of the Wayne County Health, Environment, Allergy and Asthma Longitudinal Study, previous latent class analysis based on sensitization to 10 allergens found the following 4 early life sensitization patterns at age 2 years: "highly sensitized," "milk/egg dominated," "peanut and inhalant(s)," and "low to no sensitization." At an age 10 study-specific visit, children were evaluated by an allergist for current asthma and atopic dermatitis through a physical examination and interviews with the child and parent or guardian. Total and specific immunoglobulin E (IgE), spirometry, and methacholine challenge were also completed.

RESULTS

Compared with children sensitized to none or 1 allergen, children sensitized to 4 or more food and inhalant allergens at age 2 had the highest risk of current asthma (relative risk [RR], 4.42; 95% confidence interval [CI], 2.58-7.59; P < .001) and bronchial hyperresponsiveness (RR, 1.77; 95% CI, 1.29-2.42; P < .001). In addition, they had the highest levels of total IgE (geometric mean, 800 IU/mL; 95% CI, 416-1536) among the 4 groups. Risk of current atopic dermatitis did not depend on pattern of sensitization but remained increased for children with any sensitization (RR, 2.23; 95% CI, 1.40-3.55; P < .001). No differences in spirometry (forced expiratory volume in 1 second, forced expiratory flow between 25% and 75%, and forced expiratory volume in 1 second/forced vital capacity) were identified.

CONCLUSION

The previously reported importance of a specific pattern of sensitization in early life (sensitization to ≥4 inhalant and food allergens) continues to be associated with an increased risk of asthma, bronchial hyperresponsiveness, and high total IgE at age 10 years.

Infant Feeding Practices and Subsequent Dietary Patterns of School-Aged Children in a US Birth Cohort

BACKGROUND

Infant feeding practices are thought to shape food acceptance and preferences. However, few studies have evaluated whether these affect child diet later in life.

OBJECTIVE

The study objective was to examine the association between infant feeding practices and dietary patterns (DPs) in school-aged children.

DESIGN

A secondary analysis of data from a diverse prospective birth cohort with 10 years of follow-up (WHEALS [Wayne County Health Environment Allergy and Asthma Longitudinal Study]) was conducted.

PARTICIPANTS/SETTING

Children from the WHEALS (Detroit, MI, born 2003 through 2007) who completed a food screener at age 10 years were included (471 of 1,258 original participants).

MAIN OUTCOME MEASURES

The main outcome was DPs at age 10 years, identified using the Block Kids Food Screener.

STATISTICAL ANALYSIS PERFORMED

Latent class analysis was applied for DP identification. Breastfeeding and age at solid food introduction were associated with DPs using a 3-step approach for latent class modeling based on multinomial logistic regression models.

RESULTS

The following childhood DPs were identified: processed/energy-dense food (35%), variety plus high intake (41%), and healthy (24%). After weighting for loss to follow-up and covariate adjustment, compared with formula-fed children at 1 month, breastfed children had 0.41 times lower odds of the processed/energy-dense food DP vs the healthy DP (95% CI 0.14 to 1.25) and 0.53 times lower odds of the variety plus high intake DP (95% CI 0.17 to 1.61), neither of which were statistically significant. Results were similar, but more imprecise, for breastfeeding at 6 months. In addition, the association between age at solid food introduction and DP was nonsignificant, with each 1-month increase in age at solid food introduction associated with 0.81 times lower odds of the processed/energy-dense food DP relative to the healthy DP (95% CI 0.64 to 1.02).

CONCLUSIONS

A significant association between early life feeding practices and dietary patterns at school age was not detected. Large studies with follow-up beyond early childhood that can also adjust for the multitude of potential confounders associated with breastfeeding are needed.

Association between asthma symptom scores and perceived stress and trait anxiety in adolescents with asthma

Background: Emotional disorders, including depression and anxiety, are more prevalent in individuals with asthma than in the general population and are associated with poor asthma outcomes. Identification of patients with increased levels of stress and anxiety may be helpful when treating asthma and during asthma counseling. Objective: To further characterize the relationship between asthma symptoms and perceived stress and trait anxiety in an adolescent population. Methods: Adolescents (N = 335) ages 14-17 years were recruited to examine the effect of stress on health measures. They were included in the present analysis if they reported current asthma, defined as self-reported clinician-diagnosed asthma plus one or more episodes of asthma in the past year. Asthma symptoms were assessed on a 7-point scale by using a standardized questionnaire that targets nocturnal awakening due to asthma, symptoms on awakening, activity limitation, shortness of breath, time spent wheezing, and short-acting bronchodilator use. Stress was measured by using the Perceived Stress Scale (PSS), and trait anxiety was measured by using the State-Trait Anxiety Inventory. Linear regression was used to associate asthma symptoms with PSS and trait anxiety. Results: Thirty-eight adolescents (11.3%), with mean ± standard deviation age 16.7 ± 0.9 years, reported current asthma. Four of the six asthma symptom assessments had significant associations with PSS: symptoms on awakening (β = 4.82, p < 0.001), nocturnal awakening due to asthma (β = 4.47, p < 0.001), activity limitation (β = 2.78, p = 0.005), and shortness of breath (β = 1.73, p = 0.014). These associations remained significant after adjusting for gender, race, and the body mass index percentile. Trait anxiety had significant associations with nocturnal awakening (β = 9.28, p = 0.002) and symptoms on awakening (β = 8.74, p = 0.002). Associations remained significant after adjusting for gender, race, and body mass index percentile. Conclusion: Asthma symptom severity is associated with increased perceived stress and trait anxiety. Adolescents with asthma may represent a population that is particularly vulnerable to perceived stress and anxiety, which highlights the importance of considering these factors in asthma counseling.

Racial disparities in allergic outcomes persist to age 10 years in black and white children

BACKGROUND

Previous analyses in the WHEALS birth cohort demonstrated that black children are more likely to experience allergic outcomes than white children by age 2 years. The results could not be explained by a host of variables.

OBJECTIVE

Assess whether racial disparities persisted to age 10 years and determine whether any differences could be explained by a panel of variables related to early life exposures in WHEALS.

METHODS

At age 10 years, WHEALS children (n = 481) completed skin prick testing, spirometry and methacholine challenge, and a physician examination for eczema and asthma. Allergen-specific immunoglobulin Es (sIgE) and total IgE were measured. Inverse probability weighting with logistic and linear regression models was used to assess associations between race (black or white) and the outcomes.

RESULTS

Black children fared worse than white children with respect to each outcome. Black children were more likely to have eczema, asthma, sensitization (≥1 sIgE ≥ 0.35 IU/L) and at least 1 positive skin pick test; however, some variability was present in the magnitudes of association within subgroups defined by delivery mode, sex of the child, prenatal indoor dog exposure, and firstborn status. In some subgroups, black children were also more likely to have higher total IgE and worse pulmonary function test measures (PC 20 ≤ 25 mg/mL, % predicted forced vital capacity [FVC], forced expiratory volume in 1 second [FEV₁]/FVC, forced expiratory flow from 25% to 75% of vital capacity [FEF_25-75]). Confounding did not explain these differences.

CONCLUSION

Racial differences persisted in this cohort through age 10 years. Future studies should include potentially important, but rarely studied factors such as segregation and structural racism, because these factors could explain the observed racial differences.

The Children's Respiratory and Environmental Workgroup (CREW) birth cohort consortium: design, methods, and study population

BACKGROUND

Single birth cohort studies have been the basis for many discoveries about early life risk factors for childhood asthma but are limited in scope by sample size and characteristics of the local environment and population. The Children's Respiratory and Environmental Workgroup (CREW) was established to integrate multiple established asthma birth cohorts and to investigate asthma phenotypes and associated causal pathways (endotypes), focusing on how they are influenced by interactions between genetics, lifestyle, and environmental exposures during the prenatal period and early childhood.

METHODS AND RESULTS

CREW is funded by the NIH Environmental influences on Child Health Outcomes (ECHO) program, and consists of 12 individual cohorts and three additional scientific centers. The CREW study population is diverse in terms of race, ethnicity, geographical distribution, and year of recruitment. We hypothesize that there are phenotypes in childhood asthma that differ based on clinical characteristics and underlying molecular mechanisms. Furthermore, we propose that asthma endotypes and their defining biomarkers can be identified based on personal and early life environmental risk factors. CREW has three phases: 1) to pool and harmonize existing data from each cohort, 2) to collect new data using standardized procedures, and 3) to enroll new families during the prenatal period to supplement and enrich extant data and enable unified systems approaches for identifying asthma phenotypes and endotypes.

CONCLUSIONS

The overall goal of CREW program is to develop a better understanding of how early life environmental exposures and host factors interact to promote the development of specific asthma endotypes.

Impact of Reported β-Lactam Allergy on Management of Methicillin-Sensitive Staphylococcus aureus Bloodstream Infections

BACKGROUND

Antistaphylococcal β-lactams antibiotics are the preferred treatment for methicillin-sensitive Staphylococcus aureus (MSSA) infections. Patient-reported β-lactam allergies may complicate antibiotic decision-making and delay optimal therapy, with potential implications on patient outcomes.

OBJECTIVE

To determine the impact of reported β-lactam allergies on the receipt of optimal therapy and outcomes for MSSA bloodstream infections (BSI).

METHODS

Retrospective, matched cohort of MSSA BSI patients with and without a reported β-lactam allergy. The primary end point was receipt of optimal therapy, defined as an antistaphylococcal β-lactam.

RESULTS

Two hundred twelve patients were included: 53 with reported β-lactam allergy and 159 without β-lactam allergy. Commonly reported β-lactam allergies were 26 (49%) immune-mediated reaction and 8 (15%) intolerance, with 19 (36%) having no documented reaction. Optimal antibiotics were given to 135 patients without a β-lactam allergy and 37 patients with a reported β-lactam allergy (85% vs 70%, P = .015). Among reported β-lactam allergy patients, those without a documented reaction were less likely to receive optimal therapy (47% vs 79%, P = .042). Reported β-lactam allergy was not associated with clinical response (P = .61) or MSSA-related mortality (P = .83). When adjusting for immunosuppression, variables independently associated with optimal therapy were β-lactam allergy (adjusted odds ratio [adjOR], 0.3; 95% confidence interval [CI], 0.1-0.6) and infectious diseases consultation (adjOR, 6.1; 95%CI, 2.7-13.9). Optimal antibiotic use was associated with decreased all-cause 90-day mortality (adjOR, 0.23; 95%CI, 0.09-0.54).

CONCLUSIONS

Patients with reported β-lactam allergies, particularly those without a documented reaction, were less likely to receive optimal antibiotics for MSSA BSI. Patient outcomes may be improved with enhanced quality of allergy history and routine infectious disease consultation.

Transcriptome networks identify mechanisms of viral and nonviral asthma exacerbations in children

Respiratory infections are common precursors to asthma exacerbations in children, but molecular immune responses that determine whether and how an infection causes an exacerbation are poorly understood. By using systems-scale network analysis, we identify repertoires of cellular transcriptional pathways that lead to and underlie distinct patterns of asthma exacerbation. Specifically, in both virus-associated and nonviral exacerbations, we demonstrate a set of core exacerbation modules, among which epithelial-associated SMAD3 signaling is upregulated and lymphocyte response pathways are downregulated early in exacerbation, followed by later upregulation of effector pathways including epidermal growth factor receptor signaling, extracellular matrix production, mucus hypersecretion, and eosinophil activation. We show an additional set of multiple inflammatory cell pathways involved in virus-associated exacerbations, in contrast to squamous cell pathways associated with nonviral exacerbations. Our work introduces an in vivo molecular platform to investigate, in a clinical setting, both the mechanisms of disease pathogenesis and therapeutic targets to modify exacerbations.

A computerized decision support tool to implement asthma guidelines for children and adolescents

BACKGROUND

Multicenter randomized controlled trials (RCTs) for asthma management that incorporate usual-care regimens could benefit from standardized application of evidence-based guidelines.

OBJECTIVE

We sought to evaluate performance of a computerized decision support tool, the Asthma Control Evaluation and Treatment (ACET) Program, to standardize usual-care regimens for asthma management in RCTs.

METHODS

Children and adolescents with persistent uncontrolled asthma living in urban census tracts were recruited into 3 multicenter RCTs (each with a usual-care arm) between 2004 and 2014. A computerized decision support tool scored asthma control and assigned an appropriate treatment step based on published guidelines. Control-level determinants (symptoms, rescue medication use, pulmonary function measure, and adherence estimates) were collected at visits and entered into the ACET Program. Changes in control levels and treatment steps were examined during the trials.

RESULTS

At screening, more than half of the participants were rated as having symptoms that were not controlled or poorly controlled. The proportion of participants who gained good control between screening and randomization increased significantly in all 3 trials. Between 51% and 70% had symptoms that were well controlled by randomization. The proportion of well-controlled participants remained constant or improved slightly from randomization until the last posttreatment visit. Nighttime symptoms were the most common control-level determinant; there were few (<1%) instances of complete overlap of factors. FEV₁ was the driver of control-level assignment in 30% of determinations.

CONCLUSION

The ACET Program decision support tool facilitated standardized asthma assessment and treatment in multicenter RCTs and was associated with attaining and maintaining good asthma control in most participants.

Obstruction phenotype as a predictor of asthma severity and instability in children

BACKGROUND

Small-airways instability resulting in premature airway closure has been recognized as a risk for asthma severity and poor control. Although spirometry has limited sensitivity for detecting small-airways dysfunction, a focus on the air-trapping component of obstruction might identify a risk factor for asthma instability.

OBJECTIVE

We sought to use spirometric measurements to identify patterns of airway obstruction in children and define obstruction phenotypes that relate to asthma instability.

METHODS

Prebronchodilation and postbronchodilation spirometric data were obtained from 560 children in the Asthma Phenotypes in the Inner City study. An air-trapping obstruction phenotype (A Trpg) was defined as a forced vital capacity (FVC) z score of less than -1.64 or an increase in FVC of 10% of predicted value or greater with bronchodilation. The airflow limitation phenotype (A Limit) had an FEV1/FVC z score of less than -1.64 but not A Trpg. The no airflow limitation or air-trapping criteria (None) phenotype had neither A Trpg nor A Limit. The 3 obstruction phenotypes were assessed as predictors of number of exacerbations, asthma severity, and airway lability.

RESULTS

Patients with the A Trpg phenotype (14% of the cohort) had more exacerbations during the 12-month study compared with those with the A Limit (P < .03) and None (P < .001) phenotypes. Patients with the A Trpg phenotype also had the highest Composite Asthma Severity Index score, the highest asthma treatment step, the greatest variability in FEV1 over time, and the greatest sensitivity to methacholine challenge.

CONCLUSIONS

A Trpg and A Limit patterns of obstruction, as defined by using routine spirometric measurements, can identify obstruction phenotypes that are indicators of risk for asthma severity and instability.

Asthma phenotypes in inner-city children

BACKGROUND

Children with asthma in low-income urban areas have high morbidity. Phenotypic analysis in these children is lacking, but may identify characteristics to inform successful tailored management approaches.

OBJECTIVE

We sought to identify distinct asthma phenotypes among inner-city children receiving guidelines-based management.

METHODS

Nine inner-city asthma consortium centers enrolled 717 children aged 6 to 17 years. Data were collected at baseline and prospectively every 2 months for 1 year. Participants' asthma and rhinitis were optimally managed by study physicians on the basis of guidelines. Cluster analysis using 50 baseline and 12 longitudinal variables was performed in 616 participants completing 4 or more follow-up visits.

RESULTS

Five clusters (designated A through E) were distinguished by indicators of asthma and rhinitis severity, pulmonary physiology, allergy (sensitization and total serum IgE), and allergic inflammation. In comparison to other clusters, cluster A was distinguished by lower allergy/inflammation, minimally symptomatic asthma and rhinitis, and normal pulmonary physiology. Cluster B had highly symptomatic asthma despite high step-level treatment, lower allergy and inflammation, and mildly altered pulmonary physiology. Cluster C had minimally symptomatic asthma and rhinitis, intermediate allergy and inflammation, and mildly impaired pulmonary physiology. Clusters D and E exhibited progressively higher asthma and rhinitis symptoms and allergy/inflammation. Cluster E had the most symptomatic asthma while receiving high step-level treatment and had the highest total serum IgE level (median, 733 kU/L), blood eosinophil count (median, 400 cells/mm³), and allergen sensitizations (15 of 22 tested).

CONCLUSIONS

Allergy distinguishes asthma phenotypes in urban children. Severe asthma often coclusters with highly allergic children. However, a symptomatic phenotype with little allergy or allergic inflammation was identified.

Pathways through which asthma risk factors contribute to asthma severity in inner-city children

BACKGROUND

Pathway analyses can be used to determine how host and environmental factors contribute to asthma severity.

OBJECTIVE

To investigate pathways explaining asthma severity in inner-city children.

METHODS

On the basis of medical evidence in the published literature, we developed a conceptual model to describe how 8 risk-factor domains (allergen sensitization, allergic inflammation, pulmonary physiology, stress, obesity, vitamin D, environmental tobacco smoke [ETS] exposure, and rhinitis severity) are linked to asthma severity. To estimate the relative magnitude and significance of hypothesized relationships among these domains and asthma severity, we applied a causal network analysis to test our model in an Inner-City Asthma Consortium study. Participants comprised 6- to 17-year-old children (n = 561) with asthma and rhinitis from 9 US inner cities who were evaluated every 2 months for 1 year. Asthma severity was measured by a longitudinal composite assessment of day and night symptoms, exacerbations, and controller usage.

RESULTS

Our conceptual model explained 53.4% of the variance in asthma severity. An allergy pathway (linking allergen sensitization, allergic inflammation, pulmonary physiology, and rhinitis severity domains to asthma severity) and the ETS exposure pathway (linking ETS exposure and pulmonary physiology domains to asthma severity) exerted significant effects on asthma severity. Among the domains, pulmonary physiology and rhinitis severity had the largest significant standardized total effects on asthma severity (-0.51 and 0.48, respectively), followed by ETS exposure (0.30) and allergic inflammation (0.22). Although vitamin D had modest but significant indirect effects on asthma severity, its total effect was insignificant (0.01).

CONCLUSIONS

The standardized effect sizes generated by a causal network analysis quantify the relative contributions of different domains and can be used to prioritize interventions to address asthma severity.

Distinguishing characteristics of difficult-to-control asthma in inner-city children and adolescents

BACKGROUND

Treatment levels required to control asthma vary greatly across a population with asthma. The factors that contribute to variability in treatment requirements of inner-city children have not been fully elucidated.

OBJECTIVE

We sought to identify the clinical characteristics that distinguish difficult-to-control asthma from easy-to-control asthma.

METHODS

Asthmatic children aged 6 to 17 years underwent baseline assessment and bimonthly guideline-based management visits over 1 year. Difficult-to-control and easy-to-control asthma were defined as daily therapy with 500 μg of fluticasone or greater with or without a long-acting β-agonist versus 100 μg or less assigned on at least 4 visits. Forty-four baseline variables were used to compare the 2 groups by using univariate analyses and to identify the most relevant features of difficult-to-control asthma by using a variable selection algorithm. Nonlinear seasonal variation in longitudinal measures (symptoms, pulmonary physiology, and exacerbations) was examined by using generalized additive mixed-effects models.

RESULTS

Among 619 recruited participants, 40.9% had difficult-to-control asthma, 37.5% had easy-to-control asthma, and 21.6% fell into neither group. At baseline, FEV₁ bronchodilator responsiveness was the most important characteristic distinguishing difficult-to-control asthma from easy-to-control asthma. Markers of rhinitis severity and atopy were among the other major discriminating features. Over time, difficult-to-control asthma was characterized by high exacerbation rates, particularly in spring and fall; greater daytime and nighttime symptoms, especially in fall and winter; and compromised pulmonary physiology despite ongoing high-dose controller therapy.

CONCLUSIONS

Despite good adherence, difficult-to-control asthma showed little improvement in symptoms, exacerbations, or pulmonary physiology over the year. In addition to pulmonary physiology measures, rhinitis severity and atopy were associated with high-dose asthma controller therapy requirement.

Does pet-keeping modify the association of delivery mode with offspring body size?

Caesarean-section (CS) delivery increases risk of childhood obesity, and is associated with a distinct early-life gut microbiome, which may contribute to obesity. Household pets may alter human gut microbiome composition. We examined if pet-keeping modified the association of CS with obesity at age 2 years in 639 Wayne County Health, Environment, Allergy and Asthma Longitudinal Study birth cohort participants. Pet-keeping was defined as having a dog or cat (indoors ≥1 h/day) at child age 2 years. We used logistic regression to test for an interaction between CS and pet-keeping with obesity (BMI ≥ 95th percentile) at age 2 years, adjusted for maternal obesity. A total of 328 (51.3 %) children were male; 367 (57.4 %) were African American; 228 (35.7 %) were born by CS; and 55 (8.6 %) were obese. After adjusting for maternal obesity, CS-born children had a non-significant (P = 0.25) but elevated 1.4 (95 % CI 0.8, 2.5) higher odds of obesity compared to those born vaginally. There was evidence of effect modification between current pet-keeping and delivery mode with obesity at age 2 years (interaction P = 0.054). Compared to children born vaginally without a pet currently in the home, children born via CS without a pet currently in the home had a statistically significant (P = 0.043) higher odds (odds ratio 2.00; 95 % CI 1.02, 3.93) of being obese at age 2 years. Pets modified the CS-BMI relationship; whether the underlying mechanism is through effects on environmental or gut microbiome requires specific investigation.

Exploring racial differences in IgE-mediated food allergy in the WHEALS birth cohort

BACKGROUND

Suspected food allergies are the cause of more than 200,000 visits to the emergency department annually. Racial differences in the prevalence of food allergy have also been reported, but the evidence is less conclusive. Researchers continue to struggle with the identification of food allergy for epidemiologic studies.

OBJECTIVE

To explore racial differences in IgE-mediated food allergy (IgE-FA) in a birth cohort.

METHODS

We used a panel of board-certified allergists to systematically identify IgE-FA to egg, milk, or peanut in a multiethnic birth cohort in which patient medical history, patient symptoms, and clinical data were available through 36 months of age.

RESULTS

Of the 590 infants analyzed, 52.9% were male and 65.8% African American. Sensitization (serum specific IgE >0.35 IU/mL) to the food allergens was significantly higher for African American children compared with non-African American children as has been previously reported. No statistically significant racial/ethnic differences in IgE-FA were observed; however, a higher proportion of African American children were designated as having peanut allergy, and the percentage of African American children with an IgE level greater than 95% predictive decision points for peanut was 1.7% vs 0.5% for non-African American children. With the use of logistic regression, race/ethnicity was not significantly associated with IgE-FA (adjusted odds ratio, 1.12; 95% confidence interval, 0.58-2.17; P = .75) but was associated with sensitization to more than 1 of the food allergens (adjusted odds ratio, 1.80; 95% confidence interval, 1.22-2.65; P = .003).

CONCLUSION

We did not observe an elevated risk of IgE-FA for African American children, although established differences in sensitization were observed. Racial/ethnic differences in sensitization must be taken into consideration when investigating disparities in asthma and allergy.

Race-specific Association of Caesarean-Section Delivery with Body Size at Age 2 Years

OBJECTIVE

African American children are at higher risk of obesity than White children and African American women are more likely to undergo caesarean-section (CS) delivery than White women. CS is associated with childhood obesity; however, little is known whether this relationship varies by race. We examined if the association of CS with obesity at age 2 years varied by race.

DESIGN

Longitudinal birth cohort.

SETTING

Birth cohort conducted in a health care system in metropolitan Detroit, Michigan with follow-up at age 2 years.

PARTICIPANTS

639 birth cohort participants; 367 children (57.4%) were born to African American mothers and 230 (36.0%) children were born via CS.

MAIN OUTCOME MEASURES

Obesity defined as body mass index ≥95th percentile at age 2 years.

RESULTS

Slightly more children of African American (n=37; 10.1%) than non-African American mothers (n=18; 6.6%) were obese (P=.12). There was evidence of effect modification between race and delivery mode with obesity at age 2 years (interaction P=.020). In children of African American mothers, CS compared to vaginal birth was associated with a significantly higher odds of obesity (aOR=2.35 (95% CI: 1.16, 4.77), P=.017). In contrast, delivery mode was not associated with obesity at age 2 years in children of non-African American mothers (aOR=.47 (95% CI: .13, 1.71), P=.25).

CONCLUSIONS

There is evidence for a race-specific effect of CS on obesity at age 2 years; potential underlying mechanisms may be racial differences in the developing gut microbiome or in epigenetic programming. Future research is needed to determine if this racial difference persists into later childhood.

Combined effects of prenatal medication use and delivery type are associated with eczema at age 2 years

BACKGROUND

Separately, prenatal antibiotics and Caesarian delivery have been found to be associated with increased risk of allergic diseases. It is not clear whether these factors may modify the effect of each other.

OBJECTIVE

To assess whether the associations between delivery types and eczema, sensitization and total IgE at age 2 years were modified by maternal use of prenatal medications.

METHODS

Prenatal charts of women enrolled in the WHEALS birth cohort were reviewed for delivery mode and medications prescribed and administered throughout their entire pregnancy, including systemic antibiotics and vaginally applied antifungal medications. The associations between the delivery mode and select medications and, eczema, sensitization (≥ 1 of 10 allergen-specific IgE ≥ 0.35 IU/mL) and total IgE at age 2 years were assessed.

RESULTS

There was a lower risk of eczema among vaginally vs. c-section born children (relative risk adjusted for race = aRR = 0.77, 95% CI 0.56, 1.05). Although not statistically significantly different, this association was stronger among the subset of children born vaginally to a mother who did not use systemic antibiotics or vaginal antifungal medications (aRR = 0.69, 95% CI 0.44, 1.08) compared to those born vaginally to mothers who used systemic antibiotics or vaginal antifungals (aRR = 0.81, 95% CI 0.57, 1.14). A protective association between vaginal birth and sensitization (aRR = 0.86, 95% CI 0.72, 1.03) was similar for those children born vaginally to a mother who did not (aRR = 0.87, 95% CI 0.69, 1.10) and who did (RR = 0.85, 95% CI 0.70, 1.04) use systemic antibiotics or vaginal antifungal medications. There were no associations with total IgE.

CONCLUSIONS

Children born vaginally had lower risk of eczema and sensitization compared with those born via c-section; however, the protective association with eczema may be slightly weakened when mothers took systemic antibiotics or vaginally applied medications during pregnancy.

Preseasonal treatment with either omalizumab or an inhaled corticosteroid boost to prevent fall asthma exacerbations

BACKGROUND

Short-term targeted treatment can potentially prevent fall asthma exacerbations while limiting therapy exposure.

OBJECTIVE

We sought to compare (1) omalizumab with placebo and (2) omalizumab with an inhaled corticosteroid (ICS) boost with regard to fall exacerbation rates when initiated 4 to 6 weeks before return to school.

METHODS

A 3-arm, randomized, double-blind, double placebo-controlled, multicenter clinical trial was conducted among inner-city asthmatic children aged 6 to 17 years with 1 or more recent exacerbations (clincaltrials.gov #NCT01430403). Guidelines-based therapy was continued over a 4- to 9-month run-in phase and a 4-month intervention phase. In a subset the effects of omalizumab on IFN-α responses to rhinovirus in PBMCs were examined.

RESULTS

Before the falls of 2012 and 2013, 727 children were enrolled, 513 were randomized, and 478 were analyzed. The fall exacerbation rate was significantly lower in the omalizumab versus placebo arms (11.3% vs 21.0%; odds ratio [OR], 0.48; 95% CI, 0.25-0.92), but there was no significant difference between omalizumab and ICS boost (8.4% vs 11.1%; OR, 0.73; 95% CI, 0.33-1.64). In a prespecified subgroup analysis, among participants with an exacerbation during the run-in phase, omalizumab was significantly more efficacious than both placebo (6.4% vs 36.3%; OR, 0.12; 95% CI, 0.02-0.64) and ICS boost (2.0% vs 27.8%; OR, 0.05; 95% CI, 0.002-0.98). Omalizumab improved IFN-α responses to rhinovirus, and within the omalizumab group, greater IFN-α increases were associated with fewer exacerbations (OR, 0.14; 95% CI, 0.01-0.88). Adverse events were rare and similar among arms.

CONCLUSIONS

Adding omalizumab before return to school to ongoing guidelines-based care among inner-city youth reduces fall asthma exacerbations, particularly among those with a recent exacerbation.

Association between vitamin D levels and allergy-related outcomes vary by race and other factors

BACKGROUND

Allergy-related studies that include biological measurements of vitamin D preceding well-measured outcomes are needed.

OBJECTIVE

We sought to examine the associations between early-life vitamin D levels and the development of allergy-related outcomes in the racially diverse Wayne County Health, Environment, Allergy, and Asthma Longitudinal Study birth cohort.

METHODS

25-Hydroxyvitamin D (25[OH]D) levels were measured in stored blood samples from pregnancy, cord blood, and age 2 years. Logistic regression models were used to calculate odds ratios (ORs) with 95% CIs for a 5 ng/mL increase in 25(OH)D levels for the following outcomes at age 2 years: eczema, skin prick tests (SPTs), increased allergen-specific IgE level (≥ 0.35 IU/mL), and doctor's diagnosis of asthma (3-6 years).

RESULTS

Prenatal 25(OH)D levels were inversely associated with eczema (OR, 0.85; 95% CI, 0.75-0.96). The association was stronger in white children (white children: OR, 0.79; 95% CI, 0.57-1.09; black children: OR, 0.96; 95% CI, 0.82-1.12), although this was not statistically significant. Cord blood 25(OH)D levels were inversely associated with having 1 or more positive SPT responses and aeroallergen sensitization. Both associations were statistically significant in white children (positive SPT response: OR, 0.50; 95% CI, 0.32-0.80; ≥ 1 aeroallergen sensitization: OR, 0.50; 95% CI, 0.28-0.92) in contrast with black children (positive SPT response: OR, 0.88; 95% CI, 0.68-1.14; ≥ 1 aeroallergen sensitization: OR, 0.85; 95% CI, 0.65-1.11). 25(OH)D levels measured concurrently with outcome assessment were inversely associated with aeroallergen sensitization (OR, 0.79; 95% CI, 0.66-0.96) only among black children (white children: OR, 1.21; 95% CI, 0.87-1.69).

CONCLUSIONS

Prenatal and cord blood 25(OH)D levels were associated with some allergy-related outcomes, with a general pattern indicating that children with higher 25(OH)D levels tend to have fewer allergy-related outcomes.