Socioeconomic status and childhood asthma in urban minority youths. The GALA II and SAGE II studies

Social Determinants of Health and Allergic Disease Prevalence Among Asian American Children

BACKGROUND

Although racial and ethnic disparities in allergic diseases have previously been observed, the relationship between social determinants of health (SDoH) and allergic disease prevalence among disaggregated Asian American (AsA) subgroups is poorly understood.

OBJECTIVE

To examine the association of SDoH with allergic disease prevalence among disaggregated AsA subgroups.

METHODS

Using the 2011-2018 National Health Interview Survey, we examined caregiver-reported race and ethnicity, SDoH, and allergic diseases. We compared survey-weighted allergic disease prevalence by AsA subgroup. Subgroup-stratified multivariable logistic regression accounting for age, sex, child/parent nativity, and survey year modeled the association between SDoH and allergic disease prevalence. We provide predicted probabilities of having each allergic disease based on exposure to each SDoH.

RESULTS

We examined data from 5042 non-Hispanic AsA children representing 3,264,768 AsA children. Approximately 25% of all AsA children reported at least one allergic disease, ranging from 20% of Asian Indian children to 30% of Filipino/a children. The number of unfavorable SDoH was lowest among Asian Indian and Chinese children (mean 0.7) and highest among "other Asian" children (mean 1.2). In stratified analyses, financial instability and inaccessible healthcare were associated with greater probability of allergic diseases among some, but not all AsA subgroups. Lower parent education level, food insecurity, and rent/other housing arrangement were associated with lower probability of allergic disease among some AsA children.

CONCLUSION

There was heterogeneity in the association of SDoH and allergic disease prevalence among AsA children. Further study of SDoH may inform modifiable environmental factors for allergic disease among AsA children.

Recommendations for Clinicians to Combat Environmental Disparities in Pediatric Asthma: A Review

TOPIC IMPORTANCE

Asthma is a common and complex lung disease in children, with disproportionally higher prevalence and related adverse outcomes among children in racial and ethnic minority groups and of lower socioeconomic position. Environmental factors, including unhealthy housing and school-based exposures, can contribute to increased asthma morbidity and widening disparities. This underscores a significant environmental justice issue and suggests the need for clinical interventions to reduce sources of environmental exposures and ultimately diminish the observed disparities in childhood asthma.

REVIEW FINDINGS

Unhealthy housing conditions, including secondhand tobacco smoke, allergen exposure, and indoor air pollution, can exacerbate asthma symptoms in children. Although unhealthy housing can occur anywhere, such situations most frequently occur in urban, low-income environments where renting is common. To reduce environmental triggers, clinicians can recommend smoking cessation, cleaning techniques to mitigate exposure, and even directly contacting landlords to address poor housing conditions. Children spend much of their time in schools, where this built environment is also a source of asthma triggers (eg, poor ventilation) and allergens (eg, mold and pests, chemicals). As such, a multidisciplinary approach is needed to adequately address the burden of childhood asthma to equitably reduce disparities to both harmful exposures and negative health outcomes.

SUMMARY

Racial, ethnic, and socioeconomic disparities exist in asthma morbidity in children, and such disparities are driven in part by environmental factors at the housing and school level. Clinicians can make evidence-based recommendations to drive effective exposure reduction strategies to mitigate asthma morbidity and reduce observed disparities.

Early-life exposure to residential greenness and risk of asthma in a U.S. bronchiolitis cohort

INTRODUCTION

Severe bronchiolitis (i.e., bronchiolitis requiring hospitalization) is linked to childhood asthma development. Despite a growing understanding of risk factors for developing post-bronchiolitis asthma, protective factors remain unclear. In this study, we aimed to investigate whether exposure to residential greenness between birth and bronchiolitis hospitalization is associated with asthma and atopic asthma development by age 6 years.

METHODS

We analyzed a US severe bronchiolitis cohort from hospitalization to age 6 years, investigating how the normalized difference vegetation index (NDVI) and chlorophyll index green (CI green), measured in small (100 m) and large (500 m) radiuses around homes, relate to asthma and atopic asthma by age 6 years. We also explored whether maternal antibiotic use, daycare attendance, and respiratory virus type during hospitalization act as effect modifiers.

RESULTS

The study cohort included 861 infants, with 239 (28%) developing asthma by age 6 years-152 atopic, 17 nonatopic, and 70 unclassified. Early life residential exposure to high NDVI and CI green levels was associated with lower odds of asthma (ORAdj for NDVI within a 100 m radius, 0.18; 95% CI, 0.05-0.78; and ORAdj for CI green levels within a 100 m radius, 0.53; 95% CI, 0.31-0.90). Associations also were significant for the development of atopic asthma (ORAdj 0.16; 95% CI, 0.03-0.96; and ORAdj 0.46; 95% CI, 0.25-0.92; respectively). Results were similar for the 500 m radius exposures. No effect modification was noted.

CONCLUSION

In a U.S. bronchiolitis cohort, exposure to residential greenness between birth and bronchiolitis hospitalization is linked to lower asthma and atopic asthma risk by age 6 years.

The frequency of asthma and its related factors: results of the enrolment phase of Tabari cohort study

INTRODUCTION

A large portion of the world's population has asthma. This study aimed to ascertain asthma prevalence and related factors in the Tabari cohort study (TCS).

METHODS

The TCS included 10,255 35-70-year-olds from urban and mountainous Sari (northern Iran) between June 2015 and November 2017. Education, occupation, domicile, socioeconomic position, history of psychiatric disorders, smoking (including hookah smoking), opium usage, and daily physical activity level were determined.

RESULTS

The final analysis included 9939 individuals. The asthma rate was 7.4%. Multiple factors increased asthma risk, according to statistical analysis. These factors included being female (OR, 1.337; 95% CI, 1.142-1.565), retired (OR, 1.553; 95% CI, 1.205-2.002), living in the city (OR, 1.268; 95% CI, 1.083-1.484), using opioids (OR, 1.689; 95% CI, 1.299-2.197), having lower socioeconomic status (SES) (OR, 0.723; 95% CI, 0.579-0.903), history of psychiatric disorders (OR, 2.313; 95% CI, 1.826-2.930), and aged 60-70 (OR, 2.325; 95% CI, 1.765-3.064), and BMI above 30 kg/m2 (OR, 1.499; 95% CI, 1.220-1.841). Several factors increased asthma probability in multivariate regression analysis. These factors include being female (OR = 1.389, p = 0.015), ages between 60 and 70 (OR = 2.034, p < 0.001), using opioids (OR = 1.940, p < 0.001), lower SES (OR = 0.738, p = 0.012), history of psychiatric disorders (OR = 2.035, p < 0.001), BMI above 30 kg/m2 (OR = 1.518, p < 0.001), and being a smoker (OR = 1.337, p = 0.056).

CONCLUSION

This study has identified that the prevalence of asthma in the Tabari cohort group is high. In addition, it was demonstrated that various factors are related to asthma.

Conceptualizing bias in EHR data: A case study in performance disparities by demographic subgroups for a pediatric obesity incidence classifier

Electronic Health Records (EHRs) are increasingly used to develop machine learning models in predictive medicine. There has been limited research on utilizing machine learning methods to predict childhood obesity and related disparities in classifier performance among vulnerable patient subpopulations. In this work, classification models are developed to recognize pediatric obesity using temporal condition patterns obtained from patient EHR data in a U.S. study population. We trained four machine learning algorithms (Logistic Regression, Random Forest, Gradient Boosted Trees, and Neural Networks) to classify cases and controls as obesity positive or negative, and optimized hyperparameter settings through a bootstrapping methodology. To assess the classifiers for bias, we studied model performance by population subgroups then used permutation analysis to identify the most predictive features for each model and the demographic characteristics of patients with these features. Mean AUC-ROC values were consistent across classifiers, ranging from 0.72-0.80. Some evidence of bias was identified, although this was through the models performing better for minority subgroups (African Americans and patients enrolled in Medicaid). Permutation analysis revealed that patients from vulnerable population subgroups were over-represented among patients with the most predictive diagnostic patterns. We hypothesize that our models performed better on under-represented groups because the features more strongly associated with obesity were more commonly observed among minority patients. These findings highlight the complex ways that bias may arise in machine learning models and can be incorporated into future research to develop a thorough analytical approach to identify and mitigate bias that may arise from features and within EHR datasets when developing more equitable models.

The burden of severe asthma in sub-Saharan Africa: Findings from the African Severe Asthma Project

Background

Severe asthma is associated with high morbidity, mortality, and health care utilization, but its burden in Africa is unknown.

Objective

We sought to determine the burden (prevalence, mortality, and activity and work impairment) of severe asthma in 3 countries in East Africa: Uganda, Kenya, and Ethiopia.

Methods

Using the American Thoracic Society/European Respiratory Society case definition of severe asthma, we analyzed for the prevalence of severe asthma (requiring Global Initiative for Asthma [GINA] steps 4-5 asthma medications for the previous year to achieve control) and severe refractory asthma (remains uncontrolled despite treatment with GINA steps 4-5 asthma medications) in a cohort of 1086 asthma patients who had been in care for 12 months and had received all GINA-recommended medications. Asthma control was assessed by the asthma control questionnaire (ACQ).

Results

Overall, the prevalence of severe asthma and severe refractory asthma was 25.6% (95% confidence interval [CI], 23.1-28.3) and 4.6% (95% CI, 3.5-6.0), respectively. Patients with severe asthma were (nonsevere vs severe vs severe refractory) older (39, 42, 45 years, P = .011), had high skin prick test reactivity (67.1%, 76.0%, 76.0%, P = .004), had lower forced expiratory volume in 1 second percentage (81%, 61%, 55.5%, P < .001), had lower quality of life score (129, 127 vs 121, P < .001), and had higher activity impairment (10%, 30%, 50%, P < .001). Factors independently associated with severe asthma were hypertension comorbidity; adjusted odds ratio 2.21 (1.10-4.47), P = .027, high bronchial hyperresponsiveness questionnaire score; adjusted odds ratio 2.16 (1.01-4.61), P = .047 and higher ACQ score at baseline 2.80 (1.55-5.08), P = .001.

Conclusion

The prevalence of severe asthma in Africa is high and is associated with high morbidity and poor quality of life.

Impact of climate change on paediatric respiratory health: pollutants and aeroallergens

Paediatric populations are particularly vulnerable to respiratory diseases caused and exacerbated by aeroallergens, pollutants and infectious agents. Worsening climate change is expected to increase the prevalence of pollutants and aeroallergens while amplifying disease severity and causing disproportionate effects in under-resourced areas. The purpose of this narrative review is to summarise the role of anthropogenic climate change in the literature examining the future impact of aeroallergens, pollutants and infectious agents on paediatric respiratory diseases with a focus on equitable disease mitigation. The aeroallergens selected for discussion include pollen, dust mites and mould as these are prevalent triggers of paediatric asthma worldwide. Human rhinovirus and respiratory syncytial virus are key viruses interacting with climate change and pollution and are primary causal agents of viral respiratory disease. Within this review, we present the propensity for aeroallergens, climate change and pollution to synergistically exacerbate paediatric respiratory disease and outline measures that can ameliorate the expected increase in morbidity and severity of disease through a health equity lens. We support shifting from fossil fuels to renewable energy worldwide, across sectors, as a primary means of reducing increases in morbidity.

Multi-omic approach associates blood methylome with bronchodilator drug response in pediatric asthma

BACKGROUND

Albuterol is the drug most widely used as asthma treatment among African Americans despite having a lower bronchodilator drug response (BDR) than other populations. Although BDR is affected by gene and environmental factors, the influence of DNA methylation is unknown.

OBJECTIVE

This study aimed to identify epigenetic markers in whole blood associated with BDR, study their functional consequences by multi-omic integration, and assess their clinical applicability in admixed populations with a high asthma burden.

METHODS

We studied 414 children and young adults (8-21 years old) with asthma in a discovery and replication design. We performed an epigenome-wide association study on 221 African Americans and replicated the results on 193 Latinos. Functional consequences were assessed by integrating epigenomics with genomics, transcriptomics, and environmental exposure data. Machine learning was used to develop a panel of epigenetic markers to classify treatment response.

RESULTS

We identified 5 differentially methylated regions and 2 CpGs genome-wide significantly associated with BDR in African Americans located in FGL2 (cg08241295, P = 6.8 × 10-9) and DNASE2 (cg15341340, P = 7.8 × 10-8), which were regulated by genetic variation and/or associated with gene expression of nearby genes (false discovery rate < 0.05). The CpG cg15341340 was replicated in Latinos (P = 3.5 × 10-3). Moreover, a panel of 70 CpGs showed good classification for those with response and nonresponse to albuterol therapy in African American and Latino children (area under the receiver operating characteristic curve for training, 0.99; for validation, 0.70-0.71). The DNA methylation model showed similar discrimination as clinical predictors (P > .05).

CONCLUSIONS

We report novel associations of epigenetic markers with BDR in pediatric asthma and demonstrate for the first time the applicability of pharmacoepigenetics in precision medicine of respiratory diseases.

Out-of-Hospital Presentation and Management of Asthma and Chronic Obstructive Pulmonary Disease Exacerbations in the United States: A Nationwide Retrospective Cohort Study

STUDY OBJECTIVE

To describe the demographic, clinical, and emergency medical service (EMS) response characteristics associated with EMS activations for asthma and chronic obstructive pulmonary disease (COPD) exacerbations in the US.

METHODS

Using a nationwide set of out-of-hospital patient care report data from 2018 to 2019, we analyzed 9-1-1 EMS activations where asthma/COPD exacerbation was indicated by symptom, impression, or treatment provided. We excluded patients with ages less than 2 years or unknown, nonemergency transports, and encounters with any indication of anaphylaxis. Demographic, clinical, and EMS response characteristics were described for pediatric and adult patients with asthma/COPD exacerbations.

RESULTS

A total of 1,336,988 asthma/COPD exacerbations were included, comprising 5% of qualifying 9-1-1 scene activations from 2018 to 2019. Most patients were adults (96%). Most adult patients were female (55%), whereas most pediatric patients were male (58%). Most activations occurred in urban settings (82%), particularly in pediatric patients (90%). Most asthma/COPD exacerbations were managed by advanced life support units (94%). Inhaled bronchodilators and systemic corticosteroid therapy were administered to 75% and 14% of all patients, respectively. Adults more often had oxygen saturation <92% (43% vs 20% of pediatric patients) and were more often treated with assisted ventilation (9% vs 1%).

CONCLUSION

In this large nationwide sample of 9-1-1 activations treated and transported by EMS, 5% were for asthma/COPD exacerbation. Future work should focus on evidence-based standardization of EMS protocols and practice for asthma/COPD exacerbations to improve the quality of EMS care.

Structural Racism and the Social Determinants of Health in Asthma

Asthma prevalence and morbidity are disproportionately higher among minoritized communities in the United States. Racial and ethnic disparities in asthma result from complex interactions across biological, environmental, and social factors. Asthma is considered a complex heterogeneous disease consisting of different phenotypes, some of which may be more common in individuals impacted by the downstream effects of structural racism and lack of access to the social determinants of health. Structural racism across generations has created and reinforced inequitable systems through policies and practices which are embedded in the economic, educational, health care, and justice systems (Bailey et al., N Engl J Med 384(8):768-773, 2021; Bailey et al., Lancet 389:1453-1463, 2017; Williams et al., Annu Rev Public Health 40:105-125, 2019). This manifests in an inequitable distribution of resources and the social determinants of health affecting an individual's physical and social environment (Bailey et al., Lancet 389:1453-1463, 2017; Thakur et al., Am J Respir Crit Care Med 202:943-949, 2020; Martinez et al., J Allergy Clin Immunol 148(5):1112-1120, 2021). In this chapter, we outline how inequity in housing, zoning laws, urban planning, education, employment, healthcare access, and healthcare delivery is linked to higher asthma prevalence and morbidity. We also describe the role that chronic physiologic stress has on asthma by enhancing neuroimmune and immunologic responses to environmental exposures. Interventions aimed at addressing the physical or social environment of an individual or community have been shown to improve asthma outcomes in patients at higher risk of severe disease.

Multi-omic association study identifies DNA methylation-mediated genotype and smoking exposure effects on lung function in children living in urban settings

Impaired lung function in early life is associated with the subsequent development of chronic respiratory disease. Most genetic associations with lung function have been identified in adults of European descent and therefore may not represent those most relevant to pediatric populations and populations of different ancestries. In this study, we performed genome-wide association analyses of lung function in a multiethnic cohort of children (n = 1,035) living in low-income urban neighborhoods. We identified one novel locus at the TDRD9 gene in chromosome 14q32.33 associated with percent predicted forced expiratory volume in one second (FEV1) (p = 2.4x10-9; βz = -0.31, 95% CI = -0.41- -0.21). Mendelian randomization and mediation analyses revealed that this genetic effect on FEV1 was partially mediated by DNA methylation levels at this locus in airway epithelial cells, which were also associated with environmental tobacco smoke exposure (p = 0.015). Promoter-enhancer interactions in airway epithelial cells revealed chromatin interaction loops between FEV1-associated variants in TDRD9 and the promoter region of the PPP1R13B gene, a stimulator of p53-mediated apoptosis. Expression of PPP1R13B in airway epithelial cells was significantly associated the FEV1 risk alleles (p = 1.3x10-5; β = 0.12, 95% CI = 0.06-0.17). These combined results highlight a potential novel mechanism for reduced lung function in urban youth resulting from both genetics and smoking exposure.

Association of County-degree Social Vulnerability with Chronic Respiratory Disease Mortality in the United States

Rationale: Chronic respiratory diseases, the third leading cause of death worldwide, have been associated with significant morbidity, mortality, and increased economic burden that make a profound impact on individuals and communities. However, limited research has delineated complex relationships between specific sociodemographic disparities and chronic respiratory disease outcomes among U.S. counties. Objectives: To assess the association of county-level sociodemographic vulnerabilities with chronic respiratory disease mortality in the United States. Methods: Chronic respiratory disease mortality data among U.S. counties for 2014-2018 was obtained from the CDC WONDER (Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research) database. The social vulnerability index (SVI), including subindices of socioeconomic status, household composition and disability, minority status and language, and housing type and transportation, is a composite, percentile-based measure developed by the CDC to evaluate county-level sociodemographic vulnerabilities to disasters. We examined county-level sociodemographic characteristics from the SVI and classified the percentile rank into quartiles, with a higher quartile indicating greater vulnerability. The associations between chronic respiratory disease mortality and overall SVI, its four subindices, and each county characteristic were analyzed by negative binomial regression. Results: From 2014 to 2018, the age-adjusted mortality per 1,000,000 population attributed to chronic lower respiratory disease was 406.4 (95% confidence interval [CI], 405.5-407.3); chronic obstructive pulmonary disease (COPD), 393.7 (392.8-394.6); asthma, 10.0 (9.9-10.2); interstitial lung disease (ILD), 50.5 (50.1-50.8); idiopathic pulmonary fibrosis (IPF), 37.0 (36.7-37.3); and sarcoidosis, 5.3 (5.2-5.4). Counties in the higher quartile of overall SVI were significantly associated with greater disease mortality (chronic lower respiratory disease, incidence rate ratios: fourth vs. first quartile, 1.43 [95% CI, 1.39-1.48]; COPD, 1.44 [1.39-1.49]; asthma, 2.06 [1.71-2.48]; ILD, 1.07 [1.02-1.13]; IPF, 1.14 [1.06-1.22]; sarcoidosis, 2.01 [1.44-2.81]). In addition, higher mortality was also found in counties in the higher quartile of each subindex and most sociodemographic characteristics. Conclusions: Chronic respiratory disease mortalities were significantly associated with county-level sociodemographic determinants as measured by the SVI in the United States. These findings suggested sociodemographic determinants may add a considerable barrier to establishing health equity. Multidegree public health strategies and clinical interventions addressing inequitable outcomes of chronic respiratory disease should be developed and targeted in areas with greater social vulnerability and disadvantage.

Duration of exposure to epidural anesthesia at delivery, DNA methylation in umbilical cord blood and their association with offspring asthma in Non-Hispanic Black women

Epidural anesthesia is an effective pain relief modality, widely used for labor analgesia. Childhood asthma is one of the commonest chronic medical illnesses in the USA which places a significant burden on the health-care system. We recently demonstrated a negative association between the duration of epidural anesthesia and the development of childhood asthma; however, the underlying molecular mechanisms still remain unclear. In this study of 127 mother-child pairs comprised of 75 Non-Hispanic Black (NHB) and 52 Non-Hispanic White (NHW) from the Newborn Epigenetic Study, we tested the hypothesis that umbilical cord blood DNA methylation mediates the association between the duration of exposure to epidural anesthesia at delivery and the development of childhood asthma and whether this differed by race/ethnicity. In the mother-child pairs of NHB ancestry, the duration of exposure to epidural anesthesia was associated with a marginally lower risk of asthma (odds ratio = 0.88, 95% confidence interval = 0.76-1.01) for each 1-h increase in exposure to epidural anesthesia. Of the 20 CpGs in the NHB population showing the strongest mediation effect, 50% demonstrated an average mediation proportion of 52%, with directional consistency of direct and indirect effects. These top 20 CpGs mapped to 21 genes enriched for pathways engaged in antigen processing, antigen presentation, protein ubiquitination and regulatory networks related to the Major Histocompatibility Complex (MHC) class I complex and Nuclear Factor Kappa-B (NFkB) complex. Our findings suggest that DNA methylation in immune-related pathways contributes to the effects of the duration of exposure to epidural anesthesia on childhood asthma risk in NHB offspring.

Characterizing clinical pediatric obesity subtypes using electronic health record data

In this work, we present a study of electronic health record (EHR) data that aims to identify pediatric obesity clinical subtypes. Specifically, we examine whether certain temporal condition patterns associated with childhood obesity incidence tend to cluster together to characterize subtypes of clinically similar patients. In a previous study, the sequence mining algorithm, SPADE was implemented on EHR data from a large retrospective cohort (n = 49 594 patients) to identify common condition trajectories surrounding pediatric obesity incidence. In this study, we used Latent Class Analysis (LCA) to identify potential subtypes formed by these temporal condition patterns. The demographic characteristics of patients in each subtype are also examined. An LCA model with 8 classes was developed that identified clinically similar patient subtypes. Patients in Class 1 had a high prevalence of respiratory and sleep disorders, patients in Class 2 had high rates of inflammatory skin conditions, patients in Class 3 had a high prevalence of seizure disorders, and patients in Class 4 had a high prevalence of Asthma. Patients in Class 5 lacked a clear characteristic morbidity pattern, and patients in Classes 6, 7, and 8 had a high prevalence of gastrointestinal issues, neurodevelopmental disorders, and physical symptoms respectively. Subjects generally had high membership probability for a single class (>70%), suggesting shared clinical characterization within the individual groups. We identified patient subtypes with temporal condition patterns that are significantly more common among obese pediatric patients using a Latent Class Analysis approach. Our findings may be used to characterize the prevalence of common conditions among newly obese pediatric patients and to identify pediatric obesity subtypes. The identified subtypes align with prior knowledge on comorbidities associated with childhood obesity, including gastro-intestinal, dermatologic, developmental, and sleep disorders, as well as asthma.

Parental Education Moderates the Relation between Physical Activity, Dietary Patterns and Atopic Diseases in Adolescents

Background: Atopic diseases, particularly asthma, eczema, and rhinitis, are among the most common chronic diseases in childhood, with several factors implicated in their pathogenesis. Our study examined the role of parental education in the association between diet, physical activity, and atopy in adolescents. Methods: 1934 adolescents (47.5% boys) aged 13−14 years old reported information about their diet and physical activity and their parents reported their highest educational level. The moderating role of parental education level (primary/secondary vs. tertiary) in the relation between lifestyle patterns and atopic diseases was examined with logistic regression analyses. Results: High consumption of dairy products was inversely associated to adolescents’ asthma and rhinitis symptoms overall, but this relation was almost 50% stronger for the adolescents with high parental education level background. The same pattern of reduction of the odds was noticed also regarding the association among the high intake of fruits, vegetables, pulses, with all three atopic diseases and the adherence to a physically active lifestyle only with current asthma and eczema (all p < 0.05). Conclusion: Adolescents who are physically active and consume a higher intake of fruits, vegetables, and pulses and a lower intake of fast-food and sweets, and their parents/guardians having higher education, are less likely to have any current symptoms of asthma, eczema, and rhinitis than the ones who have low educated parents.

Asthma in the Americas: An Update: A Joint Perspective from the Brazilian Thoracic Society, Canadian Thoracic Society, Latin American Thoracic Society, and American Thoracic Society

Asthma affects a large number of people living in the Americas, a vast and diverse geographic region comprising 35 nations in the Caribbean and North, Central, and South America. The marked variability in the prevalence, morbidity, and mortality from asthma across and within nations in the Americas offers a unique opportunity to improve our understanding of the risk factors and management of asthma phenotypes and endotypes in children and adults. Moreover, a better assessment of the causes and treatment of asthma in less economically developed regions in the Americas would help diagnose and treat individuals migrating from those areas to Canada and the United States. In this focused review, we first assess the epidemiology of asthma, review known and potential risk factors, and examine commonalities and differences in asthma management across the Americas. We then discuss future directions in research and health policies to improve the prevention, diagnosis, and management of pediatric and adult asthma in the Americas, including standardized and periodic assessment of asthma burden across the region; large-scale longitudinal studies including omics and comprehensive environmental data on racially and ethnically diverse populations; and dissemination and implementation of guidelines for asthma management across the spectrum of disease severity. New initiatives should recognize differences in socioeconomic development and health care systems across the region while paying particular attention to novel or more impactful risk factors for asthma in the Americas, including indoor pollutants such as biomass fuel, tobacco use, infectious agents and the microbiome, and psychosocial stressor and chronic stress.

Parental education moderates the association between indoor moisture environment and asthma in adolescents: the Greek Global Asthma Network (GAN) cross-sectional study

Objective

Asthma is a major contributor to childhood morbidity. Several environmental and socioeconomic status (SES) factors have been implicated in its etiopathogeneses such as indoor moisture and parental education level. Our study examined the association between exposure to indoor dampness and/or mould (IDM) with adolescent asthma and how parental education could modify or mediate this relationship.

Method

A total of 1934 adolescents (boys: 47.5%, mean age (standard variation): 12.7(0.6) years) and their parents were voluntarily enrolled and completed a validated questionnaire on adolescents’ asthma status, parental educational level, and adolescents’ indoor exposure to IDM during three different lifetime periods, i.e., pregnancy, the first year of life and the current time.

Results

There was a significant modification effect of parental education only for the current exposure; higher parental education lowered almost 50% the odds of IDM and asthma (adjusted odds ratio (aOR): 1.96, 95% Confidence Intervals (CI): (1.05–3.68) and aOR:1.55, 95% CI (1.04–2.32), for primary/secondary and tertiary parental education, respectively).

Conclusion

Adolescents whose parents had a higher education level had lesser odds to have asthma, even if they were exposed to a moisture home environment. This could be attributed to the increased knowledge about asthma risk factors and the improved measures for the amelioration of moisture-home environment that highly educated parents are more likely to take. Further research is needed in order to elucidate the interweaved role of family SES in the aforementioned relation.

Nasal airway transcriptome-wide association study of asthma reveals genetically driven mucus pathobiology

To identify genetic determinants of airway dysfunction, we performed a transcriptome-wide association study for asthma by combining RNA-seq data from the nasal airway epithelium of 681 children, with UK Biobank genetic association data. Our airway analysis identified 95 asthma genes, 58 of which were not identified by transcriptome-wide association analyses using other asthma-relevant tissues. Among these genes were MUC5AC, an airway mucin, and FOXA3, a transcriptional driver of mucus metaplasia. Muco-ciliary epithelial cultures from genotyped donors revealed that the MUC5AC risk variant increases MUC5AC protein secretion and mucus secretory cell frequency. Airway transcriptome-wide association analyses for mucus production and chronic cough also identified MUC5AC. These cis-expression variants were associated with trans effects on expression; the MUC5AC variant was associated with upregulation of non-inflammatory mucus secretory network genes, while the FOXA3 variant was associated with upregulation of type-2 inflammation-induced mucus-metaplasia pathway genes. Our results reveal genetic mechanisms of airway mucus pathobiology.

Bullying and lifetime asthma among children and adolescents in the United States

PURPOSE

To examine the association of experiencing bullying within the past year with the prevalence of lifetime childhood asthma in US children and adolescents; and whether this associations vary with sex of the child and select socioeconomic indicators.

METHODS

We performed secondary analysis of data from the 2018 National Survey of Children's Health participants aged 6 to 17 years (n=19,766). We used log-binomial regression to examine the association between bullying and lifetime childhood asthma before and after controlling for select covariates. We also tested interactions of bullying with sex and select socioeconomic indicators.

RESULTS

Children who experience bullying have a significantly increased probability of having asthma in adjusted analyses. The probability of childhood asthma increased with the frequency of bullying with PRs starting at 1.28 (95%CI:1.06, 1.55) for children bullied 1-2 times per year to 1.59 (95%:1.22, 2.09) for those being bullied at least 4 times per month. This association did not differ with sex of the child and select socioeconomic indicators.

CONCLUSION

We found that children who experienced bullying had a greater probability of having asthma relative to those who never experienced bullying. These finding highlight the impact of psychosocial stressors on asthma as a nontraditional trigger in children with asthma.

Maternal and early childhood factors associated with asthma and obesity in children aged 6 to 7 years: a case control study

Objective

To determine the maternal and early childhood factors associated with asthma and obesity in children aged 6 to 7 years.

Methods

A case-control study conducted with children aged 6 to 7 years. Applications with questions about asthma symptoms in the last 12 months, maternal and childhood data in the first 2 years of life, and anthropometric data were collected. Children who presented asthma symptoms were considered as cases and those without asthma symptoms were considered as controls, later divided into two subgroups that were eutrophic or overweight/obesity. Logistic regression was performed to estimate the association between asthma symptoms (adequate weight and overweight/obesity) and gestational and personal factors, calculating odds ratio and 95% confidence interval (95%CI). Values of p<0.05 were considered significant.

Results

Two hundred and one children were evaluated, 25.4% had asthma symptoms, 37.2% of them were overweight/obesity. Waist circumference, triceps skinfold, and body mass index were higher in the group with overweight/obesity asthma symptoms compared to no asthma symptoms (p<0.05). Factors significantly associated with asthma and overweight/obesity symptoms included: the maternal history of asthma (odds ratio of 3.73; 95%CI: 1.10-12.6) and hypertension during pregnancy (odds ratio of 3.29; 95%CI: 1.08-9.94).

Conclusion

Maternal history of asthma and hypertension during pregnancy increased the chances of children, at 6 and 7 years of age, having symptoms of asthma and obesity.

Interaction of maternal asthma history and plasma folate levels on child asthma risk in the Boston Birth Cohort

BACKGROUND

Previous studies on maternal folate status during pregnancy and child asthma risk yielded mixed results, and few considered maternal asthma history, a known risk factor of childhood asthma. This study examined whether the role of maternal folate in childhood asthma differs by maternal asthma history and whether there is an interaction between the two factors.

METHODS

This study included 1948 mother-child dyads from the Boston Birth Cohort. Childhood asthma was defined based on physician diagnosis documented in electronic medical records, and maternal asthma was based on standard questionnaire interview. Maternal plasma folate level within a few days of delivery was measured by chemiluminescent immunoassay. Logistic regression models were applied to examine individual and joint associations of maternal asthma history and plasma folate level with childhood asthma, adjusting for other covariables.

RESULTS

When stratified by maternal asthma history, an L-shaped relationship between maternal folate level and child asthma was observed in children born to mothers with asthma history (p_interaction  = 0.03). The highest risk was found in children having maternal asthma history and low maternal folate level (odds ratio = 5.93; 95% confidence interval: 2.86-12.3) compared with children without maternal asthma history and with sufficient maternal folate levels. Sensitivity analyses using different definitions of asthma and stratified by major covariables yielded similar findings.

CONCLUSION

In this US prospective high-risk birth cohort, maternal asthma history and low folate level interactively increased the risk of child asthma. If further confirmed, optimizing maternal folate levels during pregnancy may mitigate child asthma risk in the setting of maternal asthma history.

Structural racism and its pathways to asthma and atopic dermatitis

Black, Latinx, and Indigenous people in the United States experience a disproportionate burden of asthma and atopic dermatitis. The study of these disease disparities has focused on proximal socioenvironmental exposures and on the biomechanistic (including genetic) differences between racial and ethnic groups. Although biomedical research in allergy and immunology stands to benefit from the inclusion of diverse study populations, the narrow focus on biologic mechanisms disregards the complexity of interactions across biologic and structural factors, including the effects of structural racism. Structural racism is the totality of ways in which society fosters discrimination by creating and reinforcing inequitable systems through intentional policies and practices sanctioned by government and institutions. It is embedded across multiple levels, including the economic, educational, health care, and judicial systems, which are manifested in inequity in the physical and social environment. In this review, we present a conceptual framework and pull from the literature to demonstrate how structural racism is a root cause of atopic disease disparities by way of residential segregation, socioeconomic position, and mass incarceration, which may lead to aberrations in the innate and adaptive immune response and the augmentation of physiologic stress responses, contributing to a disproportionate disease burden for racial and ethnic populations.

Lymph node-resident dendritic cells drive TH2 cell development involving MARCH1

Type 2 T helper (TH2) cells are protective against parasitic worm infections but also aggravate allergic inflammation. Although the role of dendritic cells (DCs) in TH2 cell differentiation is well established, the underlying mechanisms are largely unknown. Here, we show that DC induction of TH2 cells depends on membrane-associated RING-CH-1 (MARCH1) ubiquitin ligase. The pro-TH2 effect of MARCH1 relied on lymph node (LN)–resident DCs, which triggered T cell receptor (TCR) signaling and induced GATA-3 expression from naïve CD4+ T cells independent of tissue-driven migratory DCs. Mice with mutations in the ubiquitin acceptor sites of MHCII and CD86, the two substrates of MARCH1, failed to develop TH2 cells. These findings suggest that TH2 cell development depends on ubiquitin-mediated clearance of antigen-presenting and costimulatory molecules by LN-resident DCs and consequent control of TCR signaling.

Associations between the spatiotemporal distribution of Kawasaki disease and environmental factors: evidence supporting a multifactorial etiologic model

The etiology of Kawasaki Disease (KD), the most common cause of acquired heart disease in children in developed countries, remains elusive, but could be multifactorial in nature as suggested by the numerous environmental and infectious exposures that have previously been linked to its epidemiology. There is still a lack of a comprehensive model describing these complex associations. We present a Bayesian disease model that provides insight in the spatiotemporal distribution of KD in Canada from 2004 to 2017. The disease model including environmental factors had improved Watanabe-Akaike information criterion (WAIC) compared to the base model which included only spatiotemporal and demographic effects and had excellent performance in recapitulating the spatiotemporal distribution of KD in Canada (98% and 86% spatial and temporal correlations, respectively). The model suggests an association between the distribution of KD and population composition, weather-related factors, aeroallergen exposure, pollution, atmospheric concentration of spores and algae, and the incidence of healthcare encounters for bacterial pneumonia or viral intestinal infections. This model could be the basis of a hypothetical data-driven framework for the spatiotemporal distribution of KD. It also generates novel hypotheses about the etiology of KD, and provides a basis for the future development of a predictive and surveillance model.

Defining pediatric asthma: phenotypes to endotypes and beyond

Asthma is the most common chronic pediatric lung disease that has traditionally been defined as a syndrome of airway inflammation characterized by clinical symptoms of cough and wheeze. Highlighting the complex and heterogeneous nature of asthma, this review summarizes recent advances in asthma classification that are based on pathobiology, and thereby directly addresses limitations of existent definitions of asthma. By reviewing and contrasting clinical and mechanistic features of adult and childhood asthma, the review summarizes key biomarkers that distinguish childhood asthma subtypes. While atopy and its severity are important features of childhood asthma, there is evidence to support the existence of a childhood asthma endotype distinct from the atopic endotype. Although biomarkers of non-atopic asthma are an area of future research, we summarize a clinical approach that includes existing measures of airway-specific and systemic measures of atopy, co-existing morbidities, and disease severity and control, in the definition of childhood asthma, to empower health care providers to better characterize asthma disease burden in children. Identification of biomarkers of non-atopic asthma and the contribution of genetics and epigenetics to pediatric asthma burden remains a research need, which can potentially allow delivery of precision medicine to pediatric asthma. IMPACT: This review highlights asthma as a complex and heterogeneous disease and discusses recent advances in the understanding of the pathobiology of asthma to demonstrate the need for a more nuanced definitions of asthma. We review current knowledge of asthma phenotypes and endotypes and put forth an approach to endotyping asthma that may be useful for defining asthma for clinical care as well as for future research studies in the realm of personalized medicine for asthma.

Genetic ancestry differences in pediatric asthma readmission are mediated by socioenvironmental factors

BACKGROUND

Social and financial hardships, combined with disease managment and environmental factors explain approximately 80% of the observed disparity in asthma-related readmissions between Black and White children.

OBJECTIVE

We sought to determine whether asthma-related readmissions differed by degree of African ancestry and the extent to which such an association would also be explained by socioenvironmental risk factors.

METHODS

This study used data from a prospective cohort study of 695 Black and White children aged 1 to 16 years with an asthma-related admission. The primary outcome was a similar readmission within 12 months. Each subject's African ancestry was determined by single nucleotide polymorphisms on a continuous scale ranging from 0 to 1 (0 = no African ancestry; 1 = 100% African ancestry). We also assessed 37 social, environmental, and clinical variables that we clustered into 6 domains (for example, hardship, disease management). Survival and mediation analyses were conducted.

RESULTS

A total of 134 children (19.3%) were readmitted within 12 months. Higher African ancestry was associated with asthma readmission (odds ratio 1.11, 95% confidence interval 1.05-1.18 for every 10% increase in African ancestry) with adjustment for age and gender. The association between African ancestry and readmission was mediated by hardship (sβ = 3.42, P < .001) and disease management (sβ = 0.046, P = .001), accounting for >50% of African ancestry's effect on readmission. African ancestry was no longer significantly associated with readmission (sβ = 0.035, P = .388) after accounting for these mediators.

CONCLUSIONS

African ancestry was strongly associated with readmission, and the association was mediated by family hardship and disease management. These results are consistent with the notion that asthma-related racial disparities are driven by factors like structural racism and social adversity.

Integrative genomic analysis in African American children with asthma finds three novel loci associated with lung function

Bronchodilator (BD) drugs are commonly prescribed for treatment and management of obstructive lung function present with diseases such as asthma. Administration of BD medication can partially or fully restore lung function as measured by pulmonary function tests. The genetics of baseline lung function measures taken before BD medication have been extensively studied, and the genetics of the BD response itself have received some attention. However, few studies have focused on the genetics of post-BD lung function. To address this gap, we analyzed lung function phenotypes in 1103 subjects from the Study of African Americans, Asthma, Genes, and Environment, a pediatric asthma case-control cohort, using an integrative genomic analysis approach that combined genotype, locus-specific genetic ancestry, and functional annotation information. We integrated genome-wide association study (GWAS) results with an admixture mapping scan of three pulmonary function tests (forced expiratory volume in 1 s [FEV1 ], forced vital capacity [FVC], and FEV1 /FVC) taken before and after albuterol BD administration on the same subjects, yielding six traits. We identified 18 GWAS loci, and five additional loci from admixture mapping, spanning several known and novel lung function candidate genes. Most loci identified via admixture mapping exhibited wide variation in minor allele frequency across genotyped global populations. Functional fine-mapping revealed an enrichment of epigenetic annotations from peripheral blood mononuclear cells, fetal lung tissue, and lung fibroblasts. Our results point to three novel potential genetic drivers of pre- and post-BD lung function: ADAMTS1, RAD54B, and EGLN3.

Native American Ancestry and Air Pollution Interact to Impact Bronchodilator Response in Puerto Rican Children with Asthma

Objective

Asthma is the most common chronic disease in children. Short-acting bronchodilator medications are the most commonly prescribed asthma treatment worldwide, regardless of disease severity. Puerto Rican children display the highest asthma morbidity and mortality of any US population. Alarmingly, Puerto Rican children with asthma display poor bronchodilator drug response (BDR). Reduced BDR may explain, in part, the increased asthma morbidity and mortality observed in Puerto Rican children with asthma. Gene-environment interactions may explain a portion of the heritability of BDR. We aimed to identify gene-environment interactions associated with BDR in Puerto Rican children with asthma.

Setting

Genetic, environmental, and psycho-social data from the Genes-environments and Admixture in Latino Americans (GALA II) case-control study.

Participants

Our discovery dataset consisted of 658 Puerto Rican children with asthma; our replication dataset consisted of 514 Mexican American children with asthma.

Main Outcome Measures

We assessed the association of pairwise interaction models with BDR using ViSEN (Visualization of Statistical Epistasis Networks).

Results

We identified a non-linear interaction between Native American genetic ancestry and air pollution significantly associated with BDR in Puerto Rican children with asthma. This interaction was robust to adjustment for age and sex but was not significantly associated with BDR in our replication population.

Conclusions

Decreased Native American ancestry coupled with increased air pollution exposure was associated with increased BDR in Puerto Rican children with asthma. Our study acknowledges BDR's phenotypic complexity, and emphasizes the importance of integrating social, environmental, and biological data to further our understanding of complex disease.

Association of Affordable Care Act Implementation With Ambulance Utilization for Asthma Emergencies in New York City, 2008-2018

IMPORTANCE

Emergency medical services (EMS) are an essential component of the health care system, but the effect of insurance expansion on EMS call volume remains unclear.

OBJECTIVE

This study investigated the association between health insurance expansion and EMS dispatches for asthma, an ambulatory care-sensitive condition. We hypothesized that insurance expansion under the Patient Protection and Affordable Care Act (ACA) would be associated with decreased EMS dispatches for asthma emergencies.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study examined 14 865 267 ambulance calls dispatched within New York City from 2008 to 2018, including 217 303 calls for asthma-related emergencies, and used interrupted time series analysis to study the change in the annual incidence of EMS dispatches for asthma emergencies after implementation of the ACA. Multivariable linear regression examined the association between the uninsured rate and the incidence of asthma-related dispatches, controlling for population demographic characteristics and air quality index.

EXPOSURES

Implementation of ACA on January 1, 2014.

MAIN OUTCOMES AND MEASURES

Incidence of EMS dispatches for asthma emergencies per 100 000 population per year (ie, asthma EMS dispatch rate) as classified by the 911 call-taker.

RESULTS

In this study of 217 303 EMS dispatches for asthma-related emergencies, there was a decrease in the asthma EMS dispatch rate after implementation of the ACA, from a mean (SD) of 261 (24) dispatches per 100 000 population per year preintervention to 211 (47) postintervention (P = .047). This decrease in asthma EMS dispatch rate after ACA implementation was significant on interrupted time series analysis. Prior to 2014, the annual asthma EMS dispatch rate was increasing by 11.8 calls per 100 000 population per year (95% CI, 6.1 to 17.4). After ACA implementation, the asthma EMS dispatch rate decreased annually by 28.5 calls per 100 000 population per year (95% CI, -37.6 to -19.3), a significant change in slope from the preintervention period (P < .001). Multivariable linear regression, controlling for percentage of individuals younger than age 18 years, degree of racial/ethnic diversity, median household income, and air quality index, found that a 1% decrease in the citywide uninsured rate was associated with a decrease of 98.9 asthma dispatches per 100 000 population per year (95% CI, 5.72-192.10; P = .04).

CONCLUSIONS AND RELEVANCE

Insurance expansion within New York City under the ACA was associated with a significant reduction in the asthma EMS dispatch rate. Insurance expansion may be a viable method to reduce EMS utilization for ambulatory care-sensitive conditions such as asthma.

Type 2 and interferon inflammation regulate SARS-CoV-2 entry factor expression in the airway epithelium

Coronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2, an emerging virus that utilizes host proteins ACE2 and TMPRSS2 as entry factors. Understanding the factors affecting the pattern and levels of expression of these genes is important for deeper understanding of SARS-CoV-2 tropism and pathogenesis. Here we explore the role of genetics and co-expression networks in regulating these genes in the airway, through the analysis of nasal airway transcriptome data from 695 children. We identify expression quantitative trait loci for both ACE2 and TMPRSS2, that vary in frequency across world populations. We find TMPRSS2 is part of a mucus secretory network, highly upregulated by type 2 (T2) inflammation through the action of interleukin-13, and that the interferon response to respiratory viruses highly upregulates ACE2 expression. IL-13 and virus infection mediated effects on ACE2 expression were also observed at the protein level in the airway epithelium. Finally, we define airway responses to common coronavirus infections in children, finding that these infections generate host responses similar to other viral species, including upregulation of IL6 and ACE2. Our results reveal possible mechanisms influencing SARS-CoV-2 infectivity and COVID-19 clinical outcomes.

Quality of life in at-risk school-aged children with asthma

INTRODUCTION

Asthma is the most common chronic condition of childhood. Urban, minority children from families of lower socioeconomic status have disproportionately higher rates of asthma and worse outcomes. We investigated the association between the presence of asthma and asthma severity among American, urban, minority children and reported quality of life (QOL) of children and their families.

METHODS

We performed a prospective, cross-sectional study comparing QOL of urban, minority elementary school-age children with and without asthma. A convenience sample of children was enrolled from the pediatric emergency department (ED) and a specialized asthma clinic, at a large urban children's hospital. We measured child and parent QOL using the Pediatric Quality of Life Inventory Version 4 (PEDSQL4), and evaluated associations with asthma, parental educational attainment, and frequency of ED visits.

RESULTS

We enrolled 66 children, 76% were African American, and 61% were female. Overall child QOL was higher for those without asthma (p = 0.017, d = 0.59). Children with asthma also visited the ED almost twice as frequently (t [64] = -3.505, p < 0.001, d = 0.8), and parents of children with asthma reported a lower overall QOL (p = 0.04, d = 0.53) than those without asthma. Among children with asthma, a higher overall child QOL was associated with decreased asthma severity, more ED visits, and higher parental educational attainment.

CONCLUSIONS

Urban, minority elementary school-age children with asthma report a lower QOL than those children without asthma, and decreased asthma severity was associated with higher QOL.

Screening Social Determinants of Health in a Multidisciplinary Severe Asthma Clinical Program

Supplemental Digital Content is available in the text.

Asthma is the most common cause of chronic disease in children and has high healthcare utilization costs. Minority children living in poverty have a higher asthma burden. These health disparities are associated with the social determinants of health (SDH). A severe asthma clinic was implemented at Rady Children’s Hospital in San Diego to determine whether a multidisciplinary approach, including an asthma home visit addressing SDH, would lead to decreased healthcare utilization in terms of emergency department (ED) visits and hospitalizations.

Pediatric Asthma Health Care Utilization, Viral Testing, and Air Pollution Changes During the COVID-19 Pandemic

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic caused dramatic changes in daily routines and health care utilization and delivery patterns in the United States. Understanding the influence of these changes and associated public health interventions on asthma care is important to determine effects on patient outcomes and identify measures that will ensure optimal future health care delivery.

OBJECTIVE

We sought to identify changes in pediatric asthma-related health care utilization, respiratory viral testing, and air pollution during the COVID-19 pandemic.

METHODS

For the time period January 17 to May 17, 2015 to 2020, asthma-related encounters and weekly summaries of respiratory viral testing data were extracted from Children's Hospital of Philadelphia electronic health records, and pollution data for 4 criteria air pollutants were extracted from AirNow. Changes in encounter characteristics, viral testing patterns, and air pollution before and after Mar 17, 2020, the date public health interventions to limit viral transmission were enacted in Philadelphia, were assessed and compared with data from 2015 to 2019 as a historical reference.

RESULTS

After March 17, 2020, in-person asthma encounters decreased by 87% (outpatient) and 84% (emergency + inpatient). Video telemedicine, which was not previously available, became the most highly used asthma encounter modality (61% of all visits), and telephone encounters increased by 19%. Concurrently, asthma-related systemic steroid prescriptions and frequency of rhinovirus test positivity decreased, although air pollution levels did not substantially change, compared with historical trends.

CONCLUSIONS

The COVID-19 pandemic in Philadelphia was accompanied by changes in pediatric asthma health care delivery patterns, including reduced admissions and systemic steroid prescriptions. Reduced rhinovirus infections may have contributed to these patterns.

On the cross-population generalizability of gene expression prediction models

The genetic control of gene expression is a core component of human physiology. For the past several years, transcriptome-wide association studies have leveraged large datasets of linked genotype and RNA sequencing information to create a powerful gene-based test of association that has been used in dozens of studies. While numerous discoveries have been made, the populations in the training data are overwhelmingly of European descent, and little is known about the generalizability of these models to other populations. Here, we test for cross-population generalizability of gene expression prediction models using a dataset of African American individuals with RNA-Seq data in whole blood. We find that the default models trained in large datasets such as GTEx and DGN fare poorly in African Americans, with a notable reduction in prediction accuracy when compared to European Americans. We replicate these limitations in cross-population generalizability using the five populations in the GEUVADIS dataset. Via realistic simulations of both populations and gene expression, we show that accurate cross-population generalizability of transcriptome prediction only arises when eQTL architecture is substantially shared across populations. In contrast, models with non-identical eQTLs showed patterns similar to real-world data. Therefore, generating RNA-Seq data in diverse populations is a critical step towards multi-ethnic utility of gene expression prediction.

An epistatic interaction between pre-natal smoke exposure and socioeconomic status has a significant impact on bronchodilator drug response in African American youth with asthma

BACKGROUND

Asthma is one of the leading chronic illnesses among children in the United States. Asthma prevalence is higher among African Americans (11.2%) compared to European Americans (7.7%). Bronchodilator medications are part of the first-line therapy, and the rescue medication, for acute asthma symptoms. Bronchodilator drug response (BDR) varies substantially among different racial/ethnic groups. Asthma prevalence in African Americans is only 3.5% higher than that of European Americans, however, asthma mortality among African Americans is four times that of European Americans; variation in BDR may play an important role in explaining this health disparity. To improve our understanding of disparate health outcomes in complex phenotypes such as BDR, it is important to consider interactions between environmental and biological variables.

RESULTS

We evaluated the impact of pairwise and three-variable interactions between environmental, social, and biological variables on BDR in 233 African American youth with asthma using Visualization of Statistical Epistasis Networks (ViSEN). ViSEN is a non-parametric entropy-based approach able to quantify interaction effects using an information-theory metric known as Information Gain (IG). We performed analyses in the full dataset and in sex-stratified subsets. Our analyses identified several interaction models significantly, and suggestively, associated with BDR. The strongest interaction significantly associated with BDR was a pairwise interaction between pre-natal smoke exposure and socioeconomic status (full dataset IG: 2.78%, p = 0.001; female IG: 7.27%, p = 0.004)). Sex-stratified analyses yielded divergent results for females and males, indicating the presence of sex-specific effects.

CONCLUSIONS

Our study identified novel interaction effects significantly, and suggestively, associated with BDR in African American children with asthma. Notably, we found that all of the interactions identified by ViSEN were "pure" interaction effects, in that they were not the result of strong main effects on BDR, highlighting the complexity of the network of biological and environmental factors impacting this phenotype. Several associations uncovered by ViSEN would not have been detected using regression-based methods, thus emphasizing the importance of employing statistical methods optimized to detect both additive and non-additive interaction effects when studying complex phenotypes such as BDR. The information gained in this study increases our understanding and appreciation of the complex nature of the interactions between environmental and health-related factors that influence BDR and will be invaluable to biomedical researchers designing future studies.

Air pollution and children's respiratory health: a scoping review of socioeconomic status as an effect modifier

OBJECTIVES

Air pollution is a leading environmental risk, and socioeconomic status (SES) is postulated as an effect modifier, especially in children. There is a growing interest in exploring this modifier. The present manuscript reviews SES as an effect modifier in children's respiratory health.

METHODS

A search in the PubMed and SCOPUS databases was conducted in September 2017 to identify studies with the inclusion criteria of being centred on children, respiratory outcomes, air pollutants and SES measurement.

RESULTS

A total of 17 studies were included. Twelve used single SES variables, and the remaining studies included composite SES indices. Household income (9) and parental education (8) were frequently evaluated. The significance of the effect modifier was found in nine studies that demonstrated a higher risk for individuals living in a lower SES. Sources of heterogeneity included SES measurement, health outcomes and geographical aggregation.

CONCLUSIONS

The results suggest a higher modification in the effect of SES, generally indicating greater risk for children in lower SES. Children's characteristics need to be more carefully theorized and measured in this area, including the use of transdisciplinary approaches.

Estimated Prevalence of Asthma in US Children With Developmental Disabilities

IMPORTANCE

The prevalence of asthma in US children with various developmental disabilities and delays is unclear, including how estimates vary by ethnic group.

OBJECTIVE

To report asthma prevalence estimates by various disability categories and developmental delays in a diverse sample of the US pediatric population.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cross-sectional study encompassed a total of 71 811 families with children or adolescents aged 0 to 17 years (hereinafter referred to as children) who participated in the 2016 and 2017 National Survey of Children's Health. Data were collected from June 10, 2016, to February 10, 2017, for the 2016 survey and from August 10, 2017, to February 10, 2018, for the 2017 survey. Data were analyzed from September 20, 2019, to April 5, 2020.

EXPOSURES

Developmental disability, including attention-deficit/hyperactivity disorder, autism spectrum disorder, cerebral palsy, seizure, intellectual and/or learning disability, and vision, hearing, and/or speech delay. Delay was defined as not meeting growth milestones with unknown cause.

MAIN OUTCOMES AND MEASURES

Weighted asthma prevalence estimates and 95% CIs were generated for children with and without disabilities.

RESULTS

A total of 71 811 participants (mean [SE] age, 8.6 [0.1] years; 36 800 boys [51.1%; 95% CI, 50.2%-52.0%]; 50 219 non-Hispanic white [51.4%; 95% CI, 50.6%-52.3%]) were included in our final analytical sample, of whom 5687 (7.9%; 95% CI, 7.5%-8.4%) had asthma and 11 426 (15.3%; 95% CI, 14.7%-16.0%) had at least 1 disability. Overall asthma prevalence estimates were 10 percentage points higher in children with a disability (16.1%; 95% CI, 14.3%-17.8%) vs children without a disability (6.5%; 95% CI, 6.0%-6.9%). The odds of asthma were significantly higher in children with a disability (odds ratio [OR], 2.77; 95% CI, 2.39-3.21) or delay (OR, 2.22; 95% CI, 1.78-2.77) vs typically growing children. Adjusted models remained significant for all disability categories (overall adjusted OR, 2.21; 95% CI, 1.87-2.62). Subgroup analyses showed ethnic minorities had a higher prevalence of concurrent asthma and developmental disabilities vs non-Hispanic whites (19.8% [95% CI, 16.6%-23.0%] vs 12.6% [95% CI, 11.1%-14.0%]; P < .001).

CONCLUSIONS AND RELEVANCE

These results suggest that US children with various developmental disabilities or delay may have higher odds for developing asthma vs their typically developing peers. These findings support asthma screening in pediatric health care settings among patients with developmental disabilities and delays, particularly among those from ethnic minority backgrounds. In addition, very young children with asthma should be screened for disabilities and delays, because temporality cannot be determined by the current data source and analytical approach.

Differential asthma odds following respiratory infection in children from three minority populations

RATIONALE

Severe early-life respiratory illnesses, particularly those caused by respiratory syncytial virus (RSV) and human rhinovirus (HRV), are strongly associated with the development of asthma in children. Puerto Rican children in particular have a strikingly high asthma burden. However, prior studies of the potential associations between early-life respiratory illnesses and asthma in Puerto Rican and other minority populations have been limited.

OBJECTIVES

We sought to determine whether early-life respiratory illness was associated with asthma in Puerto Rican, Mexican American, and African American children.

METHODS

Using a logistic regression analysis, we examined the association between early-life respiratory illnesses (report of upper respiratory infection (URI), pneumonia, bronchitis, and bronchiolitis/RSV) within the first two years of life and physician-diagnosed asthma after the age of two in a large cohort of Puerto Rican, Mexican American, and African American children.

MEASUREMENTS AND MAIN RESULTS

While early-life respiratory illnesses were associated with greater asthma odds in Puerto Ricans, Mexican Americans, and African Americans, these associations were stronger among Puerto Rican children. Specifically, in Puerto Ricans, the odds was 6.15 (95% CI: 4.21-9.05) if the child reported at least one of the following respiratory illness: URI, pneumonia, bronchitis or bronchiolitis. The odds were also higher in Puerto Ricans when considering these conditions separately.

CONCLUSIONS

We observed population-specific associations between early-life respiratory illnesses and asthma, which were especially significant and stronger in Puerto Ricans. Taken together with the known high burden of RSV in Puerto Rico, our results may help explain the high burden of asthma in Puerto Ricans.

Type 2 and interferon inflammation strongly regulate SARS-CoV-2 related gene expression in the airway epithelium

Coronavirus disease 2019 (COVID-19) outcomes vary from asymptomatic infection to death. This disparity may reflect different airway levels of the SARS-CoV-2 receptor, ACE2, and the spike protein activator, TMPRSS2. Here we explore the role of genetics and co-expression networks in regulating these genes in the airway, through the analysis of nasal airway transcriptome data from 695 children. We identify expression quantitative trait loci (eQTL) for both ACE2 and TMPRSS2, that vary in frequency across world populations. Importantly, we find TMPRSS2 is part of a mucus secretory network, highly upregulated by T2 inflammation through the action of interleukin-13, and that interferon response to respiratory viruses highly upregulates ACE2 expression. Finally, we define airway responses to coronavirus infections in children, finding that these infections upregulate IL6 while also stimulating a more pronounced cytotoxic immune response relative to other respiratory viruses. Our results reveal mechanisms likely influencing SARS-CoV-2 infectivity and COVID-19 clinical outcomes.

Forecasting health effects potentially associated with the relocation of a major air pollution source

Epidemiological studies often focus on risk assessments associated with exposures to specific air pollutants or proximity to different air pollution sources. Although this information is essential for devising informed health policies, it is not always helpful when it comes to the estimation of potential health effects associated with the introduction or relocation of local health hazards. In this paper, we suggest a novel approach to forecasting the morbidity-reduction impact of hypothetical removal of a major air pollution source from a densely populated urban area. The proposed approach is implemented in three stages. First, we identify and measure the strength of association of individual environmental factors with local morbidity patterns. Next, we use the estimated models to simulate the impact of removal of the pollution source under analysis and its replacement by green areas. Using this assessment, we then estimate potential changes in the local morbidity rates by mutually comparing the observed risk surface of disease with the risk surface simulated by modelling. To validate the proposed approach empirically, we use childhood asthma morbidity data available for a major metropolitan area in Israel, which hosts a large petrochemical complex. According to our estimates, relocation of the petrochemical complex in question is expected to result in about 70% drop in the childhood asthma morbidity rate area-wide. To the best of our knowledge, the present study is the first that suggests an operational approach to incorporating epidemiological assessments as an input for urban development plans related to local sources of air pollution.

Structural and Social Determinants of Health in Asthma in Developed Economies: a Scoping Review of Literature Published Between 2014 and 2019

PURPOSE OF REVIEW

Using the WHO Conceptual Framework for Action on the Social Determinants of Health, this review provides a discussion of recent epidemiologic, mechanistic, and intervention studies of structural and social determinants of health and asthma outcomes covering the period from 2014 to 2019.

RECENT FINDINGS

A majority of studies and interventions to date focus on the intermediary determinants of health (e.g., housing), which as the name suggests, exist between the patient and the upstream structural determinants of health (e.g., housing policy). Race/ethnicity remains a profound social driver of asthma disparities with cumulative risk from many overlapping determinants. A growing number of studies on asthma are beginning to elucidate the underlying mechanisms that connect social determinants to human disease. Several effective interventions have been developed, though a need for large-scale policy research and innovation remains. Strong evidence supports the key role of the structural determinants, which generate social stratification and inequity, in the development and progression of asthma; yet, interventions in this realm are challenging to develop and therefore infrequent. Proximal, intermediary determinants have provided a natural starting point for interventions, though structural interventions have the most potential for major impact on asthma outcomes. Further research to investigate the interactive effect of multiple determinants, as well as intervention studies, specifically those that are cross-sector and propose innovative strategies to target structural determinants, are needed to address asthma morbidities, and more importantly, close the asthma disparity gap.

Mechanisms and Management of Asthma Exacerbations

Acute asthma remains an important medical emergency, the most frequent cause of acute admissions in children and a major source of morbidity for adults with asthma. In all ages with asthma, the presence of exacerbations is an important defining characteristic of asthma severity. In this review, we assess the epidemiology of acute asthma, the triggers of acute exacerbations, and the mechanisms that underlie these exacerbations. We also assess current treatments that prevent exacerbations, with an emphasis on the role of type 2 airway inflammation in the context of acute exacerbations and the novel treatments that effectively target this. Finally we review current management strategies of the exacerbations themselves.

Using community priorities and misconceptions about asthma as a vessel for community-led education among Hispanics

OBJECTIVES

In New York City, asthma prevalence is greater in Hispanics than non-Hispanics for both children (10.9% vs. 7.4%) and adults (9.0% vs. 6.3%). Disparities in asthma management among Hispanics are found to arise, in part, from a limited education about asthma. Using elements of Community Based Participatory Research (CBPR), we worked with the community to identify asthma priorities and misconceptions among Hispanics and used that information to develop a tailored asthma educational tool-the Asthma Training Modules (ATMs).

METHODS

Over the past 3 years (2016, 2017, and 2018), we conducted educational asthma workshops to collect and analyze information to develop the ATMs and a summary of the ATMs in an Asthma Educational Card (AEC). We trained 6 Asthma-Community-Leaders using the ATMs, who assembled community members for teaching sessions using the AEC. Participants completed a pre-and-post asthma knowledge questionnaire.

RESULTS

We identified asthma priorities and misconceptions themed on: culturally relevant resources for Hispanics, symptom and trigger recognition, and treatments. A total of 104 participants attended the teaching sessions led by Asthma-Community-Leaders and participants' mean knowledge score increased from 64% pre-teaching to 85% post-teaching, (p < 0.01).

CONCLUSION

Our community-led education, which included a tailored asthma educational tool and trained Asthma-Community-Leaders, successfully improved asthma knowledge among Hispanics. Further studies are warranted to determine whether these results are reproducible among a larger cohort and what the comparative effectiveness of our intervention as compared to other education-based interventions.

Racial/Ethnic-Specific Differences in the Effects of Inhaled Corticosteroid Use on Bronchodilator Response in Patients With Asthma

American Thoracic Society guidelines recommend inhaled corticosteroid (ICS) therapy, plus a short-acting bronchodilator, in patients with persistent asthma. However, few prior studies have examined the efficacy of this combination in children of all racial/ethnic groups. We evaluated the association between ICS use and bronchodilator response (BDR) in three pediatric populations with persistent asthma (656 African American, 916 Puerto Rican, and 398 Mexican American children). The association was assessed using multivariable quantile regression. After adjusting for baseline forced expiratory volume in one second and use of controller medications, ICS use was significantly associated with increased BDR only among Mexican Americans (1.56%, P = 0.028) but not African Americans (0.49%, P = 0.426) or Puerto Ricans (0.16%, P = 0.813). Our results demonstrate that ICS augmentation is disproportionate across racial/ethnic groups, where improved BDR is observed in Mexican Americans only. This study highlights the complexities of treating asthma in children, and reinforces the importance of investigating the influence of race/ethnicity on pharmacological response.

Ambient air pollution, asthma drug response, and telomere length in African American youth

BACKGROUND

Telomere length (TL) can serve as a potential biomarker for conditions associated with chronic oxidative stress and inflammation, such as asthma. Air pollution can induce oxidative stress. Understanding the relationship between TL, asthma, and air pollution is important for identifying risk factors contributing to unhealthy aging in children.

OBJECTIVES

We sought to investigate associations between exposures to ambient air pollutants and TL in African American children and adolescents and to examine whether African ancestry, asthma status, and steroid medication use alter the association.

METHODS

Linear regression was used to examine associations between absolute telomere length (aTL) and estimated annual average residential ozone (O3) and fine particulate matter with a diameter of 2.5 μm or less (PM2.5) exposures in a cross-sectional analysis of 1072 children in an existing asthma case-control study. African ancestry, asthma status, and use of steroid medications were examined as effect modifiers.

RESULTS

Participants' aTLs were measured by using quantitative PCR. A 1-ppb and 1 μg/m3 increase in annual average exposure to O3 and PM2.5 were associated with a decrease in aTL of 37.1 kilo-base pair (kb; 95% CI, -66.7 to -7.4 kb) and 57.1 kb (95% CI, -118.1 to 3.9 kb), respectively. African ancestry and asthma were not effect modifiers; however, exposure to steroid medications modified the relationships between TL and pollutants. Past-year exposure to O3 and PM2.5 was associated with shorter TLs in patients without steroid use.

CONCLUSION

Exposure to air pollution was associated with shorter TLs in nonasthmatic children and adolescents. This was not the case for asthmatic children as a group, but those receiving steroid medication had less shortening than those not using steroids. Reduced exposure to air pollution in childhood might help to preserve TL.

High Education Level Protects European Americans but Not African Americans Against Chronic Obstructive Pulmonary Disease: National Health Interview Survey

BACKGROUND

Education level reduces the risk of chronic diseases (CDs), including Chronic Obstructive Pulmonary Disease (COPD). Minorities' Diminished Returns, however, refer to smaller health benefits of socioeconomic position (SEP) improvement for racial and ethnic minorities compared to majority groups. It is not known if MDRs exist for the effects of education level on COPD for African Americans (AAs), relative to European Americans (EAs).

AIMS

Using a nationally representative sample, the current study explored racial and ethnic variation in the association between education level and COPD among American adults.

METHODS

Data came from the National Health Interview Survey (NHIS 2015), a national survey. A total of 25,488 adults (18+ years old) were included in the study. From this number, 4,533 (17.8%) were AAs and 20,955 (82.2%) were EAs. Education level was the independent variable. Outcome was COPD. Age, gender, and income were the covariates. Race/ethnicity was the moderator.

RESULTS

Overall, education level was inversely associated with the odds of COPD. A statistically significant interaction was found between race/ethnicity and education level on odds of COPD, indicating smaller effect of education for AAs compared to EAs.

CONCLUSIONS

In line with the Minorities' Diminished Returns (MDRs), highly educated AAs remained at high risk for COPD, a pattern which is not observed for EAs. Policies that exclusively address racial/ethnic inequalities in SEP may not be enough for eliminating racial/ethnic inequalities in COPD in the US. Public policies must go beyond equalizing SEP and address structural and environmental barriers that disproportionately increase risk of COPD in AAs across SEP levels. Future research should test if residential segregation and exposure to air pollutants contributes to high prevalence of COPD in highly educated AAs. Research is needed on multi-level interventions that may minimize MDR-related health disparities.

Comparison of severity of asthma hospitalization between African American and Hispanic children in the Bronx

Objective: There are racial and ethnic disparities in childhood asthma burden and outcomes. Although there have been comparisons between whites and minorities, there are few between minority groups. This study aimed to compare characteristics of asthma hospitalizations in African American and Hispanic children.Methods: A retrospective chart review was conducted to compare asthma characteristics between African American and Hispanic children aged 2-18 years hospitalized at an urban, tertiary care hospital for an acute asthma exacerbation. Length of stay (LOS), need for intensive care unit (ICU), and need for additional medications or respiratory support were compared between the groups.Results: Of the 925 children that met the inclusion criteria, 64% were Hispanic and 36% were African American. The groups were similar in age, gender, insurance status, and weight classification. African American children were more likely to have severe persistent asthma (12% vs. 7%, p = .02). They were also more likely to require magnesium sulfate (45% vs. 32%, p < .001) and admission to the ICU from the emergency department (ED) (14% vs. 8%, p = .01), which were independent of asthma severity. There was no significant difference in LOS or other characteristics of hospitalization.Conclusions: African American children hospitalized for asthma have more severe exacerbations compared to Hispanic children, which is independent of their asthma severity. However, this was not associated with longer LOS, which may indicate greater responsiveness to inpatient asthma management. Further investigation is needed to understand the mechanisms underlying asthma and exacerbation severity among minority groups.

An admixture mapping meta-analysis implicates genetic variation at 18q21 with asthma susceptibility in Latinos

BACKGROUND

Asthma is a common but complex disease with racial/ethnic differences in prevalence, morbidity, and response to therapies.

OBJECTIVE

We sought to perform an analysis of genetic ancestry to identify new loci that contribute to asthma susceptibility.

METHODS

We leveraged the mixed ancestry of 3902 Latinos and performed an admixture mapping meta-analysis for asthma susceptibility. We replicated associations in an independent study of 3774 Latinos, performed targeted sequencing for fine mapping, and tested for disease correlations with gene expression in the whole blood of more than 500 subjects from 3 racial/ethnic groups.

RESULTS

We identified a genome-wide significant admixture mapping peak at 18q21 in Latinos (P = 6.8 × 10-6), where Native American ancestry was associated with increased risk of asthma (odds ratio [OR], 1.20; 95% CI, 1.07-1.34; P = .002) and European ancestry was associated with protection (OR, 0.86; 95% CI, 0.77-0.96; P = .008). Our findings were replicated in an independent childhood asthma study in Latinos (P = 5.3 × 10-3, combined P = 2.6 × 10-7). Fine mapping of 18q21 in 1978 Latinos identified a significant association with multiple variants 5' of SMAD family member 2 (SMAD2) in Mexicans, whereas a single rare variant in the same window was the top association in Puerto Ricans. Low versus high SMAD2 blood expression was correlated with case status (13.4% lower expression; OR, 3.93; 95% CI, 2.12-7.28; P < .001). In addition, lower expression of SMAD2 was associated with more frequent exacerbations among Puerto Ricans with asthma.

CONCLUSION

Ancestry at 18q21 was significantly associated with asthma in Latinos and implicated multiple ancestry-informative noncoding variants upstream of SMAD2 with asthma susceptibility. Furthermore, decreased SMAD2 expression in blood was strongly associated with increased asthma risk and increased exacerbations.

Acculturation is associated with asthma burden and pulmonary function in Latino youth: The GALA II study

BACKGROUND

Acculturation is an important predictor of asthma in Latino youth, specifically Mexican Americans. Less is known about acculturation and pulmonary function measures.

OBJECTIVE

We sought to estimate the association of acculturation measures with asthma and pulmonary function in Latino youth and determine whether this association varies across Latino subgroups.

METHODS

We included 1849 Latinos (302 Caribbean Spanish, 193 Central or South Americans, 1136 Mexican Americans, and 218 other Latino children) aged 8 to 21 years from 4 urban regions in the United States. Acculturation measures include nativity status, age of immigration, language of preference, and generation in the United States. We used multivariable logistic and linear regression models to quantify the association of acculturation factors with the presence of asthma (case-control study) and pulmonary function (case-only study), adjusting for demographic, socioenvironmental, and clinical variables.

RESULTS

For all acculturation measures (nativity status, age of immigration, language of preference, and generation in the United States), greater levels of acculturation were associated with greater odds of asthma. Among cases, high (English preference) and medium (equal preference for Spanish and English) levels of language acculturation were associated with decreased bronchodilator response compared with low (Spanish preference) levels (P = .009 and .02, respectively). Similarly, high language acculturation was associated with increased FEV₁ compared with low language acculturation (P = .02). There was insufficient evidence of heterogeneity for associations across Latino subgroups.

CONCLUSIONS

Acculturation was associated with diagnosed asthma and pulmonary function in Latino children and is an important factor to consider in the management of Latino youth with asthma.