Effect of secondhand smoke on asthma control among black and Latino children

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.

Secondhand Smoking and the Fetus: A Bibliometric Analysis

Background

Bibliometric analysis may indicate the most active specialist, authors, and journals in a given research field. To the authors' knowledge, there is no bibliometric analysis to provide a macroscopic overview in the field of secondhand smoke that harms non-smoker.

Methods

Using the bibliometric method, 644 articles that were present in the Scopus database between 1973-2020 on the subject were considered. The data were analyzed by two visualization and science-mapping software called Bibliometrix and VoS Viewer. Also, reference publication year stereoscopy and Co-Citation historiography were used. In the qualitative analysis, 52 articles were selected that had the most citation and were analyzed.

Results

In this paper, the findings show that the documents were published in 364 sources with an average citation per document of 25.14 and more than 3 authors or nearly 4 authors per document. The peak reference publication year stereoscopy happened in the year 199 with 974 references. The countries with the highest number of MCP were the USA, China, and Spain. The "International Journal of Environmental Research" and "Public Health", has raised their publications in the field of secondhand smoke and pregnancy rapidly since 2003. Among the titles, "passive smoking" was the most used.

Conclusion

The study highlights the importance of understanding the harmful effects of secondhand smoke on the developing fetus. The findings also shed light on key research trends, influential authors, and active research areas, which can guide future studies and support evidence-based decision-making in the field of maternal and child health.

Gene expression in African Americans, Puerto Ricans and Mexican Americans reveals ancestry-specific patterns of genetic architecture

We explored ancestry-related differences in the genetic architecture of whole-blood gene expression using whole-genome and RNA sequencing data from 2,733 African Americans, Puerto Ricans and Mexican Americans. We found that heritability of gene expression significantly increased with greater proportions of African genetic ancestry and decreased with higher proportions of Indigenous American ancestry, reflecting the relationship between heterozygosity and genetic variance. Among heritable protein-coding genes, the prevalence of ancestry-specific expression quantitative trait loci (anc-eQTLs) was 30% in African ancestry and 8% for Indigenous American ancestry segments. Most anc-eQTLs (89%) were driven by population differences in allele frequency. Transcriptome-wide association analyses of multi-ancestry summary statistics for 28 traits identified 79% more gene-trait associations using transcriptome prediction models trained in our admixed population than models trained using data from the Genotype-Tissue Expression project. Our study highlights the importance of measuring gene expression across large and ancestrally diverse populations for enabling new discoveries and reducing disparities.

National Heart, Lung, and Blood Institute: Social Determinants of Health Research, Fiscal Year 2008-2020

INTRODUCTION

Social determinants of health influence the prevention, treatment, and progression of chronic diseases, including heart, lung, blood, and sleep diseases and conditions. Healthy People 2020 classifies Social Determinants of Health into 5 subcategories: (1) Neighborhood and Built Environment, (2) Education, (3) Economic Stability, (4) Social and Community Context, and (5) Health and Health Care. This study's goal is to characterize the National Heart, Lung, and Blood Institute's Fiscal Year 2008-2020 funding in overall Social Determinants of Health research and in the Healthy People 2020 subcategories.

METHODS

The Social Determinants of Health Research, Condition, and Disease Categorization code was used to identify funded grants in this area. Natural language processing methods further categorized grants into the 5 Healthy People 2020 Social Determinants of Health subcategories.

RESULTS

There were 915 (∼4.3%) social determinants of health‒funded grants from 2008 to 2020 representing $1,034 billion in direct costs. Most grants were relevant to cardiovascular diseases (n=653), with a smaller number relevant to lung diseases (n=186), blood diseases (n=47), and translational and implementation science (n=29). Grants fit multiple Social Determinants of Health subcategories with the majority identified as Health and Health Care (62%) and Economic Stability (61%). The number of National Heart, Lung, and Blood Institute social determinants of health grants awarded increased by 127% from Fiscal Year 2008 to Fiscal Year 2020.

CONCLUSIONS

This study identifies Social Determinants of Health grants funded by the National Heart, Lung, and Blood Institute during 2008‒2020. Enhancing the understanding of these determinants and developing effective interventions will ultimately help to advance the mission of the National Heart, Lung, and Blood Institute.

Unraveling racial disparities in asthma emergency department visits using electronic healthcare records and machine learning

OBJECTIVE

Hospital emergency department (ED) visits by asthmatics differ based on race and season. The objectives of this study were to investigate season- and race-specific disparities for asthma risk, and to identify environmental exposure variables associated with ED visits among more than 42,000 individuals of African American (AA) and European American (EA) descent identified through electronic health records (EHRs).

METHODS

We examined data from 42,375 individuals (AAs = 14,491, EAs = 27,884) identified in EHRs. We considered associated demographic (race, age, gender, insurance), clinical (smoking status, ED visits, FEV1%), and environmental exposures data (mold, pollen, and pollutants). Machine learning techniques, including random forest (RF), extreme gradient boosting (XGB), and decision tree (DT) were used to build and identify race- and -season-specific predictive models for asthma ED visits.

RESULTS

Significant differences in ED visits and FEV1% among AAs and EAs were identified. ED visits by AAs was 32.0% higher than EAs and AAs had 6.4% lower FEV1% value than EAs. XGB model was used to accurately classify asthma patients visiting ED into AAs and EAs. Pollen factor and pollution (PM2.5, PM10) were the key variables for asthma in AAs and EAs, respectively. Age and cigarette smoking increase asthma risk independent of seasons.

CONCLUSIONS

In this study, we observed racial and season-specific disparities between AAs and EAs asthmatics for ED visit and FEV1% severity, suggesting the need to address asthma disparities through key predictors including socio-economic status, particulate matter, and mold.

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.

A genome-wide study of DNA methylation in white blood cells and asthma in Latino children and youth

Latinos are heavily affected with childhood asthma. Little is known about epigenetic mechanisms of asthma in Latino youth. We conducted a meta-analysis of two epigenome-wide association studies (EWAS) of asthma, using DNA from white blood cells (WBCs) from 1,136 Latino children and youth aged 6 to 20 years. Genes near the top CpG sites in this EWAS were examined in a pathway enrichment analysis, and we then assessed whether our results replicated those from publicly available data from three independent EWAS conducted in non-Latino populations. We found that DNA methylation profiles differed between subjects with and without asthma. After adjustment for covariates and multiple testing, two CpGs were differentially methylated at a false discovery rate (FDR)-adjusted P < 0.1, and 193 CpG sites were differentially methylated at FDR-adjusted P < 0.2. The two top CpGs are near genes relevant to inflammatory signalling, including CAMK1D (Calcium/Calmodulin Dependent Protein Kinase ID) and TIGIT (T Cell Immunoreceptor With Ig And ITIM Domains). Moreover, 25 genomic regions were differentially methylated between subjects with and without asthma, at Šidák-corrected P < 0.10. An enrichment analysis then identified the TGF-beta pathway as most relevant to asthma in our analysis, and we replicated some of the top signals from publicly available EWAS datasets in non-Hispanic populations. In conclusion, we have identified novel epigenetic markers of asthma in WBCs from Latino children and youth, while also replicating previous results from studies conducted in non-Latinos.

Lung Function in African American Children with Asthma Is Associated with Novel Regulatory Variants of the KIT Ligand KITLG/SCF and Gene-By-Air-Pollution Interaction

Baseline lung function, quantified as forced expiratory volume in the first second of exhalation (FEV1), is a standard diagnostic criterion used by clinicians to identify and classify lung diseases. Using whole-genome sequencing data from the National Heart, Lung, and Blood Institute Trans-Omics for Precision Medicine project, we identified a novel genetic association with FEV1 on chromosome 12 in 867 African American children with asthma (P = 1.26 × 10-8, β = 0.302). Conditional analysis within 1 Mb of the tag signal (rs73429450) yielded one major and two other weaker independent signals within this peak. We explored statistical and functional evidence for all variants in linkage disequilibrium with the three independent signals and yielded nine variants as the most likely candidates responsible for the association with FEV1 Hi-C data and expression QTL analysis demonstrated that these variants physically interacted with KITLG (KIT ligand, also known as SCF), and their minor alleles were associated with increased expression of the KITLG gene in nasal epithelial cells. Gene-by-air-pollution interaction analysis found that the candidate variant rs58475486 interacted with past-year ambient sulfur dioxide exposure (P = 0.003, β = 0.32). This study identified a novel protective genetic association with FEV1, possibly mediated through KITLG, in African American children with asthma. This is the first study that has identified a genetic association between lung function and KITLG, which has established a role in orchestrating allergic inflammation in asthma.

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.

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.

In utero tobacco smoke exposure, DNA methylation, and asthma in Latino children

BACKGROUND

Maternal smoking during pregnancy is a risk factor for chronic disease later in life and has been associated with variability of DNA methylation at specific cytosine-phosphate-guanine (CpG) loci. We assessed the role of DNA methylation as a potential mediator of adverse effects of in utero tobacco smoke exposures on asthma outcomes in Latino children from the US mainland and Puerto Rico.

METHODS

Relationships between self-reported exposure and DNA methylation at CpG loci previously reported to be associated with maternal smoking were assessed in a subsample consisting of 572 children aged 8-21 years (310 cases with asthma, 262 healthy controls), sampled from a larger asthma case-control study. Subsequently, we assessed associations between top loci and asthma-related outcomes, followed by mediation analysis for loci for which associations with outcomes were observed.

RESULTS

Self-reported maternal smoking was associated with a -1.5% (95% confidence interval (CI) = -2.4%, -0.6%) lower methylation at CpG locus cg05575921 on the AHRR gene; a 1% increase in DNA methylation at the same locus resulted in an odds ratio (OR) of 0.90 (95% CI = 0.83, 0.96) for the odds of asthma. The OR for the indirect effect of maternal smoking on asthma mediated through methylation at the cg05575921 locus was 1.18 (95% CI = 1.07, 1.68), compared to the OR for the total effect of exposure in the parent study of 1.48 (95% CI = 1.03, 2.11).

CONCLUSIONS

Our findings suggest potential mediation by DNA methylation in the association between maternal smoking during pregnancy and asthma status.

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.

Secondhand smoke exposure and asthma outcomes among African-American and Latino children with asthma

BACKGROUND

Secondhand smoke (SHS) exposures have been linked to asthma-related outcomes but quantitative dose-responses using biomarkers of exposure have not been widely reported.

OBJECTIVES

Assess dose-response relationships between plasma cotinine-determined SHS exposure and asthma outcomes in minority children, a vulnerable population exposed to higher levels of SHS and under-represented in the literature.

METHODS

We performed analyses in 1172 Latino and African-American children with asthma from the mainland USA and Puerto Rico. We used logistic regression to assess relationships of cotinine levels ≥0.05 ng/mL with asthma exacerbations (defined as asthma-related hospitalisations, emergency room visits or oral steroid prescription) in the previous year and asthma control. The shape of dose-response relationships was assessed using a continuous exposure variable in generalised additive logistic models with penalised splines.

RESULTS

The OR for experiencing asthma exacerbations in the previous year for cotinine levels ≥0.05 ng/mL, compared with <0.05 ng/mL, was 1.40 (95% CI 1.03 to 1.89), while the OR for poor asthma control was 1.53 (95% CI 1.12 to 2.13). Analyses for dose-response relationships indicated increasing odds of asthma outcomes related with increasing exposure, even at cotinine levels associated with light SHS exposures.

CONCLUSIONS

Exposure to SHS was associated with higher odds of asthma exacerbations and having poorly controlled asthma with an increasing dose-response even at low levels of exposure. Our results support the conclusion that there are no safe levels of SHS exposures.

Exploring the barriers and incentive architecture for modifying smoke exposures among asthmatics

BACKGROUND

The socio-structural barriers for reducing secondhand smoke exposure (SHSe) among children with asthma may be insurmountable for low-income caregivers. Health promoting financial incentives (HPFIs) are increasingly being used in the adult population to motivate and sustain tobacco-reduction behaviors. We assessed barriers to SHSe reduction and means to overcome them through the design of an HPFI-based, caregiver-targeted SHSe reduction study.

METHODS

Using a mixed-methods design, we conducted semi-structured in-depth interviews among low-income primary caregivers of children with asthma residing in Baltimore City. Quantitative data using an online survey were used to augment interview findings.

RESULTS

Home smoking restrictions were a frequently referenced strategy for decreasing SHSe, but interviewees (n = 22) described the complex social pressures that undermine reduction efforts. Caregivers redirected conversations from broadly implemented smoking bans towards targeted reduction strategies among mothers and members of their social network who are active smokers. Participants converged on the notion that sustainable SHSe reduction strategies are realizable only for mothers who are active smokers, possess high self-efficacy and social structures that promote cessation. Survey data (n = 56) clarified the multiple contexts that underlie pediatric SHSe and preferred HPFI architecture that included fixed, recurrent payments contingent on reduced nicotine biomarkers and completion of basic asthma education classes.

CONCLUSIONS

Based on the combined analyses, we envision testing a HPFI-based study design whose optimal target population included low-income caregivers and members of their social network where incentives are tied to pediatric biomarkers and asthma education-an integrated approach that has not yet been used in pediatric tobacco studies.

Characteristics and Prevalence of Asthma/Chronic Obstructive Pulmonary Disease Overlap in the United States

RATIONALE

The asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) occurs in patients with fixed airway obstruction that defines COPD and with symptoms more typical of asthma. ACOS prevalence and the comorbidities associated with this syndrome have been inadequately characterized.

OBJECTIVES

Because this population is prone to more frequent exacerbations, we hypothesized that comorbidities associated with ACOS are higher than those with COPD, asthma, and control populations in the United States.

METHODS

We examined the self-reported demographics, smoking status, comorbidities, and hospitalization or emergency department (ED) visitation experience among study respondents older than 35 years of age (n = 90,851) in the Behavioral Risk Factor Surveillance System survey and compared participants with ACOS to COPD, asthma, and control groups. We used logistic regression to compare ACOS and COPD populations to model the impact of comorbid conditions and hospitalization/ED visits after adjusting for demographic factors and smoking status to generate odds ratios and confidence intervals.

MEASUREMENTS AND MAIN RESULTS

The U.S. prevalence of ACOS was 3.2%, COPD alone was 6.0%, and both increased with age. Respondents with ACOS were younger (64.0 ± 11.7 yr) than respondents with COPD (67.1 ± 11.8 yr) and older than respondents with asthma (59.0 ± 13.1 yr; P < 0.0001). The prevalence of comorbidities was higher in the group with ACOS and COPD than in asthma or control groups. The ACOS group had a higher body mass index, lower income, and lower education than other groups. The ACOS group was more likely to have at least one comorbidity (90.2 vs. 84%, P < 0.0001), more hospitalization or ED visits (22.0 vs. 13.2%, P < 0.0001), less exercise (50.0 vs. 58.6%, P = 0.0024), and more disability (70.8 vs. 58.6%, P < 0.0001) than the COPD group.

CONCLUSIONS

The patients with a dual diagnosis of asthma and COPD are younger and with more disparities than those diagnosed with COPD alone. ACOS has a higher burden of self-reported comorbidity, disability, and hospitalization or ED visitation than COPD alone.

Perceptions of Secondhand and Thirdhand Smoke Among Hispanic Residents of Multiunit Housing

Despite the progressive adoption of smoking bans in public spaces, children living in multi-unit housing remain at risk of exposure to secondhand smoke (SHS) and thirdhand smoke (THS). Hispanic populations in California are particularly vulnerable to the harmful effects of SHS and THS because a large proportion of Hispanics live in multi-unit housing. Three focus groups were conducted in the fall of 2012 (in Spanish and English, N = 24) to understand Hispanics' knowledge of and experiences with SHS and THS, including barriers to avoiding smoke exposure and strategies for protecting their homes from smoke. Hispanic residents reported unpleasant experiences with SHS and THS and were generally knowledgeable about the adverse health effects, although they were not familiar with the term "thirdhand smoke." Some participants also mentioned marijuana smoke as a potential health hazard. Hispanic cultural values made participants reluctant to confront their neighbors but also motivated them to find ways to protect their families from smoke. Potential solutions included working with the smokers to designate a smoking area and gaining support from the building owners. Broad smoking policies should be implemented to help Hispanic residents overcome cultural and social barriers to smoke free air.

The environment, epigenome, and asthma

Asthma prevalence has been on the increase, especially in North America compared with other continents. However, the prevalence of asthma differs worldwide, and in many countries the prevalence is stable or decreasing. This highlights the influence of environmental exposures, such as allergens, air pollution, and the environmental microbiome, on disease etiology and pathogenesis. The epigenome might provide the unifying mechanism that translates the influence of environmental exposures to changes in gene expression, respiratory epithelial function, and immune cell skewing that are hallmarks of asthma. In this review we will introduce the concept of the environmental epigenome in asthmatic patients, summarize previous publications of relevance to this field, and discuss future directions.

Self-reported racial/ethnic discrimination and bronchodilator response in African American youth with asthma

IMPORTANCE

Asthma is a multifactorial disease composed of endotypes with varying risk profiles and outcomes. African Americans experience a high burden of asthma and of psychosocial stress, including racial discrimination. It is unknown which endotypes of asthma are vulnerable to racial/ethnic discrimination.

OBJECTIVE

We examined the association between self-reported racial/ethnic discrimination and bronchodilator response (BDR) among African American youth with asthma ages 8 to 21 years (n = 576) and whether this association varies with tumor necrosis factor alpha (TNF-α) level.

MATERIALS AND METHODS

Self-reported racial/ethnic discrimination was assessed by a modified Experiences of Discrimination questionnaire as none or any. Using spirometry, BDR was specified as the mean percentage change in forced expiratory volume in one second before and after albuterol administration. TNF-α was specified as high/low levels based on our study population mean. Linear regression was used to examine the association between self-reported racial/ethnic discrimination and BDR adjusted for selected characteristics. An interaction term between TNF-α levels and self-reported racial/ethnic discrimination was tested in the final model.

RESULTS

Almost half of participants (48.8%) reported racial/ethnic discrimination. The mean percent BDR was higher among participants reporting racial/ethnic discrimination than among those who did not (10.8 versus 8.9, p = 0.006). After adjustment, participants reporting racial/ethnic discrimination had a 1.7 (95% CI: 0.36-3.03) higher BDR mean than those not reporting racial/ethnic discrimination. However, we found heterogeneity of this association according to TNF-α levels (p-interaction = 0.040): Among individuals with TNF-α high level only, we observed a 2.78 higher BDR mean among those reporting racial/ethnic discrimination compared with those not reporting racial/ethnic discrimination (95%CI: 0.79-4.77).

CONCLUSIONS

We found BDR to be increased in participants reporting racial/ethnic discrimination and this association was limited to African American youth with TNF-α high asthma, an endotype thought to be resistant to traditional asthma medications. These results support screening for racial/ethnic discrimination in those with asthma as it may reclassify disease pathogenesis.

Differential methylation between ethnic sub-groups reflects the effect of genetic ancestry and environmental exposures

Populations are often divided categorically into distinct racial/ethnic groups based on social rather than biological constructs. Genetic ancestry has been suggested as an alternative to this categorization. Herein, we typed over 450,000 CpG sites in whole blood of 573 individuals of diverse Hispanic origin who also had high-density genotype data. We found that both self-identified ethnicity and genetically determined ancestry were each significantly associated with methylation levels at 916 and 194 CpGs, respectively, and that shared genomic ancestry accounted for a median of 75.7% (IQR 45.8% to 92%) of the variance in methylation associated with ethnicity. There was a significant enrichment (p=4.2×10-64) of ethnicity-associated sites amongst loci previously associated environmental exposures, particularly maternal smoking during pregnancy. We conclude that differential methylation between ethnic groups is partially explained by the shared genetic ancestry but that environmental factors not captured by ancestry significantly contribute to variation in methylation.

Impacts of low socioeconomic status and polycyclic aromatic hydrocarbons exposure on lung function among a community-based Chinese population

Lung function is related to socioeconomic status (SES) and exposure to polycyclic aromatic hydrocarbons (PAHs). However, joint effect of SES and exposure to PAHs on lung function has been largely unknown. We aimed to investigate joint effects of SES and urinary OH-PAHs levels on lung function parameters. This study included 2739 Wuhan participants from the baseline survey of the Wuhan-Zhuhai (WHZH) Cohort Study (n=3053). They completed the questionnaire, physical examination and provided blood and urine samples. Twelve urinary monohydroxy-PAHs metabolites (OH-PAHs) and lung function were measured by gas chromatography-mass spectrometry and digital spirometers, respectively. Individuals with low educational levels and low or high levels of urinary ΣOH-PAHs had a 3.5% (95% CI: -5.4, -1.6%) or 4.2% (95% CI: -6.1, -2.3%) reduction in the ratio of forced expiratory volume in 1s to forced vital capacity (FEV1/FVC), respectively, and those with middle levels of education and high levels of urinary ΣOH-PAHs had a 2.1% (95% CI: -5.4, -1.6%) reduction in the FEV1/FVC ratio, rather than those with high levels of education and low levels of urinary ΣOH-PAHs. Individuals with low levels of education had a -3.0% (95% CI: -4.4, -1.6%) reduction in FEV1/FVC compared with individuals with high levels of education. Urinary OH-PAHs levels were marginally negatively related to FEV1 in all participants (p=0.073). The results indicated that there was a prominent effect of low levels of education and higher exposure to PAHs on lung function decline, indicating that it is a necessary to take measures to promote the education level and reduce exposure to environmental PAHs.

Perceived Discrimination Associated With Asthma and Related Outcomes in Minority Youth: The GALA II and SAGE II Studies

BACKGROUND

Asthma disproportionately affects minority populations and is associated with psychosocial stress such as racial/ethnic discrimination. We aimed to examine the association of perceived discrimination with asthma and poor asthma control in African American and Latino youth.

METHODS

We included African American (n = 954), Mexican American (n = 1,086), other Latino (n = 522), and Puerto Rican Islander (n = 1,025) youth aged 8 to 21 years from the Genes-Environments and Admixture in Latino Americans study and the Study of African Americans, Asthma, Genes, and Environments. Asthma was defined by physician diagnosis, and asthma control was defined based on the National Heart, Lung, and Blood Institute guidelines. Perceived racial/ethnic discrimination was assessed by the Experiences of Discrimination questionnaire, with a focus on school, medical, and public settings. We examined the associations of perceived discrimination with each outcome and whether socioeconomic status (SES) and global African ancestry modified these associations.

RESULTS

African American children reporting any discrimination had a 78% greater odds of experiencing asthma (OR, 1.78; 95% CI, 1.33-2.39) than did those not reporting discrimination. Similarly, African American children faced increased odds of poor asthma control with any experience of discrimination (OR, 1.97; 95% CI, 1.42-2.76) over their counterparts not reporting discrimination. These associations were not observed among Latino children. We observed heterogeneity of the association between reports of discrimination and asthma according to SES, with reports of discrimination increasing the odds of having asthma among low-SES Mexican American youth (interaction P = .01) and among high-SES other Latino youth (interaction P = .04).

CONCLUSIONS

Perceived discrimination is associated with increased odds of asthma and poorer control among African American youth. SES exacerbates the effect of perceived discrimination on having asthma among Mexican American and other Latino youth.

Role of Epigenetics in Biology and Human Diseases

For a long time, scientists have tried to describe disorders just by genetic or environmental factors. However, the role of epigenetics in human diseases has been considered from a half of century ago. In the last decade, this subject has attracted many interests, especially in complicated disorders such as behavior plasticity, memory, cancer, autoimmune disease, and addiction as well as neurodegenerative and psychological disorders. This review first explains the history and classification of epigenetic modifications, and then the role of epigenetic in biology and connection between the epigenetics and environment are explained. Furthermore, the role of epigenetics in human diseases is considered by focusing on some diseases with some complicated features, and at the end, we have given the future perspective of this field. The present review article provides concepts with some examples to reveal a broad view of different aspects of epigenetics in biology and human diseases.

Early smoke exposure is associated with asthma and lung function deficits in adolescents

OBJECTIVE

Early life tobacco smoke exposure may influence asthma, lung function and lung function growth into adolescence. We aimed to determine the associations between perinatal smoke exposure and asthma and lung function up to 18 years of age.

METHODS

We prospectively recorded perinatal parental smoking and measured respiratory outcomes at 12 and 18 years in the Melbourne Atopy Cohort Study (MACS), a longitudinal birth cohort. Multiple logistic regression was used to analyse the associations between perinatal smoke exposure and asthma at 12 (n = 370) and 18 years (n = 411). Multiple linear regression was used to investigate the relationship between perinatal smoking and: lung function (12 and 18 years) and lung function growth (between 12 and 18 years).

RESULTS

At 18 years, girls exposed to parental smoking during the perinatal period had increased odds of asthma (OR: 3.45, 95%CI: 1.36, 8.77), reduced pre-bronchodilator Forced expiratory volume in one-second (FEV₁) (-272 ml/s; -438, -107); FEV₁/ forced vital capacity (FVC) (-0.038; -0.065, -0.010); mid expiratory flow (MEF_25-75) (-430 ml/s; -798, -61), and reduced post-bronchodilator FEV₁/FVC (-0.028, -0.053, -0.004). No associations were found for boys (pre-bronchodilator FEV₁ 26ml/s; -202, 255; FEV₁/FVC 0.018; -0.013, 0.049).

CONCLUSIONS

Perinatal smoke may affect risk of asthma, reduce lung function and lung function growth in adolescence. Girls appear to be more susceptible than boys.

Asthma control and obesity in urban African American children

OBJECTIVE

To examine the relationship between body mass index (BMI), gender, age, controller medication use, household smoke exposure, season, and allergic rhinitis status with asthma control in a group of lower income, African American children. We hypothesized that non-obese children would have better asthma control.

METHODS

Baseline data from a longitudinal study of children in a school-based asthma program in a Midwest urban area were analyzed. 360 children, ages 4-15 years, who were enrolled in either the 2012-2013 or 2013-2014 program were included. Asthma control was classified using criteria from the 2007 National Asthma Education and Prevention Program. Multiple ordinal regression was performed.

RESULTS

The median age was 9 years, 61% had well-controlled asthma, and 29% were obese. The model included all main effects plus two interaction terms and was significant (χ²(7) = 22.17, p =.002). Females who were normal weight (OR, 2.78; 95% CI, 1.38-5.60, p =.004) or overweight (OR, 3.12; 95% CI, 1.26-7.72, p =.014) had better asthma control than obese females. For males, there were no differences by BMI category but males without allergic rhinitis had significantly better asthma control (OR, 2.23; 95% CI, 1.25-3.97, p =.006) than those with allergic rhinitis.

CONCLUSIONS

Non-obese girls and non-allergic males had better asthma control. Promotion of healthy activity and nutrition as well as management of allergic rhinitis should be part of the asthma plan in school-based programs in low income urban areas. Innovative approaches to address asthma care in low income populations are essential.

Maternal age and asthma in Latino populations

BACKGROUND

Younger maternal age at birth is associated with increased risk of asthma in offspring in European descent populations, but has not been studied in Latino populations.

OBJECTIVES

We sought to examine the relationship between maternal age at birth and prevalence of asthma in a nationwide study of Latino children.

METHODS

We included 3473 Latino children aged 8-21 years (1696 subjects with physician-diagnosed asthma and 1777 healthy controls) from five US centres and Puerto Rico recruited from July 2008 through November 2011. We used multiple logistic regression models to examine the effect of maternal age at birth on asthma in offspring overall and in analyses stratified by ethnic subgroup (Mexican American, Puerto Rican and other Latino). Secondary analyses evaluated the effects of siblings, acculturation and income on this relationship.

RESULTS

Maternal age < 20 years was significantly associated with decreased odds of asthma in offspring, independent of other risk factors (OR = 0.73, 95% CI: 0.57-0.93). In subgroup analyses, the protective effect of younger maternal age was observed only in Mexican Americans (OR = 0.53, 95% CI: 0.36, 0.79). In Puerto Ricans, older maternal age was associated with decreased odds of asthma (OR = 0.65, 95% CI: 0.44-0.97). In further stratified models, the protective effect of younger maternal age in Mexican Americans was seen only in children without older siblings (OR = 0.44, 95% CI: 0.23-0.81).

CONCLUSION AND CLINICAL RELEVANCE

In contrast to European descent populations, younger maternal age was associated with decreased odds of asthma in offspring in Mexican American women. Asthma is common in urban minority populations but the factors underlying the varying prevalence among different Latino ethnicities in the United States is not well understood. Maternal age represents one factor that may help to explain this variability.

Sensitization to mouse and cockroach allergens and asthma morbidity in urban minority youth: Genes-environments and Admixture in Latino American (GALA-II) and Study of African-Americans, Asthma, Genes, and Environments (SAGE-II)

BACKGROUND

Pest allergen sensitization is associated with asthma morbidity in urban youth but minimally explored in Latino populations. Specifically, the effect of mouse sensitization on the risk of asthma exacerbation has been unexplored in Latino subgroups.

OBJECTIVE

To evaluate whether pest allergen sensitization is a predictor of asthma exacerbations and poor asthma control in urban minority children with asthma.

METHODS

Latino and African American children (8-21 years old) with asthma were recruited from 4 sites across the United States. Logistic regression models evaluated the association of mouse or cockroach sensitization with asthma-related acute care visits or hospitalizations.

RESULTS

A total of 1,992 children with asthma in the Genes-environments and Admixture in Latino American (GALA-II) and Study of African-Americans, Asthma, Genes, and Environments (SAGE-II) cohorts were studied. Asthmatic children from New York had the highest rate of pest allergen sensitization (42% mouse, 56% cockroach), with the lowest rate in San Francisco (4% mouse, 8% cockroach). Mouse sensitization, more than cockroach, was associated with increased odds of acute care visits (adjusted odds ratio [aOR], 1.47; 95% CI, 1.07-2.03) or hospitalizations (aOR, 3.07; 95% CI, 1.81-5.18), even after controlling for self-reported race and site of recruitment. In stratified analyses, Mexican youth sensitized to mouse allergen did not have higher odds of asthma exacerbation. Other Latino and Puerto Rican youth sensitized to mouse had higher odds of hospitalization for asthma (aORs, 4.57 [95% CI, 1.86-11.22] and 10.01 [95% CI, 1.77-56.6], respectively) but not emergency department visits.

CONCLUSION

Pest allergen sensitization is associated with a higher odds of asthma exacerbations in urban minority youth. Puerto Rican and Other Latino youth sensitized to mouse were more likely to have asthma-related hospitalizations than Mexican youth.

The Impact of Tobacco Smoke Exposure on Childhood Asthma in a Medicaid Managed Care Plan

BACKGROUND

Tobacco smoke exposure increases breathing problems of children. Texas Children's Health Plan is a Managed Medicaid and Children's Health Insurance Program (CHIP) managed care provider. The aim of this study is to determine associations among tobacco smoke exposure, asthma prevalence, and asthma health-care utilization.

METHODS

Texas Children's Health Plan conducts an annual survey of members who have a physician visit. Questions were added to the survey in March 2010 about asthma and tobacco smoke exposure. Survey results for children < 18 years of age were matched to health plan claims data for the 12 months following the date of the physician visit.

RESULTS

A total of 22,470 parents of unique members/patients from birth to < 18 years of age participated in the survey. More whites than African Americans or Hispanics report that the child's mother is a smoker (19.5% vs 9.1% and vs 2.3%, respectively; P < .001). Compared with children whose mother does not smoke, parent report of asthma diagnosis and claims for dispensing of short-acting beta agonist medication are greater if the mother is a smoker (adjusted OR, 1.20 [95% CI, 1.03-1.40] and 1.24 [95% CI, 1.08-1.42], respectively). In contrast to Medicaid, in which there are no out-of-pocket costs, the CHIP line of business requires copays for ED visits. ED visits are influenced by maternal smoking only in the CHIP line of business (adjusted OR, 4.40; 95% CI, 1.69-11.44).

CONCLUSION

Maternal smoking increases risk for asthma diagnosis and prescription of asthma quick relief medication. Maternal smoking predicted asthma-related ED visits only for the CHIP line of business.

Public Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke

Tobacco use and tobacco smoke exposure are among the most important health threats to children, adolescents, and adults. There is no safe level of tobacco smoke exposure. The developing brains of children and adolescents are particularly vulnerable to the development of tobacco and nicotine dependence. Tobacco is unique among consumer products in that it causes disease and death when used exactly as intended. Tobacco continues to be heavily promoted to children and young adults. Flavored and alternative tobacco products, including little cigars, chewing tobacco, and electronic nicotine delivery systems are gaining popularity among youth. This statement describes important evidence-based public policy actions that, when implemented, will reduce tobacco product use and tobacco smoke exposure among youth and, by doing so, improve the health of children and young adults.

Clinical Practice Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke

Tobacco dependence starts in childhood. Tobacco exposure of children is common and causes illness and premature death in children and adults, with adverse effects starting in the womb. There is no safe level of tobacco smoke exposure. Pediatricians should screen for use of tobacco and other nicotine delivery devices and provide anticipatory guidance to prevent smoking initiation and reduce tobacco smoke exposure. Pediatricians need to be aware of the different nicotine delivery systems marketed and available.Parents and caregivers are important sources of children's tobacco smoke exposure. Because tobacco dependence is a severe addiction, to protect children's health, caregiver tobacco dependence treatment should be offered or referral for treatment should be provided (such as referral to the national smoker's quitline at 1-800-QUIT-NOW). If the source of tobacco exposure cannot be eliminated, counseling about reducing exposure to children should be provided.Health care delivery systems should facilitate the effective prevention, identification, and treatment of tobacco dependence in children and adolescents, their parents, and other caregivers. Health care facilities should protect children from tobacco smoke exposure and tobacco promotion. Tobacco dependence prevention and treatment should be part of medical education, with knowledge assessed as part of board certification examinations.

Protecting Children From Tobacco, Nicotine, and Tobacco Smoke

This technical report serves to provide the evidence base for the American Academy of Pediatrics' policy statements "Clinical Practice Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke" and "Public Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke." Tobacco use and involuntary exposure are major preventable causes of morbidity and premature mortality in adults and children. Tobacco dependence almost always starts in childhood or adolescence. Electronic nicotine delivery systems are rapidly gaining popularity among youth, and their significant harms are being documented. In utero tobacco smoke exposure, in addition to increasing the risk of preterm birth, low birth weight, stillbirth, placental abruption, and sudden infant death, has been found to increase the risk of obesity and neurodevelopmental disorders. Actions by pediatricians can help to reduce children's risk of developing tobacco dependence and reduce children's involuntary tobacco smoke exposure. Public policy actions to protect children from tobacco are essential to reduce the toll that the tobacco epidemic takes on our children.

Obesity, low levels of physical activity and smoking present opportunities for primary care asthma interventions: an analysis of baseline data from The Asthma Tools Study

BACKGROUND

Asthma prevalence, severity and outcomes are associated with various patient characteristics and lifestyle choices.

AIMS

To identify potentially modifiable factors associated with poor asthma outcomes among US primary care patients.

METHODS

Using baseline data from the Asthma Tools Study, we calculated cross-sectional frequencies of activity levels, smoking, secondhand smoke exposure and the presence of obesity, as well as rates of out-of-control asthma and asthma exacerbations. Frequencies were stratified by sex, and into three age groups: 5-11 years, 12-18 years and 19 years and older. Logistic regression was used to identify factors associated with each of the asthma outcomes.

RESULTS

In the 901 individuals enrolled in this asthma study, tobacco smoke exposure, obesity, low activity levels, poverty, inadequately controlled asthma and high asthma-related health-care utilisation were common. Across all age groups, obesity was associated with poorer asthma outcomes: either poor asthma control (odds ratio (OR)=2.3, 95% confidence interval (CI) 1.1-4.7 in 5- to 11-year-olds and OR=1.5, 95% CI 1.1-2.2 in adults) or asthma exacerbations (OR 2.9, 95% CI 1.6-5.1 in 12- to 18-year-olds and OR 1.7, 95% CI 1.1-2.5 in adults). Among adults, smoking was associated with both measures of poorer asthma outcomes; inadequate asthma control (OR=2.3, 95% CI 1.5-3.5), and asthma exacerbations (OR 1.7, 95% CI 1.1-2.6), and low physical activity were associated with poor asthma control (OR=1.5, 95% CI 1.1-2.2).

CONCLUSIONS

Obesity, low levels of physical activity and smoking are common, and they are associated with poor asthma outcomes in a sample of primary care patients, suggesting important targets for intervention.

Mindfulness, Physical Activity and Avoidance of Secondhand Smoke: A Study of College Students in Shanghai

Introduction: To better understand the documented link between mindfulness and longevity, we examine the association between mindfulness and conscious avoidance of secondhand smoke (SHS), as well as the association between mindfulness and physical activity. Method: In Shanghai University of Finance and Economics (SUFE) we surveyed a convenience sample of 1516 college freshmen. We measured mindfulness, weekly physical activity, and conscious avoidance of secondhand smoke, along with demographic and behavioral covariates. We used a multilevel logistic regression to test the association between mindfulness and conscious avoidance of secondhand smoke, and used a Tobit regression model to test the association between mindfulness and metabolic equivalent hours per week. In both models the home province of the student respondent was used as the cluster variable, and demographic and behavioral covariates, such as age, gender, smoking history, household registration status (urban vs. rural), the perceived smog frequency in their home towns, and the asthma diagnosis. Results: The logistic regression of consciously avoiding SHS shows that a higher level of mindfulness was associated with an increase in the odds ratio of conscious SHS avoidance (logged odds: 0.22, standard error: 0.07, p < 0.01). The Tobit regression shows that a higher level of mindfulness was associated with more metabolic equivalent hours per week (Tobit coefficient: 4.09, standard error: 1.13, p < 0.001). Discussion: This study is an innovative attempt to study the behavioral issue of secondhand smoke from the perspective of the potential victim, rather than the active smoker. The observed associational patterns here are consistent with previous findings that mindfulness is associated with healthier behaviors in obesity prevention and substance use. Research designs with interventions are needed to test the causal link between mindfulness and these healthy behaviors.

The economic burden of exposure to secondhand smoke for child and adult never smokers residing in U.S. public housing

OBJECTIVE

The World Health Organization (WHO) reports that nonsmokers experience disease and death due to secondhand smoke (SHS) exposure in the home. We estimated the total excess burden and costs to society due to SHS exposure in U.S. public housing.

METHODS

We quantified the public health burden for outcomes causally related to SHS exposure for nationally representative never-smoking residents in U.S. public housing using (1) WHO-recommended health outcomes and methodology, (2) publicly available and other large databases, and (3) published estimates of morbidity and mortality rates. We used published estimates of direct medical and nonmedical care costs and the value of productivity losses to estimate SHS-related societal costs for disease and death. We estimated the public health and economic burden for two serum cotinine limits of detection (LODs): 0.05 nanograms per milliliter (ng/mL) and 0.015 ng/mL.

RESULTS

In 2011, an estimated 37,791 never-smoking child and adult U.S. public housing residents experienced illness and death due to SHS exposure at home based on an LOD=0.05 ng/mL (50,967 residents at LOD=0.015 ng/mL). Costs incurred by society for these illnesses and deaths totaled $183 million (LOD=0.05 ng/mL) and $267 million (LOD=0.015 ng/mL) annually. Of the total costs, direct costs (medical and nonmedical) accounted for $128 million and $176 million for LOD=0.05 ng/mL and LOD=0.015 ng/mL, respectively. Medical care accounted for the majority of direct costs-$110 million at LOD=0.05 ng/mL and $153 million at LOD=0.015 ng/mL. Adverse respiratory health outcomes accounted for approximately one-half (56% at LOD=0.05 ng/mL and 52% at LOD=0.015 ng/mL) of total societal costs.

CONCLUSION

Implementing smoke-free policies in all U.S. public housing could save lives and decrease SHS-related morbidity and mortality in never-smoking residents, resulting in annual societal savings of $183 million at LOD=0.05 ng/mL and $267 million at LOD=0.015 ng/mL.

The lung corps' approach to reducing health disparities in respiratory disease

Health disparities are prevalent across diseases of the respiratory system, and are major sources of morbidity and mortality among disadvantaged populations in the United States. The American Thoracic Society (ATS) aims to reduce disparities that are both avoidable and unjust. In meeting this goal, the ATS is committed to creating the Lung Corps, a diverse group of senior, mid-level, and junior clinicians, trainees, researchers, and public health practitioners to help achieve health equality. This will be achieved through the following mechanisms: (1) increase awareness of health disparities; (2) empower health professionals with the knowledge and tools to address disparities; (3) shape research agendas to focus on the root causes, to identify modifiable targets, and to promote innovative approaches to reduce disparities; and (4) develop and advocate for health-related policies and regulations that improve the respiratory health of the population. To ensure success, the Lung Corps will interact with other societies, agencies, and organizations to effect elimination of disparities in respiratory health. The ATS is committed to identifying and addressing health disparities to improve the overall health of individuals affected by respiratory diseases.

Genetic ancestry influences asthma susceptibility and lung function among Latinos

BACKGROUND

Childhood asthma prevalence and morbidity varies among Latinos in the United States, with Puerto Ricans having the highest and Mexicans the lowest.

OBJECTIVE

To determine whether genetic ancestry is associated with the odds of asthma among Latinos, and secondarily whether genetic ancestry is associated with lung function among Latino children.

METHODS

We analyzed 5493 Latinos with and without asthma from 3 independent studies. For each participant, we estimated the proportion of African, European, and Native American ancestry using genome-wide data. We tested whether genetic ancestry was associated with the presence of asthma and lung function among subjects with and without asthma. Odds ratios (OR) and effect sizes were assessed for every 20% increase in each ancestry.

RESULTS

Native American ancestry was associated with lower odds of asthma (OR = 0.72, 95% CI: 0.66-0.78, P = 8.0 × 10(-15)), while African ancestry was associated with higher odds of asthma (OR = 1.40, 95% CI: 1.14-1.72, P = .001). These associations were robust to adjustment for covariates related to early life exposures, air pollution, and socioeconomic status. Among children with asthma, African ancestry was associated with lower lung function, including both pre- and post-bronchodilator measures of FEV1 (-77 ± 19 mL; P = 5.8 × 10(-5) and -83 ± 19 mL; P = 1.1 x 10(-5), respectively) and forced vital capacity (-100 ± 21 mL; P = 2.7 × 10(-6) and -107 ± 22 mL; P = 1.0 x 10(-6), respectively).

CONCLUSION

Differences in the proportions of genetic ancestry can partially explain disparities in asthma susceptibility and lung function among Latinos.

Obstructive airway disease in urban populations

PURPOSE OF REVIEW

Obstructive lung disease (OLD), including asthma and chronic obstructive pulmonary disease, has a more substantial prevalence and morbidity in urban populations. This review highlights recent publications examining the epidemiology, risk factors and interventions concerning OLD in urban populations.

RECENT FINDINGS

Using a variety of approaches, estimates of asthma prevalence in urban populations range from 5 to 25%. Early life exposures including in-utero cigarette smoke, postnatal bisphenol A, home and school particulates, and environmental air pollution contribute to increased OLD prevalence and symptom manifestations. Individuals with increased exposure to traffic-related pollution demonstrate abnormal inflammatory and lung function profiles. Obesity, more common in urban populations, is likely both a risk factor for asthma as well as contributor to poor control. Interventions targeted at home-based education and assessments are efficacious and cost-effective in improving outcomes of OLD in urban settings.

SUMMARY

The burden of OLD in urban populations is driven by maternal, environmental and acquired factors. There are few recent data regarding risk factors and interventions for urban cohorts with chronic obstructive pulmonary disease. The complex interplay of race, socioeconomic status, environmental exposures and healthcare access in the urban population requires continued research efforts.

Genome-wide association study and admixture mapping identify different asthma-associated loci in Latinos: the Genes-environments & Admixture in Latino Americans study

BACKGROUND

Asthma is a complex disease with both genetic and environmental causes. Genome-wide association studies of asthma have mostly involved European populations, and replication of positive associations has been inconsistent.

OBJECTIVE

We sought to identify asthma-associated genes in a large Latino population with genome-wide association analysis and admixture mapping.

METHODS

Latino children with asthma (n = 1893) and healthy control subjects (n = 1881) were recruited from 5 sites in the United States: Puerto Rico, New York, Chicago, Houston, and the San Francisco Bay Area. Subjects were genotyped on an Affymetrix World Array IV chip. We performed genome-wide association and admixture mapping to identify asthma-associated loci.

RESULTS

We identified a significant association between ancestry and asthma at 6p21 (lowest P value: rs2523924, P < 5 × 10(-6)). This association replicates in a meta-analysis of the EVE Asthma Consortium (P = .01). Fine mapping of the region in this study and the EVE Asthma Consortium suggests an association between PSORS1C1 and asthma. We confirmed the strong allelic association between SNPs in the 17q21 region and asthma in Latinos (IKZF3, lowest P value: rs90792, odds ratio, 0.67; 95% CI, 0.61-0.75; P = 6 × 10(-13)) and replicated associations in several genes that had previously been associated with asthma in genome-wide association studies.

CONCLUSIONS

Admixture mapping and genome-wide association are complementary techniques that provide evidence for multiple asthma-associated loci in Latinos. Admixture mapping identifies a novel locus on 6p21 that replicates in a meta-analysis of several Latino populations, whereas genome-wide association confirms the previously identified locus on 17q21.

Respiratory tract infections and asthma control in children

INTRODUCTION

Asthma control is considered the major goal of asthma management, while many determinants of control are difficult to modify. We studied the association between respiratory infection episodes (RTIs) of various types and asthma control.

METHODS

Cross-sectional data were used from children aged 4-18 years with physician-diagnosed asthma who participated in a web-based electronic portal for children with asthma, allergies or infections. Asthma control was measured using the Childhood Asthma Control Test (C-ACT) or the Asthma Control Test (ACT). Linear regression was used to analyse the association between categories of numbers of various types of RTIs sustained in the preceding 12 months (categorized) and asthma control, adjusted for potential confounders.

RESULTS

Asthma control was assessed in 654 children, and 68.5% were clinically well controlled (ACT ≥ 20). Higher total numbers of RTIs in the last 12 months were strongly associated with a lower level of asthma control (p(trend) < 0.001). Similarly strong statistically significant associations were found for subtypes of RTI: ≥4 vs. 0 otitis episodes: coefficient -1.7 (95% CI -3.3 to -0.2); ≥5 vs.0 colds: coefficient -2.3 (95% CI -3.0 to -1.6); ≥3 vs. 0 bronchitis episodes: coefficient -3.1 (95% CI -4.0 to -2.3), each with p(trend) < 0.05.

CONCLUSION

Higher numbers of reported respiratory tract infections are associated with lower level of asthma control. The different type of respiratory tract infections contribute equally to less controlled asthma.

Asthma in Hispanics. An 8-year update

This review provides an update on asthma in Hispanics, a diverse group tracing their ancestry to countries previously under Spanish rule. A marked variability in the prevalence and morbidity from asthma remains among Hispanic subgroups in the United States and Hispanic America. In the United States, Puerto Ricans and Mexican Americans have high and low burdens of asthma, respectively (the "Hispanic Paradox"). This wide divergence in asthma morbidity among Hispanic subgroups is multifactorial, likely reflecting the effects of known (secondhand tobacco smoke, air pollution, psychosocial stress, obesity, inadequate treatment) and potential (genetic variants, urbanization, vitamin D insufficiency, and eradication of parasitic infections) risk factors. Barriers to adequate asthma management in Hispanics include economic and educational disadvantages, lack of health insurance, and no access to or poor adherence with controller medications such as inhaled corticosteroids. Although considerable progress has been made in our understanding of asthma in Hispanic subgroups, many questions remain. Studies of asthma in Hispanic America should focus on environmental or lifestyle factors that are more relevant to asthma in this region (e.g., urbanization, air pollution, parasitism, and stress). In the United States, research studies should focus on risk factors that are known to or may diverge among Hispanic subgroups, including but not limited to epigenetic variation, prematurity, vitamin D level, diet, and stress. Clinical trials of culturally appropriate interventions that address multiple aspects of asthma management in Hispanic subgroups should be prioritized for funding. Ensuring high-quality healthcare for all remains a pillar of eliminating asthma disparities.

Socioeconomic status and asthma control in African American youth in SAGE II

OBJECTIVE

African Americans are disproportionately burdened by asthma. We assessed the individual and joint contribution of socioeconomic status (SES) on asthma morbidity among African American youth.

METHODS

We examined 686 African Americans (8-21 years) with asthma. To account for the joint effects of SES, a composite index was derived from maternal educational attainment, household income, and insurance status. Ordinal logistic regression was used to estimate the individual and joint effect of SES on asthma control. Models were adjusted for age, sex, controller medication use, in utero smoke exposure, family history of asthma, family history of rhinitis, breastfeeding, daycare attendance, and mold exposure.

RESULTS

Participants were classified as Poorly Controlled Asthma (40.8%), Partially Controlled Asthma (29.7%), or Controlled Asthma (30.2%). Of the individual SES indicators, low income was the strongest predictor of poor asthma control. Children with low income had worse asthma control than those with higher income (OR 1.39; 95% CI 0.92-2.12). The SES index ranged from 4-9. SES was associated with 17% increased odds of poor asthma control with each decrease in the index (95% CI 1.05-1.32). The SES index was associated with asthma-related symptoms, nocturnal awakenings, limited activity, and missed school days.

CONCLUSIONS

The negative effects of SES were observed along the entire socioeconomic gradient, and the adverse asthma outcomes observed in African American youth were not limited to the very poor. We also found that the SES index may be a more consistent and useful predictor of poor asthma outcomes than each indicator alone.

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

RATIONALE

The burden of asthma is highest among socioeconomically disadvantaged populations; however, its impact is differentially distributed among racial and ethnic groups.

OBJECTIVES

To assess the collective effect of maternal educational attainment, annual household income, and insurance type on childhood asthma among minority, urban youth.

METHODS

We included Mexican American (n = 485), other Latino (n = 217), and African American (n = 1,141) children (aged 8-21 yr) with and without asthma from the San Francisco Bay Area. An index was derived from maternal educational attainment, annual household income, and insurance type to assess the collective effect of socioeconomic status on predicting asthma. Logistic regression stratified by racial and ethnic group was used to estimate adjusted odds ratios (aOR) and their 95% confidence intervals (CI). We further examined whether acculturation explained the socioeconomic-asthma association in our Latino population.

MEASUREMENTS AND MAIN RESULTS

In the adjusted analyses, African American children had 23% greater odds of asthma with each decrease in the socioeconomic index (aOR, 1.23; 95% CI, 1.09-1.38). Conversely, Mexican American children have 17% reduced odds of asthma with each decrease in the socioeconomic index (aOR, 0.83; 95% CI, 0.72-0.96) and this relationship was not fully explained by acculturation. This association was not observed in the other Latino group.

CONCLUSIONS

Socioeconomic status plays an important role in predicting asthma, but has different effects depending on race and ethnicity. Further steps are necessary to better understand the risk factors through which socioeconomic status could operate in these populations to prevent asthma.

A twin study of early-childhood asthma in Puerto Ricans

BACKGROUND

The relative contributions of genetics and environment to asthma in Hispanics or to asthma in children younger than 3 years are not well understood.

OBJECTIVE

To examine the relative contributions of genetics and environment to early-childhood asthma by performing a longitudinal twin study of asthma in Puerto Rican children ≤ 3 years old.

METHODS

678 twin infants from the Puerto Rico Neo-Natal Twin Registry were assessed for asthma at age 1 year, with follow-up data obtained for 624 twins at age 3 years. Zygosity was determined by DNA microsatellite profiling. Structural equation modeling was performed for three phenotypes at ages 1 and 3 years: physician-diagnosed asthma, asthma medication use in the past year, and ≥ 1 hospitalization for asthma in the past year. Models were additionally adjusted for early-life environmental tobacco smoke exposure, sex, and age.

RESULTS

The prevalences of physician-diagnosed asthma, asthma medication use, and hospitalization for asthma were 11.6%, 10.8%, 4.9% at age 1 year, and 34.1%, 40.1%, and 8.5% at 3 years, respectively. Shared environmental effects contributed to the majority of variance in susceptibility to physician-diagnosed asthma and asthma medication use in the first year of life (84%-86%), while genetic effects drove variance in all phenotypes (45%-65%) at age 3 years. Early-life environmental tobacco smoke, sex, and age contributed to variance in susceptibility.

CONCLUSION

Our longitudinal study in Puerto Rican twins demonstrates a changing contribution of shared environmental effects to liability for physician-diagnosed asthma and asthma medication use between ages 1 and 3 years. Early-life environmental tobacco smoke reduction could markedly reduce asthma morbidity in young Puerto Rican children.

Childhood obesity and asthma control in the GALA II and SAGE II studies

RATIONALE

Obesity is associated with increased asthma morbidity, lower drug responsiveness to inhaled corticosteroids, and worse asthma control. However, most prior investigations on obesity and asthma control have not focused on pediatric populations, considered environmental exposures, or included minority children.

OBJECTIVES

To examine the association between body mass index categories and asthma control among boys and girls; and whether these associations are modified by age and race/ethnicity.

METHODS

Children and adolescents ages 8-19 years (n = 2,174) with asthma were recruited from the Genes-environments and Admixture in Latino Americans (GALA II) Study and the Study of African Americans, Asthma, Genes, and Environments (SAGE II). Ordinal logistic regression was used to estimate odds ratios (OR) and their confidence intervals (95% CI) for worse asthma control.

MEASUREMENTS AND MAIN RESULTS

In adjusted analyses, boys who were obese had a 33% greater chance of having worse asthma control than their normal-weight counterparts (OR, 1.33; 95% CI, 1.04-1.71). However, for girls this association varied with race and ethnicity (P interaction = 0.008). When compared with their normal-weight counterparts, obese African American girls (OR, 0.65; 95% CI, 0.41-1.05) were more likely to have better controlled asthma, whereas Mexican American girls had a 1.91 (95% CI, 1.12-3.28) greater odds of worse asthma control.

CONCLUSIONS

Worse asthma control is uniformly associated with increased body mass index in boys. Among girls, the direction of this association varied with race/ethnicity.

Epigenetic mechanisms and the development of asthma

Asthma is heritable, influenced by the environment, and modified by in utero exposures and aging; all of these features are also common to epigenetic regulation. Furthermore, the transcription factors that are involved in the development of mature T cells that are critical to the T(H)2 immune phenotype in asthmatic patients are regulated by epigenetic mechanisms. Epigenetic marks (DNA methylation, modifications of histone tails, and noncoding RNAs) work in concert with other components of the cellular regulatory machinery to control the spatial and temporal levels of expressed genes. Technology to measure epigenetic marks on a genomic scale and comprehensive approaches to data analysis have recently emerged and continue to improve. Alterations in epigenetic marks have been associated with exposures relevant to asthma, particularly air pollution and tobacco smoke, as well as asthma phenotypes, in a few population-based studies. On the other hand, animal studies have begun to decipher the role of epigenetic regulation of gene expression associated with the development of allergic airway disease. Epigenetic mechanisms represent a promising line of inquiry that might, in part, explain the inheritance and immunobiology of asthma.

Advances in pediatric asthma in 2012: moving toward asthma prevention

Last year's "Advances in pediatric asthma: moving forward" concluded the following: "Now is also the time to utilize information recorded in electronic medical records to develop innovative disease management plans that will track asthma over time and enable timely decisions on interventions in order to maintain control that can lead to disease remission and prevention." This year's summary will focus on recent advances in pediatric asthma on modifying disease activity, preventing asthma exacerbations, managing severe asthma, and risk factors for predicting and managing early asthma, as indicated in Journal of Allergy and Clinical Immunology publications in 2012. Recent reports continue to shed light on methods to improve asthma management through steps to assess disease activity, tools to standardize outcome measures in asthma, genetic markers that predict risk for asthma and appropriate treatment, and interventions that alter the early presentation of asthma to prevent progression. We are well on our way to creating a pathway around wellness in asthma care and also to use new tools to predict the risk for asthma and take steps to not only prevent asthma exacerbations but also to prevent the early manifestations of the disease and thus prevent its evolution to severe asthma.

Asthma Research for All of the United States

Asthma disproportionally affects different ethnic/racial groups, with Puerto Ricans and African Americans suffering the highest asthma prevalence and morbidity, Mexicans the lowest, and non-Hispanic whites in between. Genome-wide association studies of asthma have found both shared and race/ethnic-specific genetic risks factors for asthma. However, the majority of genetic asthma research is performed in populations of European descent, which limits the benefits of genetic research to European populations. It is important to biomedical and clinical research to include more diverse and underrepresented populations. The rich genetic diversity of all populations can be leveraged to scientific advantage. For example, admixture mapping provides a more powerful approach than traditional genome-wide allelic association studies in discovering genetic associations for complex diseases. By being more inclusive we can achieve a better understanding of the genetics of asthma, address health disparities, and ensure that scientific advances will benefit populations worldwide.