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.

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.

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).

Genome-wide association study of inhaled corticosteroid response in admixed children with asthma.

Background: Inhaled corticosteroids (ICS) are the most widely prescribed and effective medication to control asthma symptoms and exacerbations. However, many children still have asthma exacerbations despite treatment, particularly in admixed populations, such as Puerto Ricans and African Americans. A few genome-wide association studies (GWAS) have been performed in European and Asian populations, and they have demonstrated the importance of the genetic component in ICS response.

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.

A genome-wide association and admixture mapping study of bronchodilator drug response in African Americans with asthma.

Short-acting β-adrenergic receptor agonists (SABAs) are the most commonly prescribed asthma medications worldwide. Response to SABAs is measured as bronchodilator drug response (BDR), which varies among racial/ethnic groups in the United States. However, the genetic variation that contributes to BDR is largely undefined in African Americans with asthma.

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.

Genetic Determinants of Telomere Length in African American Youth.

Telomere length (TL) is associated with numerous disease states and is affected by genetic and environmental factors. However, TL has been mostly studied in adult populations of European or Asian ancestry. These studies have identified 34 TL-associated genetic variants recently used as genetic proxies for TL.

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.

Whole-Genome Sequencing of Pharmacogenetic Drug Response in Racially Diverse Children with Asthma.

Rationale: Albuterol, a bronchodilator medication, is the first-line therapy for asthma worldwide. There are significant racial/ethnic differences in albuterol drug response.

Objectives: To identify genetic variants important for bronchodilator drug response (BDR) in racially diverse children.

Identification of a novel locus associated with skin colour in African-admixed populations.

Skin pigmentation is a complex trait that varies largely among populations. Most genome-wide association studies of this trait have been performed in Europeans and Asians. We aimed to uncover genes influencing skin colour in African-admixed individuals.

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.

Breastfeeding associated with higher lung function in African American youths with asthma.

Objective: In the United States, Puerto Ricans and African Americans have lower prevalence of breastfeeding and worse clinical outcomes for asthma compared with other racial/ethnic groups. We hypothesize that the history of breastfeeding is associated with increased forced expiratory volume in 1 second (FEV) % predicted and reduced asthma exacerbations in Latino and African American youths with asthma.

Methods: As part of the Genes-environments & Admixture in Latino Americans (GALA II) Study and the Study of African Americans, asthma, Genes & Environments (SAGE II), we conducted case-only analyses in children and adolescents aged 8-21 years with asthma from four different racial/ethnic groups: African Americans (n = 426), Mexican Americans (n = 424), mixed/other Latinos (n = 255), and Puerto Ricans (n = 629).

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.

The Effects of Migration and Assortative Mating on Admixture Linkage Disequilibrium.

Statistical models in medical and population genetics typically assume that individuals assort randomly in a population. While this simplifies model complexity, it contradicts an increasing body of evidence of nonrandom mating in human populations. Specifically, it has been shown that assortative mating is significantly affected by genomic ancestry.

Air Pollution and Lung Function in Minority Youth with Asthma in the GALA II (Genes-Environments and Admixture in Latino Americans) and SAGE II (Study of African Americans, Asthma, Genes, and Environments) Studies.

Rationale: Adverse effects of exposures to ambient air pollution on lung function are well documented, but evidence in racial/ethnic minority children is lacking.

Objectives: To assess the relationship between air pollution and lung function in minority children with asthma and possible modification by global genetic ancestry.

Methods: The study population consisted of 1,449 Latino and 519 African American children with asthma from five different geographical regions in the mainland United States and Puerto Rico.

Obesity and bronchodilator response in black and Hispanic children and adolescents with asthma.

Background: Obesity is associated with poor asthma control, increased asthma morbidity, and decreased response to inhaled corticosteroids. We hypothesized that obesity would be associated with decreased bronchodilator responsiveness in children and adolescents with asthma. In addition, we hypothesized that subjects who were obese and unresponsive to bronchodilator would have worse asthma control and would require more asthma controller medications.

Genome-wide association study and admixture mapping reveal new loci associated with total IgE levels in Latinos.

Background: IgE is a key mediator of allergic inflammation, and its levels are frequently increased in patients with allergic disorders.

Objective: We sought to identify genetic variants associated with IgE levels in Latinos.

Methods: We performed a genome-wide association study and admixture mapping of total IgE levels in 3334 Latinos from the Genes-environments & Admixture in Latino Americans (GALA II) study.

Whole-genome sequencing of individuals from a founder population identifies candidate genes for asthma.

Asthma is a complex genetic disease caused by a combination of genetic and environmental risk factors. We sought to test classes of genetic variants largely missed by genome-wide association studies (GWAS), including copy number variants (CNVs) and low-frequency variants, by performing whole-genome sequencing (WGS) on 16 individuals from asthma-enriched and asthma-depleted families. The samples were obtained from an extended 13-generation Hutterite pedigree with reduced genetic heterogeneity due to a small founding gene pool and reduced environmental heterogeneity as a result of a communal lifestyle.

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.

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.

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.