Associations of acculturation and country of birth with asthma and wheezing in Mexican American youths

Disaggregating Latino nativity in equity research using electronic health records

OBJECTIVE

To develop and validate prediction models for inference of Latino nativity to advance health equity research.

DATA SOURCES/STUDY SETTING

This study used electronic health records (EHRs) from 19,985 Latino children with self-reported country of birth seeking care from January 1, 2012 to December 31, 2018 at 456 community health centers (CHCs) across 15 states along with census-tract geocoded neighborhood composition and surname data.

STUDY DESIGN

We constructed and evaluated the performance of prediction models within a broad machine learning framework (Super Learner) for the estimation of Latino nativity. Outcomes included binary indicators denoting nativity (US vs. foreign-born) and Latino country of birth (Mexican, Cuban, Guatemalan). The performance of these models was compared using the area under the receiver operating characteristics curve (AUC) from an externally withheld patient sample.

DATA COLLECTION/EXTRACTION METHODS

Census surname lists, census neighborhood composition, and Forebears administrative data were linked to EHR data.

PRINCIPAL FINDINGS

Of the 19,985 Latino patients, 10.7% reported a non-US country of birth (5.1% Mexican, 4.7% Guatemalan, 0.8% Cuban). Overall, prediction models for nativity showed outstanding performance with external validation (US-born vs. foreign: AUC = 0.90; Mexican vs. non-Mexican: AUC = 0.89; Guatemalan vs. non-Guatemalan: AUC = 0.95; Cuban vs. non-Cuban: AUC = 0.99).

CONCLUSIONS

Among challenges facing health equity researchers in health services is the absence of methods for data disaggregation, and the specific ability to determine Latino country of birth (nativity) to inform disparities. Recent interest in more robust health equity research has called attention to the importance of data disaggregation. In a multistate network of CHCs using multilevel inputs from EHR data linked to surname and community data, we developed and validated novel prediction models for the use of available EHR data to infer Latino nativity for health disparities research in primary care and health services research, which is a significant potential methodologic advance in studying this population.

Biomarkers of organophosphate insecticides exposure and asthma in general US adults: findings from NHANES 1999-2018 data

The limited evidence linking exposure to organophosphate insecticides (OPIs) and asthma in the general population prompted us to investigate this association. Our study focused on US adults and utilized representative samples from the National Health and Nutrition Examination Survey (NHANES). From the 7 NHANES waves (1999-2018), we detected OPIs exposure using the urinary concentrations of six metabolites of dialkyl phosphates (DAPs). To evaluate the relationship between these OPIs and asthma, we employed three statistical methods: survey-multivariable logistic regression (SMLR), generalized weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR). Stratified analyses were done based on the relevant variable subgroups, and sensitivity analyses were carried out to evaluate the robustness of findings. A total of 6009 adults aged from 20 to 85 years old, representing the 313.5 million adults in the non-institutionalized US population, were included in our analyses. Among them, 842 participants were determined as asthma patients with an age-adjusted prevalence of 14.2%. Our results showed that dimethyl phosphate (DMP) (adjusted odd ratio (AOR) = 1.471, 95% CI: 1.086, 1.993), diethyl phosphate (DEP) (AOR = 1.453, 95% CI: 1.118, 1.888), dimethyl thiophosphate (DMTP) (AOR = 1.454, 95% CI: 1.071, 1.973), and dimethyl dithiophosphate (DMDTP) (AOR = 1.478, 95% CI: 1.119, 1.953) had a positive correlation with asthma in adults. This association was stronger in females, non-Hispanic White populations and those with a small amount of physical activity. Our study findings indicated that exposure to OPIs may elevate the risk of asthma in US general adults. Specifically, females, individuals from non-Hispanic White backgrounds, and those with lower levels of physical activity are more susceptible to developing asthma when exposed to OPIs.

Heterogeneity of Asthma Care Among Hispanic Subgroups: Lower Utilization of Hospital-based Care among Spanish-speaking Hispanics

BACKGROUND

Studies found heterogeneity of asthma prevalence among Hispanic subgroups using survey data but addressed under-diagnosis issues due to limited access to health care and diagnosis bias.

OBJECTIVES

To examine heterogeneity by language in health care utilization for asthma among Hispanic subgroups.

RESEARCH DESIGN

A retrospective, longitudinal cohort study of Medi-Cal claims data (2018-2019) using logistic regression to estimate the odds ratio of health care utilization for asthma.

SUBJECTS

In all, 12,056 (ages 5-64) Hispanics living in Los Angeles were identified as having persistent asthma.

MEASURES

Primary language is the predictor variable and outcome measures include ED visits, hospitalizations, and outpatient visits.

RESULTS

The odds of ED visits among Spanish-speaking Hispanics were lower than English-speaking Hispanics in the subsequent 6 (95% CI=0.65-0.93) and 12 (95% CI=0.66-0.87) months. Spanish-speaking Hispanics were less likely than their English-speaking counterparts to utilize hospitalization in the 6 months (95% CI=0.48-0.98), while they were more likely to utilize outpatient care (95% CI=1.04-1.24). For Hispanics of Mexican origin, the odds of ED visits among Spanish-speaking Hispanics were also lower in the 6 and 12 months (95% CI=0.63-0.93, 95% CI=0.62-0.83), but their odds of outpatient visits were higher for outpatient visits in the 6 months (95% CI=1.04-1.26).

CONCLUSIONS

Spanish-speaking Hispanics with persistent asthma were less likely than English-speaking Hispanics to utilize ED visits and hospitalizations but were more likely to utilize outpatient visits. The findings suggest the reduced burden of asthma among the Spanish-speaking Hispanic subgroup and contribute to explaining the protection effect, specifically among Spanish-speaking Hispanics living in highly segregated communities.

Asthma Ambulatory Care Quality in Foreign-Born Latino Children in the United States

BACKGROUND

Foreign-born Latino children in the United States (US) have poor asthma outcomes, but the role of routine care utilization in these outcomes is unclear. Our objective was to compare select ambulatory care utilization measures for asthma between foreign-born Latino, US-born Latino, and non-Hispanic white children.

METHODS

Using a multistate network of clinics with a linked electronic health record, we compared the International Classification of Disease (ICD)-coded asthma diagnosis among those with respiratory symptoms, electronic health records documentation of diagnosis, prescriptions, and influenza vaccination of foreign-born and US-born Latino children, and non-Hispanic white children over a 10+ year study period. We also examined outcomes by country of birth in children from Mexico, Cuba, and Guatemala.

RESULTS

Among our study population (n = 155,902), 134,570 were non-Hispanic white, 19,143 were US-born Latino, and 2189 were foreign-born Latino. Among those with suspicious respiratory symptoms, there was no difference between these groups in the predicted probability of an ICD-coded asthma diagnosis. US-born Latino children with asthma were less likely to have asthma documented on their problem list, more likely to have an albuterol prescription, and less likely to have an inhaled steroid prescribed. All Latino children had higher rates of influenza vaccination than non-Hispanic white children.

CONCLUSIONS

In a national network, there were few disparities between Latino (US- and foreign-born) children and non-Hispanic white comparators in many common asthma care services, except some measures in US-born Latino children. Providers should understand that their US-born Latino children may be at elevated risk for not receiving adequate asthma care.

Latino-white disparities in ICD-coded asthma diagnosis among US children

INTRODUCTION

It is uncertain if disparities in asthma diagnosis between Latino and non-Hispanic white children stem from differences in diagnosis over time among children presenting with similar clinical scenarios suggestive of asthma.

METHODS

We evaluated the odds of International Classification of Disease (ICD)-coded asthma diagnosis in Latino (English and Spanish preferring) and non-Hispanic white children, overall (N = 524,456) and among those presenting with possible asthma indicators (N = 85,516) over a 13-year period, using electronic health record data from a multi-state network of community health centers.

RESULTS

Among those with possible asthma indicators, Spanish-preferring Latinos had lower adjusted odds of ICD-coded asthma diagnosis compared to non-Hispanic whites (OR = 0.87, 95%CI = 0.77-0.99); English-preferring Latinos did not differ from non-Hispanic whites. Differences in ICD-coded diagnosis between ethnicity/language groups varied by presenting symptom.

CONCLUSIONS

Spanish-preferring Latino children may be less-likely to have ICD-coded asthma documented in the EHR when presenting with certain clinical indicators suggestive of asthma. Clinicians should be cognizant of the need for the follow-up of these indicators in Spanish-preferring Latino children.

Exploring factors associated with health disparities in asthma and poorly controlled asthma among school-aged children in the U.S

Objective: Certain populations suffer disproportionately from asthma and asthma morbidity. The objective was to provide a national descriptive profile of asthma control and treatment patterns among school-aged children (SAC: aged 6-17) in the U.S. Methods: This was a cross-sectional analysis using the nationally representative 2007-2014 Medical Expenditure Panel Survey. Among SAC with asthma, indicators of poor control included: exacerbation/asthma attack; >3 canisters short-acting beta agonist (SABA)/3 months; and asthma-specific Emergency Department or inpatient visits (ED/IP). Results: Non-Hispanic black, non-Hispanic multiple races, Puerto Rican, obese, Medicaid, poor, ≥2 non-asthma chronic comorbidities (CC), and family average CC ≥ 2 were associated with higher odds of having asthma. The following had significantly higher odds ratios (OR) of excessive SABA use compared to non-Hispanic whites [OR; CI; p < 0.05]: Puerto Rican (3.8; 2.1-6.9), Mexican (3.6; 2.0-6.4), Central/South American (3.0; 1.2-7.7), Hispanic-other (3.1; 1.1-9.0), non-Hispanic black (2.5; 1.6-3.9), and non-Hispanic Asian (4.0; 1.7-9.2). SABA OR were also significant for Spanish spoken at home (2.5; 1.6-3.8), obese (2.1; 1.3-3.3), Medicaid (2.9; 2.0-4.1), no medical insurance (2.1; 1.1-4.1), no prescription insurance (2.5; 1.8-3.5), poor (2.8; 1.7-4.7), CC ≥ 2 (2.1; 1.6-2.8), parent-without high-school degree (2.5; 1.8-3.6), parent-SF-12 Physical Component Scale <50 (1.6; 1.2-2.1) and Mental Component Scale <50 (1.5; 1.1-2.0). Significant differences also existed across subgroups for ED/IP visits. Conclusions: There are disparities in asthma control and prevalence among certain populations in the U.S. These results provide national data on disparities in several indicators of poor asthma control beyond the standard race/ethnicity groupings.

Associations of urban greenness with asthma and respiratory symptoms in Mexican American children

BACKGROUND

Evidence on the association between residential surrounding greenness (RSG) in urban areas with asthma and asthma symptoms is inconsistent.

OBJECTIVE

To examine the association of RSG with respiratory outcomes in a sample of Mexican American children living in inner-city Chicago, Illinois.

METHODS

This study is based on parent-reported data on 1915 Mexican American children. We calculated RSG using the normalized difference vegetation index based on satellite imagery within buffers of 100, 250, and 500 m of each child's residence. Multivariable multilevel mixed-effect logistic regression was used to estimate adjusted odds ratios (aORs) for the effect of a 1-interquartile range increase in greenness.

RESULTS

In adjusted analyses, a protective effect of greenness within 100 m was observed for lifetime wheezing (aOR, 0.82; 95% CI, 0.69-0.96). Environmental tobacco smoke (ETS) exposure modified the association of RSG with lifetime asthma and current dry cough at night. For all buffer distances, increased greenness was associated with lower odds of lifetime asthma among children with current ETS exposure (100 m: aOR, 0.43; 95% CI, 0.22-0.87; 250 m: aOR, 0.39; 95% CI, 0.18-0.84; 500 m: aOR, 0.48; 95% CI, 0.26-0.90) and lower odds of current dry cough at night among children with perinatal ETS exposure (100 m: aOR, 0.53; 95% CI, 0.31-0.92; 250 m: aOR, 0.55; 95% CI, 0.31-0.98; 500 m: aOR, 0.55; 95% CI, 0.35-0.87).

CONCLUSION

Our results suggest inverse associations of urban greenness with respiratory outcomes, especially in children exposed to ETS. Further research is needed to examine the mechanisms through which RSG may be associated with the risk of asthma and contribute to health.

An Examination of the Association of Multiple Acculturation Measures with Asthma Status Among Elementary School Students in El Paso, Texas

Some researchers posit that the lower prevalence of asthma among those of Mexican descent may result from an under-diagnosis and recommend a critical appraisal of factors related to race/ethnicity, like acculturation, and its influence on asthma status. Survey data were analyzed using multinomial logistic regression to examine the association of child's asthma status (no wheezing/no asthma symptoms, possible undiagnosed and diagnosed asthma) with measures of acculturation among Hispanic students (n = 1095). In this population, the prevalence of diagnosed asthma (15%) was higher than both national (7.6%) and state (6.8%) averages for Hispanic children in 2012. While bivariate analyses showed significant associations for asthma status and measures of acculturation, multivariate analyses did not. There is an underestimated burden of illness among Hispanic children in El Paso County. More research on the suitability of acculturation constructs is needed to delineate what they actually measure and how acculturation influences asthma status.

Country of Birth and Variations in Asthma and Wheezing Prevalence, and Emergency Department Utilization in Children: A NHANES Study

Asthma prevalence and asthma-related healthcare utilization differ across racial/ethnic groups and geographical areas. This study builds on previous research to examine the relationship between country of birth and asthma prevalence and healthcare utilization using a national data set. The National Health and Nutrition Examination Survey (NHANES) Demographic and Questionnaire Files from 2007 to 2012 were used for this study. We used SPSS complex sampling design to estimate the association between country of birth and asthma prevalence, wheezing and emergency department (ED) use. The sample size was 8272 children and adolescents between the ages of 5 and 19 years old. US-born children had more reported episodes of wheezing (p = 0.024) 95 % CI 1.06; 2.54. There was no association between country of birth and asthma and ED use. US-born children and adolescents compared to foreign-born children and adolescents are more likely to have episodes of wheezing.

Respiratory Health in Migrant Populations: A Crisis Overlooked

The crisis in the Middle East has raised awareness about the challenges encountered by migrant populations, in particular, health-care access and delivery. Similar challenges are encountered by migrant populations around the world, including those entering the United States as refugees and/or survivors of torture as well as Mexicans and other Latin Americans crossing the border. During the 2016 International American Thoracic Society Meeting held in San Francisco, California, a group of researchers and health-care providers discussed these challenges at a minisymposium devoted to the respiratory health of migrants. The discussion focused on the increased incidence of airway diseases among individuals migrating to more developed countries, the problems created by sleep disorders and their implications for cardiovascular and mental health, the challenges inherent in the control of infections in refugee populations, and the problems resulting from deportation. The group also discussed the potential impact of novel strategies made available by Internet-based technologies and how these strategies could be deployed to support worldwide efforts in assisting migrants and refugees, even in countries that find themselves in the direst circumstances. These presentations are summarized in this document, which is not meant to be exhaustive, but to improve awareness about the challenges confronted by migrants and their host nations regarding respiratory health-care access and delivery, and about the need for adequate investment of resources to better define these challenges through research and for the development of efficient strategies for intervention.

Prevalence of Asthma in School Children on the Arizona-Sonora Border

BACKGROUND

Mexican-born children living in the United States have a lower prevalence of asthma than other US children. Although children of Mexican descent near the Arizona (AZ)-Sonora border are genetically similar, differences in environmental exposures might result in differences in asthma prevalence across this region.

OBJECTIVE

The objective of this study was to determine if the prevalence of asthma and wheeze in these children varies across the AZ-Sonora border.

METHODS

The International Study of Asthma and Allergy in Children written and video questionnaires were administered to 1753 adolescents from 5 middle schools: Tucson (school A), Nogales, AZ (schools B, C), and Nogales, Sonora, Mexico (schools D, E). The prevalence of asthma and symptoms was compared, with analyses in the AZ schools limited to self-identified Mexican American students.

RESULTS

Compared with the Sonoran reference school E, the adjusted odds ratio (OR) for asthma was significantly higher in US schools A (OR 4.89, 95% confidence interval [CI] 2.72-8.80), B (OR 3.47, 95% CI 1.88-6.42), and C (OR 4.12, 95% CI 1.78-9.60). The adjusted OR for wheeze in the past year was significantly higher in schools A (OR 2.19, 95% CI 1.20-4.01) and B (OR 2.67, 95% CI 1.42-5.01) on the written questionnaire and significantly higher in A (OR 2.13, 95% CI 1.22-3.75), B (OR 1.95, 95% CI 1.07-3.53), and Sonoran school D (OR 2.34, 95% CI 1.28-4.30) on the video questionnaire compared with school E.

CONCLUSIONS

Asthma and wheeze prevalence differed significantly between schools and was higher in the United States. Environmental factors that may account for these differences could provide insight into mechanisms of protection from asthma.

Association of neighborhood crime with asthma and asthma morbidity among Mexican American children in Chicago, Illinois

BACKGROUND

There is increasing evidence that neighborhood-level factors, in addition to individual-level factors, may contribute directly or indirectly to childhood asthma by affecting environmental and lifestyle factors. Exposure to neighborhood crime and violence has been associated with poor health outcomes, especially among underserved and minority populations, and its effect on respiratory health is an area of active research.

OBJECTIVE

To examine the association of residential neighborhood crime with asthma and asthma-related outcomes among Mexican American children.

METHODS

This cross-sectional study was conducted with parents of 2,023 Mexican American children. We derived measures of neighborhood (census tract) violent, property, and drug abuse crime and used multilevel generalized estimating equations to test associations of neighborhood crime counts with respiratory conditions.

RESULTS

In multiple regression models, a 1-SD increase in neighborhood property crimes significantly increased the odds of lifetime asthma, lifetime wheezing, lifetime emergency department (ED) visits attributable to asthma or wheezing, and lifetime hospitalization attributable to asthma or wheezing by 25%, 18%, 44%, and 62%, respectively. A 1-SD elevation in neighborhood violent crime was positively and significantly associated with 21% and 57% higher odds of lifetime wheezing and ED visits, respectively. We also observed 13% and 44% significantly increased odds of lifetime wheezing and ED visits, respectively, for a 1-SD increase in drug abuse crime. These findings were not explained or modified by individual- and neighborhood-level covariates.

CONCLUSION

Higher neighborhood crime was associated with greater odds of asthma and asthma morbidity in Mexican American children.

Contributions of individual acculturation and neighborhood ethnic density to variations in Hispanic children's respiratory health in a US-Mexican border metropolis

BACKGROUND

We used an expanded conceptualization of ethnic density at the neighborhood level, tailored to Hispanic majority communities in the USA, and a robust measure of children's acculturation at the individual level, to predict Hispanic children's respiratory health.

METHODS

We conducted a cross-sectional survey of 1904 children in 2012 in El Paso, TX, USA. One thousand one hundred and seven Hispanic children nested within 72 census tracts were analyzed. Multilevel logistic regression models with cross-level interactions were used to predict bronchitis, asthma and wheezing during sleep.

RESULTS

A neighborhood-level ethnic density factor was a non-significant risk factor while individual-level acculturation was a significant risk factor for the three outcomes. Pest troubles and not having been breastfed as an infant intensified the positive association between ethnic density and bronchitis. Increases in ethnic density intensified the odds of wheezing in sleep if the child was not low birth weight or was not economically deprived.

CONCLUSIONS

Results suggest that increasing individual-level acculturation is detrimental for US Hispanic children's respiratory health in this Hispanic majority setting, while high ethnic density neighborhoods are mildly risky and pose more significant threats when other individual-level factors are present.

Pulmonary Disease and Age at Immigration among Hispanics. Results from the Hispanic Community Health Study/Study of Latinos

RATIONALE

Asthma has been reported to be more prevalent among Hispanics of Puerto Rican heritage than among other Hispanics and among Hispanics born in the United States or who immigrated as children than among those who came as adults; however, direct comparisons across Hispanic groups are lacking.

OBJECTIVES

To test whether asthma is more prevalent among Hispanics of Puerto Rican heritage than among other Hispanic groups, whether asthma is associated with age of immigration, and whether chronic obstructive pulmonary disease varies by heritage in a large, population-based cohort of Hispanics in the United States.

METHODS

The Hispanic Community Health Study/Study of Latinos researchers recruited a population-based probability sample of 16,415 Hispanics/Latinos, 18-74 years of age, in New York City, Chicago, Miami, and San Diego. Participants self-reported Puerto Rican, Cuban, Dominican, Mexican, Central American, or South American heritage; birthplace; and, if relevant, age at immigration. A respiratory questionnaire and standardized spirometry were performed with post-bronchodilator measures for those with airflow limitation.

MEASUREMENTS AND MAIN RESULTS

The prevalence of physician-diagnosed asthma among Puerto Ricans (36.5%; 95% confidence interval, 33.6-39.5%) was higher than among other Hispanics (odds ratio, 3.9; 95% confidence interval, 3.3-4.6). Hispanics who were born in the mainland United States or had immigrated as children had a higher asthma prevalence than those who had immigrated as adults (19.6, 19.4, and 14.1%, respectively; P < 0.001). Current asthma, bronchodilator responsiveness, and wheeze followed similar patterns. Chronic obstructive pulmonary disease prevalence was higher among Puerto Ricans (14.1%) and Cubans (9.8%) than among other Hispanics (<6.0%), but it did not vary across Hispanic heritages after adjustment for smoking and prior asthma (P = 0.22), by country of birth, or by age at immigration.

CONCLUSIONS

Asthma was more prevalent among Puerto Ricans, other Hispanics born in the United States, and those who had immigrated as children than among other Hispanics. In contrast, the higher prevalence of chronic obstructive pulmonary disease among Puerto Ricans and Cubans was largely reflective of differential smoking patterns and asthma.

In utero exposure to pets is associated with asthma and wheezing in Mexican American children

OBJECTIVE

To examine the associations of in utero and early life exposure to cats/dogs and birds with the risk of lifetime doctor-diagnosed asthma and other respiratory conditions in a sample of Mexican American (MA) children 4-18 years of age.

METHODS

This study is a population-based cross-sectional investigation of 1816 MA children. We conducted multiple logistic models examining the relationship of asthma and wheezing with exposures to cats/dogs and birds in utero, infancy and at the time of the survey adjusted for country of birth, family history of asthma/allergies, antibiotics use in infancy and other covariates.

RESULTS

In adjusted analyses, in utero exposure to cats/dogs and birds jointly was associated with increased odds of asthma (adjusted odds ratio (aOR): 2.89; 95% confidence interval (CI): 1.34-6.23), ever wheezing (aOR: 1.96; 95% CI: 1.11-3.46) and current exercise-induced wheezing (aOR: 3.16; 95% CI: 1.27-7.85) compared to children not exposed to these pets in utero. Children who were exposed to both cats/dogs and birds in utero had an elevated, albeit statistically non-significant, odds of current wheezing. Exposures in infancy and at the time of the survey to cats/dogs and birds were not associated with asthma or wheezing.

CONCLUSIONS

In utero exposure to pets might be associated with an increased risk of asthma and respiratory conditions in a sample of non-affluent MA children.

Genetic Ancestry and Asthma and Rhinitis Occurrence in Hispanic Children: Findings from the Southern California Children's Health Study

Background

Asthma and rhinitis are common childhood health conditions. Being an understudied and rapidly growing population in the US, Hispanic children have a varying risk for these conditions that may result from sociocultural (including acculturative factors), exposure and genetic diversities. Hispanic populations have varying contributions from European, Amerindian and African ancestries. While previous literature separately reported associations between genetic ancestry and acculturation factors with asthma, whether Amerindian ancestry and acculturative factors have independent associations with development of early-life asthma and rhinitis in Hispanic children remains unknown. We hypothesized that genetic ancestry is an important determinant of early-life asthma and rhinitis occurrence in Hispanic children independent of sociodemographic, acculturation and environmental factors.

Methods

Subjects were Hispanic children (5–7 years) who participated in the southern California Children’s Health Study. Data from birth certificates and questionnaire provided information on acculturation, sociodemographic and environmental factors. Genetic ancestries (Amerindian, European, African and Asian) were estimated based on 233 ancestry informative markers. Asthma was defined by parental report of doctor-diagnosed asthma. Rhinitis was defined by parental report of a history of chronic sneezing or runny or blocked nose without a cold or flu. Sample sizes were 1,719 and 1,788 for investigating the role of genetic ancestry on asthma and rhinitis, respectively.

Results

Children had major contributions from Amerindian and European ancestries. After accounting for potential confounders, per 25% increase in Amerindian ancestry was associated with 17.6% (95% confidence interval [CI]: 0.74–0.99) and 13.6% (95% CI: 0.79–0.98) lower odds of asthma and rhinitis, respectively. Acculturation was not associated with either outcome.

Conclusions

Earlier work documented that Hispanic children with significant contribution from African ancestry are at increased asthma risk; however, in Hispanic children who have little contribution from African ancestry, Amerindian ancestry was independently associated with lower odds for development of early-childhood asthma and rhinitis.

Biomarkers of Insecticide Exposure and Asthma in Children: A National Health and Nutrition Examination Survey (NHANES) 1999-2008 Analysis

Pesticide exposure is a potential risk factor for increased asthma prevalence among children. The authors used National Health and Nutrition Examination Survey (1999-2008) biomarker data to evaluate dialkylphosphate (DAP) urinary concentrations, serum dichlorodiphenyldichloroethylene (DDE), and asthma among school-aged children (Mexican American, Non-Hispanic Black, Non-Hispanic White). Poisson logistic regression included age, sex, nativity, poverty index ratio, tobacco smoke exposure, and body mass index covariates. No association was found between DAP (N=2,777) and asthma outcomes; adverse effect of DDE (N=940) was suggested for Current Wheeze. Subgroup analyses identified positive associations with some asthma outcomes among Non-Hispanic Blacks, whereas inverse associations were identified among Mexican Americans. Results support previous associations observed among children's DDE exposure and wheeze. Characterization of risk factors for pesticide exposure and disease recognition among Mexican Americans is needed.

Associations of allostatic load with sleep apnea, insomnia, short sleep duration, and other sleep disturbances: findings from the National Health and Nutrition Examination Survey 2005 to 2008

PURPOSE

To examine whether allostatic load (AL), a measure of cumulative physiologic dysregulation across biological systems, was associated with sleep apnea, insomnia, and other sleep disturbances.

METHODS

Data from the National Health and Nutrition Examination Survey 2005-2008 were used. AL was measured using nine biomarkers representing cardiovascular, inflammatory, and metabolic system functioning. A total of 3330 US adults aged 18 years and older were included in this study.

RESULTS

The prevalence of high AL (AL score  ≥3) was the highest among African Americans (26.3%), followed by Hispanic Americans (20.3%), whites (17.7%), and other racial/ethnic group (13.8%). After adjustment for sociodemographic and lifestyle factors, high AL was significantly associated with sleep apnea (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.40-2.63), snoring (OR, 2.20; 95% CI, 1.79-2.69), snorting/stop breathing (OR, 2.16; 95% CI, 1.46-3.21), prolonged sleep latency (OR, 1.42; 95% CI, 1.08-1.88), short sleep duration (<6 hours) (OR, 1.35; 95% CI, 1.00-1.82), and diagnosed sleep disorder (OR, 2.26; 95% CI, 1.66-3.08). There was no clear evidence that observed associations varied by sociodemographic characteristics.

CONCLUSIONS

This study suggests significant associations of high AL with sleep apnea, sleep apnea symptoms, insomnia component, short sleep duration, and diagnosed sleep disorder among US adults.

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.

Psychometric Evaluation of the Brief Acculturation Scale for Hispanics

This study examined the psychometric properties of the Brief Acculturation Scale for Hispanics (BASH), a four-item, language-based measure of acculturation. Participants in the study were 435 Hispanic Americans from a large metropolitan area with English or Spanish language preference. Internal consistency reliability was strong in both language-preference groups. Multiple-group confirmatory factor analysis was used to evaluate the structural validity of the measure. A unidimensional factor structure was found for both English and Spanish language-preference groups and items loaded equivalently across groups, demonstrating measurement invariance. The BASH had good convergent validity and incremental validity. Overall, this study provides further evidence that the BASH offers a brief, reliable, and valid measure of acculturation to be used among Hispanic Americans.

Nativity and serum concentrations of antioxidants in Mexican American children: a cross-sectional study

There is limited research on the effect of immigration on biological markers of nutrition among children of Mexican origin in the United States. The purpose of this cross-sectional study was to examine data from the Third National Health and Nutrition Examination Survey (NHANES III) (1988–1994), on a national and representative sample of 1559 Mexican American children, 4–16 years of age, and assess the associations of country of birth with serum concentrations of carotenoids, vitamin A, and vitamin E. In multiple regression analyses, Mexico-born Mexican American children had significantly higher serum concentrations of α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, vitamin A, and vitamin E than their counterparts who were born in the United States after adjustment for age, sex, poverty income ratio, level of education of family reference person, body mass index, total serum cholesterol, serum cotinine, total energy intake, and vitamin/mineral consumption. Our findings confirm evidence for a negative effect of immigration/acculturation on dietary quality in this population. These findings also suggest that immigrant Mexican families should be encouraged to maintain their consumption of fruits and vegetables. Prospective studies are needed to further assess the effects of immigration/acculturation on diet and other health outcomes in children of Mexican origin and immigrants.

Association between birthplace and current asthma: the role of environment and acculturation

OBJECTIVES

We evaluated associations between current asthma and birthplace among major racial/ethnic groups in the United States.

METHODS

We used multivariate logistic regression methods to analyze data on 102,524 children and adolescents and 255,156 adults in the National Health Interview Survey (2001-2009).

RESULTS

We found significantly higher prevalence (P < .05) of current asthma among children and adolescents (9.3% vs 5.1%) and adults (7.6% vs 4.7%) born in the 50 states and Washington, DC (US-born), than among those born elsewhere. These differences were among all age groups of non-Hispanic Whites, non-Hispanic Blacks, and Hispanics (excluding Puerto Ricans) and among Chinese adults. Non-US-born adults with 10 or more years of residency in the United States had higher odds of current asthma (odds ratio = 1.55; 95% confidence interval = 1.25, 1.93) than did those who arrived more recently. Findings suggested a similar trend among non-US-born children.

CONCLUSIONS

Current asthma status was positively associated with being born in the United States and with duration of residency in the United States. Among other contributing factors, changes in environment and acculturation may explain some of the differences in asthma prevalence.

Health, chronic conditions, and behavioral risk disparities among U.S. immigrant children and adolescents

OBJECTIVE

We examined differentials in the prevalence of 23 parent-reported health, chronic condition, and behavioral indicators among 91,532 children of immigrant and U.S.-born parents.

METHODS

We used the 2007 National Survey of Children's Health to estimate health differentials among 10 ethnic-nativity groups. Logistic regression yielded adjusted differentials.

RESULTS

Immigrant children in each racial/ethnic group had a lower prevalence of depression and behavioral problems than native-born children. The prevalence of autism varied from 0.3% among immigrant Asian children to 1.3%-1.4% among native-born non-Hispanic white and Hispanic children. Immigrant children had a lower prevalence of asthma, attention deficit disorder/attention deficit hyperactivity disorder; developmental delay; learning disability; speech, hearing, and sleep problems; school absence; and ≥ 1 chronic condition than native-born children, with health risks increasing markedly in relation to mother's duration of residence in the U.S. Immigrant children had a substantially lower exposure to environmental tobacco smoke, with the odds of exposure being 60%-95% lower among immigrant non-Hispanic black, Asian, and Hispanic children compared with native non-Hispanic white children. Obesity prevalence ranged from 7.7% for native-born Asian children to 24.9%-25.1% for immigrant Hispanic and native-born non-Hispanic black children. Immigrant children had higher physical inactivity levels than native-born children; however, inactivity rates declined with each successive generation of immigrants. Immigrant Hispanic children were at increased risk of obesity and sedentary behaviors. Ethnic-nativity differentials in health and behavioral indicators remained marked after covariate adjustment.

CONCLUSIONS

Immigrant patterns in child health and health-risk behaviors vary substantially by ethnicity, generational status, and length of time since immigration. Public health programs must target at-risk children of both immigrant and U.S.-born parents.

Sleep characteristics and health-related quality of life among a national sample of American young adults: assessment of possible health disparities

PURPOSE

The aim of the study is to examine the associations of sleep characteristics with health-related quality of life (HRQOL) and sleep health disparities among US young adults using national survey data.

METHODS

The study sample consisted of 2,391 young adults aged 20-39 years from the National Health and Nutrition Examination Survey 2005-2008. HRQOL was assessed using the Centers for Disease Control and Prevention's HRQOL-4 scale. Multivariable logistic regression models were applied to evaluate the sleep-HRQOL associations. Stratified analyses were conducted to examine whether the associations varied by sociodemographic characteristics.

RESULTS

Approximately 35.6 % of young adults slept <7 h, 41.9 % had insomnia, 4.4 % had sleep disorder, and 8.5 % had sleep apnea. More females had insomnia than males (48.6 vs. 35.9 %, P < 0.001). US-born young adults had more sleep disturbances than their foreign-born counterparts. Compared with those sleeping 7-8 h, the adjusted odds ratio of poor general health was 1.60 (95 % confidence interval, 1.08-2.35) for individuals sleeping 6-7 h and 1.88 (1.23-2.86) for those sleeping <6 h. Similar results were found for low mental HRQOL and overall HRQOL. Insomnia, long sleep latency, troubling falling asleep, daytime sleepiness, and frequent sleeping pill use were significantly associated with low mental HRQOL and overall HRQOL. The associations between sleep disturbances and low HRQOL varied little by sex, race/ethnicity, and country of birth.

CONCLUSIONS

Sleep disturbances are common among US young adults and are significantly associated with low HRQOL. Objective measures of sleep are warranted to confirm our findings.

Intra-ethnic disparities in respiratory health problems among Hispanic residents impacted by a flood

OBJECTIVES

The primary objective of this article is to assess the respiratory health impacts of a flood disaster on Hispanic people residing in the United States, with a focus on intra-ethnic disparities related to age, sex, socioeconomic status, mold exposure, family conflict, English-language proficiency, and a lack of US citizenship.

METHODS

Data were collected in 2010 after a flood disaster (2006) in El Paso County (Texas), which has a Hispanic majority population. A mail-out population-based survey was used retrospectively to assess respiratory health impacts for 363 people residing in 176 self-identified Hispanic households impacted by the flood; logistic regression was utilized to assess intra-ethnic health disparities in flood impacts.

RESULTS

About 41% of individuals experienced one or more post-flood respiratory health problem. Lower income (OR = 0.532,p = .002), mold exposure (OR = 2.267, p < .001), increased family conflict (OR = 1.452, p = .025), English-language proficiency (OR = 4.023, p < .001) and a lack of US citizenship (OR = 13.111, p = .013) were significantly associated with higher odds of respiratory health problems in the regression model.

CONCLUSION

Statistical findings provide evidence of intra-ethnic disparities in post-flood respiratory health status. Specifically within this Hispanic sample, individuals with lower household incomes, whose homes were covered by larger surface areas of mold, and whose families were characterized by increased tension experienced higher odds of post-flood respiratory health problems. Interestingly, greater English-language proficiency and lacking US citizenship were also risk factors. Given that this is one of the first studies of intra-Hispanic disparities in health following a US-based disaster, the findings underscore the importance of considering diversity within the US Hispanic population when studying environmental and post-disaster respiratory health.

Early respiratory morbidity in a multicultural birth cohort: the Generation R Study

Ethnic disparities in the prevalence of asthma symptoms in children have been described. We evaluated to what extent the association between ethnic background and respiratory symptoms during the first 2 years of life could be explained by the mediating effect of risk factors for respiratory morbidity. The Generation R Study is a multiethnic, population-based birth cohort study. Pre and postnatal risk factors for respiratory morbidity were prospectively assessed by questionnaires. Information about ethnicity was available for 5,684 infants. The associations between ethnic background and lower respiratory symptoms at 12 and 24 months were evaluated with log-binomial regression models. Relative risks and 95 % confidence intervals (RR [95 % CI]) were computed for Cape Verdean, Moroccan, Antillean, Surinamese and Turkish ethnicity with Dutch ethnicity as the reference category. We found an increased risk of lower respiratory symptoms at 24 months in Antillean infants (1.32 [95 % CI 1.12-1.57]) that was mediated by early postnatal exposures (pets keeping, siblings, breastfeeding, daycare attendance, smoke exposure). Turkish infants also had an increased risk of lower respiratory symptoms at 12 and 24 months (1.14 [95 % CI 1.02-1.27] and 1.21 [95 % CI 1.07-1.38], respectively), partly explained by previous morbidity (eczema, infections and upper respiratory symptoms). There were no differences for Cape Verdean, Moroccan or Surinamese, as compared to Dutch infants. Hence, ethnic background was associated with respiratory symptoms during the first 2 years of life and this association was largely explained by mediating effects of known pre and postnatal risk factors for respiratory morbidity.

Socio-demographic disparities of childhood asthma

Childhood asthma is particularly prevalent among disadvantaged children and is associated with greater functional consequences. This study described factors associated with childhood asthma in a sample of Latino and non-Latino children. Data were from baseline measures of 791 parent and child dyads involved in a childhood obesity prevention study. Parents completed a self-administered survey assessing childhood factors, demographics, acculturation and child asthma diagnosis. Multivariate mixed effects logistic regression analyses tested for correlates of child asthma and ethnicity interactions. Children were 4-10 years old, half were female, 86.0 percent were US-born and 45.7 percent were overweight or obese. The prevalence of childhood asthma was 11.5 percent. In multivariate analyses, the odds of childhood asthma were greater among children of non-Latino descent (OR = 4.1, CI: 1.8, 9.2), who had health insurance (OR = 11.1, CI: 2.7, 46.4), were male (OR = 1.8; CI: 1.1, 3.1) and born pre-term (OR = 3.0, CI: 1.4, 6.3). This study supports socio-demographic disparities in childhood asthma and evidence of their independent effects.

Personal and parental nativity as risk factors for food sensitization

BACKGROUND

Immigrants to developed countries have low rates of aeroallergen sensitization and asthma, but less is known about both food allergy and the role of parental immigration status.

OBJECTIVE

We sought to evaluate the relationship between personal and parental nativity and the risk of food sensitization.

METHODS

Three thousand five hundred fifty subjects less than 21 years old from the Nation Health and Examination Survey 2005-2006 were included. Odds ratios (ORs) were generated by using logistic regression, which adjusted for race/ethnicity, sex, age, and household income and accounted for the complex survey design. Nativity was classified as US-born or foreign-born, and the age of immigration was estimated. Head-of-household nativity was used as a proxy for parental nativity. Food sensitization was defined as at least 1 specific IgE level of 0.35 kU/L or greater to milk, egg, or peanut. Aeroallergen-specific sensitizations and the presence of asthma, allergic rhinitis, or eczema were also assessed.

RESULTS

Compared with those born outside the United States (US), US-born children and adolescents had higher odds of sensitization to any food (OR, 2.05; 95% CI, 1.49-2.83; P < .001). Among the foreign-born group, those who arrived before 2 years of age had higher odds of food sensitization than those who arrived later (OR, 2.68; 95% CI, 1.19-6.08; P = .02). Within the US-born group, in contrast, children of immigrants were at the highest risk (OR, 1.53; 95% CI, 1.05-2.24; P = .02).

CONCLUSION

Although foreign-born children and adolescents are at lower risk of food sensitization compared with those born in the US, among those born in the US, the children of immigrants are at the highest risk.

Lessons for primary prevention of asthma: foreign-born children have less association of SES and pests with asthma diagnosis

There are no proven interventions for primary prevention of asthma. As asthma prevalence varies globally, comparing asthma in native and foreign-born children might provide insights. We pooled data from five cross sectional asthma surveys (N = 962). Place of birth was associated with asthma (OR = 3.4, P < 0.001). In children not born in the US, lower socio-economic status had no significant effect on asthma (OR = 0.71, P = 0.53), while for children born in the US, the effect was significant (OR = 2.1, P = 0.001). The odds ratio for exposure to household pests was significant (OR = 1.6, P < 0.008) for children born in the US but was non-significant for children born outside the US (OR = 0.29, P = 0.11). Our findings are consistent with foreign-born children experiencing protective factors or US born children experiencing detrimental environmental exposures.

Health selection among migrants from Mexico to the U.S.: childhood predictors of adult physical and mental health

OBJECTIVES

We tested whether positive selection on childhood predictors of adult mental and physical health contributed to health advantages of Mexican-born immigrants to the United States relative to U.S.-born Mexican Americans.

METHODS

We combined data from surveys conducted during 2000-2003 in Mexico and the U.S. with the same structured interview. We examined retrospective reports of childhood (i.e., < 16 years of age) predictors of adult health--education, height, childhood physical illness, childhood mental health, early substance use, and childhood adversities--as predictors of migration from Mexico to the U.S. at > or = 16 years of age. We estimated overall selection by comparing migrants to all non-migrants. We also examined selection at the family (members of families of migrants vs. members of families without a migrant) and individual (migrants vs. non-migrants within families of migrants) levels.

RESULTS

Distinguishing between family and individual selection revealed evidence of positive health selection that is obscured in the overall selection model. In particular, respondents in families with migrants were more likely to have > or = 12 years of education (odds ratio [OR] = 1.60) and be in the tallest height quartile (OR = 1.72) than respondents in families without migrants. At both the family and individual levels, migrants are disadvantaged on mental health profiles, including a higher prevalence of conduct problems, phobic fears, and early substance use.

CONCLUSIONS

Positive health selection may contribute to physical health advantages among Mexican immigrants in the U.S. relative to their U.S.-born descendants. Mental health advantages likely reflect a lower prevalence of psychiatric disorders in Mexico, rather than protective factors that distinguish migrants.

Helminthic therapy: using worms to treat immune-mediated disease

There is an epidemic of immune-mediated disease in highly-developed industrialized countries. Such diseases, like inflammatory bowel disease, multiple sclerosis and asthma increase in prevalence as populations adopt modern hygienic practices. These practices prevent exposure to parasitic worms (helminths). Epidemiologic studies suggest that people who carry helminths have less immune-mediated disease. Mice colonized with helminths are protected from disease in models of colitis, encephalitis, Type 1 diabetes and asthma. Clinical trials show that exposure to helminths reduce disease activity in patients with ulcerative colitis or Crohn's disease. This chapter reviews some of the work showing that colonization with helminths alters immune responses, against dysregulated inflammation. These helminth-host immune interactions have potentially important implications for the treatment of immune-mediated diseases.

Variability in childhood allergy and asthma across ethnicity, language, and residency duration in El Paso, Texas: a cross-sectional study

BACKGROUND

We evaluated the impact of migration to the USA-Mexico border city of El Paso, Texas (USA), parental language preference, and Hispanic ethnicity on childhood asthma to differentiate between its social and environmental determinants.

METHODS

Allergy and asthma prevalence was surveyed among 9797 fourth and fifth grade children enrolled in the El Paso Independent School District. Parents completed a respiratory health questionnaire, in either English or Spanish, and a sub-sample of children received spirometry testing at their school. Here we report asthma and allergy outcomes across ethnicity and El Paso residency duration.

RESULTS

Asthma and allergy prevalence increased with longer duration of El Paso residency independent of ethnicity and preferred language. Compared with immigrants who arrived in El Paso after entering first grade (18%), lifelong El Paso residents (68%) had more prevalent allergy (OR, 1.72; 95% CI, 1.32 - 2.24), prevalent asthma (OR, 1.75; 95% CI, 1.24 - 2.46), and current asthma (OR, 2.01; 95% CI, 1.37 - 2.95). Spirometric measurements (FEV1/FVC and FEF25-75) also declined with increasing duration of El Paso residency (0.16% and 0.35% annual reduction, respectively).

CONCLUSION

These findings suggest that a community-wide environmental exposure in El Paso, delayed pulmonary development, or increased health of immigrants may be associated with allergy and asthma development in children raised there.

Disparities in allergy testing and health outcomes among urban children with asthma

BACKGROUND

Previous research has found that treating allergies and reducing exposure to allergens can reduce asthma morbidity.

OBJECTIVE

We sought to examine whether urban asthmatic children were receiving care for allergies as part of a comprehensive asthma management plan.

METHODS

A cross-sectional study, consisting of a parent-reported questionnaire, was conducted in 26 randomly selected New York City public elementary schools during the 2002-2003 school year.

RESULTS

In a sample of 5,250 children aged 5 to 12 years, 13.0% were found to have current asthma. The prevalence of allergy diagnosis was 21.0%. Less than half (47.3%) of the subjects with current asthma reported a physician's diagnosis of allergies. The frequency of a reported allergy diagnosis varied with race/ethnicity, ranging from 14.4% in Mexican American children to 67.9% in white children. Only 54.9% of asthmatic children with an allergy diagnosis reported allergy testing. Children from lower-/middle-income households and children with public forms of health insurance were the least likely to report testing (adjusted odds ratios, 0.18 and 0.46). Higher frequencies of reported allergy testing were associated with education on allergen avoidance, use of allergy medications, lower exposure to household allergens, and lower prevalence of wheezing.

CONCLUSIONS

Many children do not receive comprehensive asthma treatment that includes management of allergies and education on avoidance of household allergens. Lower reported allergy testing might indicate lower access to medical care among middle-income families who are ineligible for public programs but who do not have the income to access higher-quality care. Interventions aimed at improving medical care and adherence to treatment guidelines are necessary to decrease asthma morbidity.

Community-level data suggest that asthma prevalence varies between U.S. and foreign-born black subpopulations

For Mexican and Chinese immigrants it has been reported that foreign born children have a lower prevalence of asthma than U.S.-born children. Inner-city black populations have a high prevalence of asthma. However, despite growing populations of black immigrants, we are aware of no previous studies that have looked at the effect of nativity on their asthma prevalence. We report data collected from a convenience sample in the Dorchester neighborhood of Boston for black respondents. The survey was conducted by medical students and community residents using a community-based participatory research approach. For adult respondents (n = 290) there was a strong negative association between being born outside the United States and reporting asthma (OR = 0.39; p = 0.033) that was retained in our multivariate model. For children (n = 157, reported by their parents) there was also a strong association with being born outside the United States (p < 0.05 using chi(2) tabular analysis); however, there were no foreign-born children with asthma so an OR could not be calculated and this association could not be carried forward into multivariate analyses. For children, but not adults, there were also strong associations between asthma and environmental factors. These findings point to the need for further research into nativity and asthma in black U.S. populations. Future studies should seek to obtain a representative sample, gather more demographic data than we did and seek a larger sample of children. It makes sense to ask about nativity in asthma prevalence studies in order to distinguish these two apparently very different subpopulations.

[Helminths and inflammatory bowel diseases]

The current etiologic model of inflammatory bowel diseases proposes a genetically predisposed host responding to a variety of environmental triggers by exhibiting an abnormal immune response to normal luminal flora. Crohn's disease is common in highly industrialized western countries where helminths are rare and uncommon in less developed areas of the world where most people carry worms. From this observation grew the hygiene hypothesis, which states that our failure to be exposed to previously common infectious agents alters the immune repertoire established in childhood. Helminths diminish immune responsiveness in naturally colonised humans and reduce inflammation in experimental colitis. Crohn's disease involves over reactive T-helper (Th1) pathways, and helminths blunt Th1 responses, inducing production of Th2 cytokines. Helminths also induce regulatory T cells to maintain host mucosal homeostasis. Thus, there is an immunological basis to expect that exposure to helminths such as Trichuris suis will prove beneficial in Crohn's disease. Exposure to helminths may be effective in treating inflammatory bowel diseases and was well tolerated, according to the results of few studies. Its long-term safety remains unknown.

Race, ethnicity and social class and the complex etiologies of asthma

Asthma is a common but complex respiratory disease caused by the interaction of genetic and environmental factors. Significant racial and ethnic disparities in prevalence, mortality and drug response have been described. These disparities may be explained by racial and ethnic-specific variation in genetic, environmental, social and psychological risk factors. In addition, race, ethnicity and social class are important proxies for unmeasured factors that influence health outcomes. Herein, we review salient differences in the etiologies of asthma by race, ethnicity and social class, and argue for their continued use as variables in asthma research.

Native and foreign born as predictors of pediatric asthma in an Asian immigrant population: a cross sectional survey

BACKGROUND

Asthma prevalence is lower in less developed countries and among some recent immigrant populations in the US, but the reasons for this are not clear. One possibility is that early childhood infections are protective against asthma.

METHODS

We surveyed Asian immigrant children (n = 204; age 4-18) to assess the relationship between asthma and native or foreign place of birth. We included questions about environmental exposures, demographic variables and family history of asthma to test whether they might explain effects of place of birth on asthma.

RESULTS

The native and foreign born groups were similar in most respects. Analysis of association with diagnosed asthma for all ages together resulted in two logistic regression models. Both retained born in the US (ORs were 3.2 and 4.3; p < 0.01) and family history of asthma (ORs were 6.4 and 7.2; p < 0.001). One model retained living near heavy motor traffic (OR = 2.6; p = 0.012). The other retained language (OR = 3.2; p = 0.003). However, for older children (11-18 years of age) being born in the US lost some of its predictive power.

CONCLUSION

Our findings are consistent with early childhood infections that are prevalent outside the US protecting against asthma.

Helminths as governors of immune-mediated inflammation

Immune-mediated diseases (e.g. inflammatory bowel disease, asthma, multiple sclerosis and autoimmune diabetes) are increasing in prevalence and emerge as populations adopt meticulously hygienic lifestyles. This change in lifestyles precludes exposure to helminths (parasitic worms). Loss of natural helminth exposure removes a previously universal Th2 and regulatory immune biasing imparted by these organisms. Helminths protect animals from developing immune-mediated diseases (colitis, reactive airway disease, encephalitis and diabetes). Clinical trials show that exposure to helminths can reduce disease activity in patients with ulcerative colitis or Crohn's disease. This paper summarises work by multiple groups demonstrating that colonization with helminths alters immune reactivity and protects against disease from dysregulated inflammation.