Asthma in US Mexican-Origin Children in Early Childhood: Differences in Risk and Protective Factors by Parental Nativity

The Intersection of Immigrant and Environmental Health: A Scoping Review of Observational Population Exposure and Epidemiologic Studies

BACKGROUND

Transnational immigration has increased since the 1950s. In countries such as the United States, immigrants now account for > 15 % of the population. Although differences in health between immigrants and nonimmigrants are well documented, it is unclear how environmental exposures contribute to these disparities.

OBJECTIVES

We summarized current knowledge comparing immigrants' and nonimmigrants' exposure to and health effects of environmental exposures.

METHODS

We conducted a title and abstract review on articles identified through PubMed and selected those that assessed environmental exposures or health effects separately for immigrants and nonimmigrants. After a full text review, we extracted the main findings from eligible studies and categorized each article as exposure-focused, health-focused, or both. We also noted each study's exposure of interest, study location, exposure and statistical methods, immigrant and comparison groups, and the intersecting socioeconomic characteristics controlled for.

RESULTS

We conducted a title and abstract review on 3,705 articles, a full text review on 84, and extracted findings from 50 studies. There were 43 studies that investigated exposure (e.g., metals, organic compounds, fine particulate matter, hazardous air pollutants) disparities, but only 12 studies that assessed health disparities (e.g., mortality, select morbidities). Multiple studies reported higher exposures in immigrants compared with nonimmigrants. Among immigrants, studies sometimes observed exposure disparities by country of origin and time since immigration. Of the 50 studies, 43 were conducted in North America.

DISCUSSION

The environmental health of immigrants remains an understudied area, especially outside of North America. Although most identified studies explored potential exposure disparities, few investigated subsequent differences in health effects. Future research should investigate environmental health disparities of immigrants, especially outside North America. Additional research gaps include the role of immigrants' country of origin and time since immigration, as well as the combined effects of immigrant status with intersecting socioeconomic characteristics, such as race/ethnicity, income, and education attainment. https://doi.org/10.1289/EHP9855.

Parent Nativity and Child Asthma Control in Families of Mexican Heritage: The Effects of Parent Depression and Social Support

OBJECTIVE

Research has repeatedly demonstrated that parent foreign nativity has a protective effect on child asthma outcomes among Mexican Americans, but the mechanisms underlying this relationship are not well understood. The current study explored parent depression as a mediator and social support as a moderator of the parent nativity-child asthma control pathway.

METHODS

Data come from the baseline sample of a trial (NCT02481986) testing community interventions for 223 children aged 5 to 16 with uncontrolled asthma. We focused on parent/child dyads of Mexican heritage (N = 165; mean age = 9.08, standard deviation = 2.94; 57.3% with Mexico-born parent). Asthma control was defined using the child and adult versions of the Asthma Control Test (ACT). Psychosocial factors included parent depression symptoms and social (instrumental, informational, and emotional) support.

RESULTS

Mexican-born parents had fewer depressive symptoms (β^ = -2.03, SE^ = 0.24) and children with better asthma control (β^ = 1.78, SE^ = 0.24) than US-born parents, P < .0001. Analyses suggested partial mediation of the nativity-ACT path via parent depression (P < .001). An interaction between Instrumental Support and Nativity was marginally significant (β^ = -0.10, SE^ = 0.05, P = .07), with protective effects only observed at higher support levels. Last, among Mexico-born parents, the protective nativity effects on ACT declined with increasing residential years in the United States through 12 years.

CONCLUSIONS

This study is novel in identifying parent depression as one mechanism underlying the effects of parent nativity on child asthma control, but results suggest that the health advantages may depend on availability of support. Providing resources for parent depression and instrumental support (transportation, childcare) can optimize asthma interventions in this population.

Infant milk-feeding practices and food allergies, allergic rhinitis, atopic dermatitis, and asthma throughout the life span: a systematic review

BACKGROUND

During the Pregnancy and Birth to 24 Months Project, the USDA and Department of Health and Human Services initiated a review of evidence on diet and health in these populations.

OBJECTIVES

The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding prior to infant formula introduction, 4) feeding a lower versus higher intensity of human milk to mixed-fed infants, and 5) feeding a higher intensity of human milk by bottle versus breast with food allergies, allergic rhinitis, atopic dermatitis, and asthma.

METHODS

The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published between January 1980 and March 2016, dual-screened the results according to predetermined criteria, extracted data from and assessed the risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence.

RESULTS

The systematic reviews numbered 1-5 above included 44, 35, 1, 0, and 0 articles, respectively. Moderate, mostly observational, evidence suggests that 1) never versus ever being fed human milk is associated with higher risk of childhood asthma, and 2) among children and adolescents who were fed human milk as infants, shorter versus longer durations of any human milk feeding are associated with higher risk of asthma. Limited evidence does not suggest associations between 1) never versus ever being fed human milk and atopic dermatitis in childhood or 2) the duration of any human milk feeding and allergic rhinitis and atopic dermatitis in childhood.

CONCLUSIONS

Moderate evidence suggests that feeding human milk for short durations or not at all is associated with higher childhood asthma risk. Evidence on food allergies, allergic rhinitis, and atopic dermatitis is limited.

Inflammation among Children: Evidence of an Immigrant Advantage?

Past research on the immigrant health paradox suggests that children with immigrant parents may have a health advantage over those with U.S.-born parents, especially if the parent is a recent immigrant. Other research emphasizes the social and economic challenges children with immigrant parents face, in part due to disadvantaged social class and racial/ethnic positions. Underlying physiological changes due to chronic stress exposures among children in immigrant families is one potential health disadvantage that may not yet be apparent in traditional health measures. To explore these biological disparities during childhood, I use national biomarker and survey data from NHANES (N=11,866) to evaluate parent nativity and educational status associations with low-grade inflammation, indicated by C-reactive Protein (CRP), in children ages 2-15 years. I find that children with an immigrant parent, and particularly a low-education immigrant parent, have higher CRP, net of birth, BMI and other factors, than children with a U.S. born parent with either a low or higher education. Comparing children with low-educated parents, those with a foreign-born parent have higher predicted CRP. The findings from this study provide new evidence that children living in immigrant families in the U.S. may be facing higher levels of chronic stress exposure, as indicated by the increased risk of low-grade inflammation, than those with U.S.-born parents. The physiological changes related to increased risk of inflammation could set children in immigrant families on pathways towards mental and physical health problems throughout childhood and later in the life course.

The impact of maternal smoking during pregnancy on childhood asthma: adjusted for exposure misclassification; results from the National Health and Nutrition Examination Survey, 2011-2012

PURPOSE

We sought to examine the association between childhood asthma and self-reported maternal smoking during pregnancy (MSDP) after adjusting for a range of exposure misclassification scenarios using a Bayesian approach that incorporated exposure misclassification probability estimates from the literature.

METHODS

Self-reported MSDP and asthma data were extracted from National Health and Nutrition Examination Survey 2011-2012. The association between self-reported MSDP and asthma was adjusted for exposure misclassification using a Bayesian bias model approach.

RESULTS

We included 3074 subjects who were 1-15 years of age, including 492 asthma cases. The mean (SD) of age of the participants was 8.5 (4.1) and 7.1 (4.2) years and the number (percentage) of female was 205 (42%) and 1314 (51%) among asthmatic and nonasthmatic groups, respectively. The odds ratio (OR) for the association between self-reported MSDP and asthma in logistic regression adjusted for confounders was 1.28 (95% confidence interval: 0.92, 1.77). In a Bayesian analysis that adjusted for exposure misclassification using external data, we found different ORs between MSDP and asthma by applying different priors (posterior ORs 0.90 [95% credible interval {CRI}: 0.47, 1.60] to 3.05 [95% CRI: 1.73, 5.53] in differential and 1.22 [CRI 95%: 0.62, 2.25] to 1.60 CRI: 1.18, 2.19) in nondifferential misclassification settings.

CONCLUSIONS

Given the assumptions and the accuracy of the bias model, the estimated effect of MSDP on asthma after adjusting for misclassification was strengthened in many scenarios.

Nativity as a Determinant of Health Disparities Among Children

Nativity is not often considered in the study of health disparities. We conducted a cross-sectional, parent-reported survey of demographics, socioeconomic characteristics, healthcare access, and health conditions in New York City schoolchildren (n = 9029). US-born children with US-born parents (US/US) had higher socioeconomic status, better access to healthcare, and reported higher rates of disease diagnoses compared to US-born children with immigrant parents and to immigrant children. Dental cavities were the only condition in which US/US children reported lower prevalence. US/US children had the best healthcare access, most favorable parent-reported health status and highest rate of satisfaction with healthcare. The magnitude of racial/ethnic disparities varied based on nativity of the children being compared. Factors such as the healthy immigrant effect and differential diagnosis rates may explain the results. In conclusion, nativity influences disease burdens and should be considered in health disparities studies.

The effect of early child care attendance on childhood asthma and wheezing: A meta-analysis

OBJECTIVE

Research evidence offers mixed results regarding the relationship between early child care attendance and childhood asthma and wheezing. A meta-analysis was conducted to synthesize the current research evidence of the association between early child care attendance and the risk of childhood asthma and wheezing.

METHOD

Peer reviewed studies published from 1964-January 2017 were identified in MEDLINE, CINAL, and EMBASE using MeSH headings relevant to child care and asthma. Two investigators independently reviewed the selected articles from this search. All relevant articles that met our inclusion criteria were selected for further analysis. Data were extracted from studies that had sufficient data to analyze the odds of asthma or wheezing among children who attended child care.

RESULTS

The meta-analysis of 32 studies found that (1) early child care attendance is protective against asthma in children 3-5 years of age but not for children with asthma 6 years of age or older. (2) Early child care attendance increases the risk of wheezing among children 2 years of age or younger, but not the risk of wheezing for children over 2 years of age.

CONCLUSIONS

This meta-analysis shows that early child care attendance is not significantly associated with the risk of asthma or wheeze in children 6 years of age or older.

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.