Eva Hernandez

Relationships of Race and Socioeconomic Status with Prevalence, Severity, and Symptoms of Asthma in Chicago School Children

BACKGROUND Asthma mortality rates in Chicago are among the highest in the United States, with substantially greater rates in poor and minority populations. How much of the differential can be attributed to differences in prevalence versus severity or access to care has not been determined. OBJECTIVE To examine rates of asthma prevalence, severity, and symptoms and to explore the relationships of these rates to race and socioeconomic status in a random sample of Chicago school children. METHODS Self-administered survey. RESULTS Overall, rates of asthma were higher than previously reported, with 16% of students in the stratified cluster random sample of 3,670 children in the 7th and 8th grades having had asthma. Prevalence rates were significantly higher in schools with >98% African Americans than in other schools, with the highest prevalence rates seen in African American schools in low income neighborhoods. Rates were associated with the percent of African American children in the school and with median income of the schools census tract. Relationships were most consistent with indices of more severe disease. CONCLUSIONS Asthma prevalence is higher than previously noted, with rates greatest in minority and low income populations. Differences are more striking for measures of severity than for symptoms of wheezing, but are far less than previously reported differences in mortality, suggesting that additional factors, such as differential access to continuous health care, may be affecting high death rates from asthma in Chicago.

Stressful life events and asthma in adolescents

Recent studies suggest that psychosocial factors may contribute to asthma. We examined associations of stressful life events with asthma prevalence and morbidity among Chicago adolescents. Self‐reported asthma, measures of asthma morbidity, and 15 life events were collected from 2026 seventh to ninth grade students from 34 Chicago Catholic schools as part of the International Study of Allergies and Asthma in Childhood in 1994–95. Life events were reported by 77% of adolescents and overall asthma prevalence was 15.5%. Stressful life events in adolescents were significantly related to both asthma and asthma morbidity. Odds of asthma was 1.44 (95% confidence interval [CI] = 1.07, 1.95) for those reporting two to three stressful events and 1.92 (95% CI = 1.41, 2.62) for subjects endorsing more than three stressful events. In adolescents with asthma, number of asthma symptoms (odds ratio [OR] for increase in one event = 1.16, 95% CI = 1.07, 1.27), asthma‐related school absenteeism (OR = 1.17, 95% CI = 1.04, 1.32), physician visits for asthma (OR = 1.16, 95% CI = 1.04, 1.29), and hospitalization for asthma (OR = 1.20, 95% CI = 1.001, 1.44) were significantly associated with the number of stressful events, independent of home exposure to cigarette smoke and dampness, use of inhaled substances, and sociodemographic factors. While these results are not sufficient to assign causality in the relationship between stress and asthma, they are supported by a number of other studies and by plausible biologic mechanisms. Assessing and addressing the effects of stressful life events may be helpful in managing asthma in inner city adolescents.

Prenatal exposure to acetaminophen and respiratory symptoms in the first year of life

BACKGROUND Prevalence of asthma in developed countries increased between the 1970s and the 1990s. One factor that might contribute to the trends in asthma is the increased use of acetaminophen vs aspirin in children and pregnant women. OBJECTIVE To examine relationships between in utero exposure to acetaminophen and incidence of respiratory symptoms in the first year of life. METHODS A total of 345 women were recruited in the first trimester of pregnancy and followed up with their children through the first year of life. Use of acetaminophen in pregnancy was determined by questionnaire and related to incidence of respiratory symptoms. RESULTS Use of acetaminophen in middle to late but not early pregnancy was significantly related to wheezing (odd ratio, 1.8; 95% confidence interval, 1.1-3.0) and to wheezing that disturbed sleep (odds ratio, 2.1; 95% confidence interval, 1.1-3.8) in the first year of life after control for potential confounders. CONCLUSION This study suggests that use of acetaminophen in middle to late but not early pregnancy may be related to respiratory symptoms in the first year of life. Additional follow-up will examine relationships of maternal and early childhood use of acetaminophen with incidence of asthma at ages 3 to 5 years, when asthma diagnosis is more firmly established.

Environmental Allergens and Asthma Morbidity in Low-Income Children

Asthma morbidity is high in inner-city children in the United States, which may be related in part to increased allergens in poorly maintained housing. This study examined asthma morbidity in relation to mold, cockroach, dust mite, and cat allergens in the homes of 61 low-income Chicago children with asthma. Children exposed to higher levels of Penicillium in the bedroom had more frequent asthma symptoms, whereas those exposed to higher levels of cockroach allergen in the bedroom had a higher number of asthma symptoms. Respiratory infections confounded the association of cockroach allergen with number of asthma symptoms.

Relationship between prenatal antibiotic use and asthma in at-risk children.

BACKGROUND Asthma prevalence has doubled in developed countries during the past 30 years. Pre- and perinatal events are essential in shaping the development of the immune system and systemic antibiotic use during this time could alter the maternal or placental microbiome, leading to an increase in the childs risk of developing asthma. OBJECTIVE To determine whether prenatal antibiotic use is associated with asthma and wheezing in children at risk for asthma. METHODS Using data from a randomized education intervention of families at risk for asthma from 1998 followed through 2009 in urban Chicago, asthma was defined as ever having a physician asthma diagnosis by year 3 and wheezing in the third year. Logistic regression models controlling for confounders investigated the effect of antibiotic use during pregnancy on these outcomes. RESULTS After adjustment, prenatal antibiotic use was a risk factor for asthma (odds ratio 3.1, 95% confidence interval 1.4-6.8) but was only weakly associated with wheezing (odds ratio 1.8, 95% confidence interval 0.9-3.3). Analyses of the effects of timing of prenatal antibiotic use on asthma and wheezing showed the relation remained consistent for antibiotic use later in pregnancy, but the outcomes were not associated with antibiotic use in the first trimester. CONCLUSION This study suggests prenatal antibiotic use might be associated with the development of asthma in children at risk for asthma. Although the relation with prenatal antibiotics does not hold for wheezing in this study, there might be a trend that could be delineated further within a larger cohort study.

Associations of Doctor-Diagnosed Asthma with Immigration Status, Age at Immigration, and Length of Residence in the United States in a Sample of Mexican American School Children in Chicago

OBJECTIVES Among Mexican Americans in the United States, children who were born in the US had higher rates of asthma than their Mexico-born peers. The purpose of this study was to examine the associations of doctor-diagnosed asthma with immigration-related variables and to investigate whether these associations could be explained by factors that may change with migration. METHODS We surveyed parents of 2,023 school children of Mexican descent and examined the associations of asthma with nativity, age at immigration, and length of residence in the US after adjusting for potential confounding variables. RESULTS In multivariate analyses, US-born children had a 2.42-fold (95% confidence interval [CI]: 1.52-3.83) increased odds of asthma compared with their Mexico-born peers. Mexico-born participants who moved to the US before 2 years of age were almost twice as likely to experience asthma compared with Mexico-born children who moved to the US >or=2 years of age. In addition, Mexico-born participants who lived in the US for 10 years or more were 2.37 times more likely to have asthma than Mexico-born students who lived in the US for less than 10 years. These associations were not explained by a wide variety of factors such as place of residence in infancy; exposure to animals/pets; history of infections, Tylenol use, and antibiotic use in infancy; breastfeeding; exposure to environmental tobacco smoke; daycare attendance and number of siblings; and language use. CONCLUSIONS Our findings point to the effects of nativity, age at immigration, and duration of residence in the US on the risk of asthma in Mexican American children, suggesting that potentially modifiable factors that change with migration may be linked with the disease. The findings of this study should stimulate further research to explain factors that may be responsible for the observed differentials in the risk of asthma among Mexican Americans.

The effect of low-cost modification of the home environment on the development of respiratory symptoms in the first year of life

BACKGROUND Previous studies have suggested that environmental exposures may be related to the development of respiratory symptoms in early life. Intervention studies, however, have not produced consistent findings. OBJECTIVE The Peer Education in Pregnancy Study examined the effect of home environment intervention with pregnant women at risk for having children with asthma on the development of respiratory symptoms in their infants. METHODS A total of 383 pregnant women whose unborn child had a first-degree relative with an allergic history were randomized to 1 of 2 intervention groups, both of whom received general health education, smoking cessation advice, and encouragement to breastfeed. In addition, the intensive education group received 3 home visits focused on home environment modification. Home assessment was performed at baseline and after 1 year of follow-up. Respiratory symptoms were identified during the first year of life. RESULTS Families in both intervention groups showed significant changes in several environmental factors, with significant differences between the 2 groups in insects other than cockroaches, use of mattress covers, and washing in hot water. Children in the intensive education group had slightly lower incidence rates of respiratory symptoms, but few differences were statistically significant. CONCLUSIONS The results of this study do not provide strong support for a primary intervention focused on general modification of the home environment during pregnancy for high-risk children. It does not address the effects of more aggressive approaches or of interventions targeting individual environmental factors.

Frequent ear infections in infancy and the risk of asthma in Mexican American children.

Objectives. This study examined the associations of history of ear infections in infancy with doctor-diagnosed asthma in a large sample of Mexican American children. Methods. In this population-based cross-sectional study, parents of 2023 children completed a questionnaire that collected data on doctor-diagnosed asthma, doctor-diagnosed ear infections, as well as antibiotics use in infancy, and other potential confounding variables. Results. Children with a history of ear infections in infancy were more likely to have asthma compared with those who had no history of ear infections in infancy; the adjusted odds ratios (ORs) were 2.52 (95% confidence interval [CI]: 1.35–4.69) and 1.27 (95% CI: 0.79–2.04) in children who had ≥3 and 1–2 (versus none) ear infections in infancy, respectively, p for trend = .0074. These associations were independent of antibiotics use, acetaminophen consumption, and history of various infections (other than ear infections) in the first year of life. In stratified analyses, the increased risk of asthma in children with recurrent ear infections in infancy persisted among children whose parents reported no lifetime history of rhinitis but not in children who had a history of rhinitis. Conclusions. This study demonstrated significant associations of asthma with history of ear infections in infancy, with a significant dose-response effect of repeated ear infections on the odds of asthma. These findings add to the growing body of literature linking early childhood infections with the risk of asthma and highlight the need for more research to identify the mechanisms through which ear infections may be associated with asthma.

Relationship between in utero C-reactive protein levels and asthma in at-risk children

BACKGROUND Asthma research has focused on postnatal exposures, but there is recent evidence to indicate atopic immune responses might be initiated in utero. Systemic inflammation during pregnancy might indicate an environment that could increase propensity in the child to develop allergic disease. OBJECTIVE To investigate the association of systemic inflammation, as measured by C-reactive protein (CRP) levels, with asthma and wheezing in offspring within an at-risk, mostly Mexican, cohort. METHODS Using data from a randomized education intervention of families at risk for asthma from 1998 followed through 2009 in urban Chicago, asthma was defined as ever having a physician diagnosis of asthma by 3 years of age and wheezing before the third year. Logistic regression models controlling for confounders investigated the effect of prenatal CRP levels on these outcomes. RESULTS There were 244 mother-child pairs included in the study analysis with median prenatal CRP levels of 4.9 mg/L (interquartile range 3.2-7.7). Continuous prenatal CRP levels were predictive of asthma by year 3 (relative risk 2.4, 95% confidence interval 1.3, 3.6) and wheezing in year 3 (relative risk 1.7, 95% confidence interval 1.1, 2.4) after adjustment. Associations remained significant in mothers who were of Mexican ethnicity and were nonsmokers, suggesting that effects might be stronger in children at lower risk of disease. CONCLUSION Prenatal CRP levels are associated with asthma by year 3 and wheezing in year 3 within a high-risk, urban, mostly Mexican, cohort. Maternal systemic inflammation might reflect a prenatal environment that could increase offspring susceptibility to develop wheezing and asthma young in life.