Risk for asthma in 1-year-old infants residing in New York City high-risk neighborhoods

Racial disparities in childhood asthma in the United States: evidence from the National Health Interview Survey, 1997 to 2003

OBJECTIVE

To examine differences in asthma prevalence and emergency department (ED) visits for asthma between non-Hispanic black and white children, and factors that might explain those differences, in a large, nationally representative sample covering the period 1997 to 2003.

METHODS

Bivariate and multivariate regression analyses (with logit and multinomial logit methods) were conducted with a sample consisting of all non-Hispanic black and white children (<18 years of age) from the 1997 to 2003 rounds of the National Health Interview Survey. Models included a progressively larger set of controls for factors that might explain racial differences in asthma prevalence and ED visits for asthma.

RESULTS

Being black was associated with a greater likelihood of currently having asthma and with a greater likelihood of having gone to the ED for asthma treatment in the past 1 year. Elevated asthma risks for black children were robust after controlling for a host of child and family characteristics that might explain them.

CONCLUSIONS

Black children are more likely to have asthma and to experience ED visits for asthma, compared with otherwise comparable white children, and these racial disparities cannot be explained by differences in measurable child or family characteristics. These results suggest that racial disparities in asthma continue to pose risks for black children, and they point to the need for additional research into potential explanations and remedies.

Endotoxin in inner-city homes: associations with wheeze and eczema in early childhood

BACKGROUND

An inverse association between domestic exposure to endotoxin and atopy in childhood has been observed. The relevance of this aspect of the hygiene hypothesis to US inner-city communities that have disproportionately high asthma prevalence has not been determined.

OBJECTIVES

To measure endotoxin in the dust from inner-city homes, evaluate associations between endotoxin and housing/lifestyle characteristics, and determine whether endotoxin exposure predicted wheeze, allergic rhinitis, and eczema over the first 3 years of life.

METHODS

As part of an ongoing prospective birth cohort study, children of Dominican and African-American mothers living in New York City underwent repeated questionnaire measures. Dust samples collected from bedroom floors at age 12 or 36 months were assayed for endotoxin.

RESULTS

Among the samples collected from 301 participants' homes, the geometric mean endotoxin concentration (95% CI) was 75.9 EU/mg (66-87), and load was 3892 EU/m2 (3351-4522). Lower endotoxin concentrations were associated with wet mop cleaning and certain neighborhoods. Endotoxin concentration correlated weakly with cockroach (Bla g 2: r = 0.22, P < .001) and mouse (mouse urinary protein: r = 0.28; P < .001) allergens in the dust. Children in homes with higher endotoxin concentration were less likely to have eczema at age 1 year (odds ratio, 0.70 [0.53-0.93]) and more likely to wheeze at age 2 years (odds ratio, 1.34 [1.01-1.78]). These associations were stronger among children with a maternal history of asthma.

CONCLUSION

Endotoxin levels in this inner-city community are similar to those in nonfarm homes elsewhere. In this community, domestic endotoxin exposure was inversely associated with eczema at age 1 year, but positively associated with wheeze at age 2 years.

CLINICAL IMPLICATIONS

Endotoxin exposure in the inner-city community may be related to wheeze in the early life; however, given the inverse association seen with eczema, the long-term development of allergic disease is still in question.

Prevalence of allergy symptoms and total IgE in a New York City cohort and their association with birth order

BACKGROUND

An inverse association between birth order and allergic disease has been widely observed, but has not been examined in the high asthma prevalence, inner-city populations of the United States. As part of an ongoing prospective birth cohort study, the prevalence of early phenotypes of asthma and/or allergy was compared with those reported in other studies, and the association with birth order was evaluated.

METHODS

Children of Dominican and African-American mothers living in Northern Manhattan underwent detailed periodic questionnaires. Total IgE from the mothers (n = 321) and the children at birth (n = 291) and at ages 24 (n = 244) and 36 (n = 155) months was measured. The association between birth order and allergy symptoms was evaluated at 12 (n = 350), 24 (n = 290) and 36 (n = 247) months.

RESULTS

Total serum IgE was detectable (>0.5 IU/ml) in 35% of the children's cord blood and averaged 15 and 21 IU/ml at ages 24 and 36 months, respectively. They were not significantly different at any age between children with and without older siblings. Additionally, at these ages, there were no consistent associations between birth order and either wheeze, itchy eyes or eczema.

CONCLUSIONS

Despite a substantially higher prevalence of asthma in the Northern Manhattan community compared with other areas, total IgE levels at ages 24 and 36 months, but not cord blood, are similar to those reported in other areas of the world. In this community, results at this age do not support a protective effect of higher birth order.