Purpose of the Study. To establish the prevalence and socioeconomic pattern of allergic disease as well as the pattern of allergen sensitization to markers of socioeconomic status (SES).
Study Population. Participants were mothers (n = 458) of children in the Epidemiology of Home Allergen and Asthma Study (a longitudinal birth and family cohort study) with the following inclusion criteria: 1) delivered a child between September 1994 and June 1996 in Boston, Massachusetts, 2) ability to speak English or Spanish, and 3) mother or father had a doctor’s diagnosis of asthma, hayfever, or allergen sensitivity.
Methods. Markers of race, SES, and diagnosis of asthma, hay fever, or allergy were elicited by questionnaire. Using 1990 US Census data, a marker of poverty in the zip code of residence was evaluated in terms of the proportion of the population living below the poverty level. Serum was collected for total immunoglobulin (IgE) and specific IgE to mites, cat, cockroach, dog, ryegrass, ragweed, Alternaria, and Aspergillus using the UNICAP system.
Results. The population was 18 to 46 years old, mostly white (79%), educated to a college level or above (78%), and lived with a household income >$50 000 (70%). Only 5% smoked. Hayfever was reported in 43%, asthma in 31%, and eczema in 22%. When restricted to women with allergic disease and/or asthma, asthma was more common in areas of poverty while hayfever was more common in areas of affluence (P = .007). Eczema was not related to any markers of SES. Allergen sensitivity was found in 60%, with mite the commonest (36%) and Aspergillus the rarest (4%). Multiple sensitivities were typical, while only mite allergy occurred commonly as a sole sensitivity. Eleven percent had cockroach sensitivity with 94% also sensitive to 1 or more other allergens. Subjects living in areas of greatest poverty were at greatest risk for allergen sensitivities with cat, ragweed, and dog sensitivity common in high poverty areas. Sensitivity to cockroach allergen was much higher in relation to area poverty (P < .001). Sensitivities to mite and mold were equally common across all markers of SES. Ryegrass was the only allergen more common with markers of high SES. The mean total IgE levels was higher across areas of poverty (P < .001). Allergen sensitivity was increased in women of household incomes <$50 000. Asthma was significantly associated with cockroach, mite, and dander sensitivity, especially in those with higher specific IgE levels. Hayfever was associated with ragweed, ryegrass, and cat sensitivities. Eczema correlated with allergen sensitivity, but not to any specific allergen.
Conclusions. A socioeconomic gradient was demonstrated showing that the poorest had higher total and specific IgE levels, increased allergen sensitization, and asthma. Cockroach, cat, dog, and ragweed sensitivities were higher in the poorer areas, with additional risk the higher the specific IgE level. An increased risk for asthma was associated with cat, dog, and cockroach sensitivity. In contrast to asthma, hayfever was found to be more common in areas of affluence.
Reviewers’ Comments. In the United States, asthma prevalence is highest in the inner cities while in Europe asthma and allergic disease has been associated with greater affluence. This study provides a possible mechanism for the association of asthma and lower SES in the United States. Increased exposures to allergens may explain the increased incidence of asthma in the inner-city.
- Copyright © 2002 by the American Academy of Pediatrics