Preschool children's environmental exposures: A case-control epidemiological study of the presence of asthma-like symptoms

The heterogeneity of asthma and asthma-like symptoms results in difficulty defining, diagnosing, and therefore estimating environmental exposures and associations with wheezing or asthma-like symptoms. Determining the disease burden for young children is particularly challenging. In the study described in this article, counter-matched sampling design was used to select participants from the Woman, Infants, and Children (WIC) program for this nested case-control study (N = 691, with 412 controls). Data were collected through structured interviews. Exposure to wood or oil smoke, soot, or exhaust was significantly associated with early-life asthma, as was exposure to cockroaches. Multivariate analyses showed that increasing age, male gender, presence of allergies (although not the type of allergies), and the presence of eczema at birth predicted wheezing behaviors in the authors' study. The authors estimated the prevalence of wheezing behavior in a population of low-income preschool children was 31% with prevalence rates higher among African-American children as compared to other races/ethnicities. Fifty-one percent of those children whose caregivers reported wheezing, however, had not received a diagnosis of asthma. Further study is recommended to compare the differences in the wheezing experiences between those diagnosed with asthma and those who are undiagnosed, with the intent of designing primary prevention interventions tailored to parents and caregivers of young children.