Residential exposures are recognized risk factors for asthma, but the relative contribution of specific indoor allergens and their overall contribution to asthma among older children and adolescents in the United States are unknown.
To estimate the relative contributions, population-attributable risks, and costs of residential risk factors for doctor-diagnosed asthma.
Nationally representative, cross-sectional survey conducted from 1988 to 1994.
A total of 5384 children who were 6 to 16 years old and participated in the National Health and Nutrition Examination Survey III, a survey of the health and nutritional status of children and adults in the United States.
Doctor-diagnosed asthma, as reported by the parent.
Five hundred three of 5384 children and adolescents (11.4%) had doctor-diagnosed asthma. After adjusting for age, gender, race, urban status, region of country, educational attainment of the head of household, and poverty, predictors of doctor-diagnosed asthma included a history of allergy to a pet (odds ratio [OR: 2.4; 95% confidence interval [CI]: 1.7, 3.3), presence of a pet in the household (OR: 1.5; 95% CI: 1.1, 2.1), and immediate hypersensitivity to dust mite (OR: 1.5; 95% CI: 1.05, 2.0),Alternaria (OR: 1.9; 95% CI: 1.3, 2.8), and cockroach allergens (OR: 1.4; CI: 1.04, 1.9). Family history of atopy (OR: 1.7; 95% CI: 1.1, 2.7) and diagnosis of allergic rhinitis (OR: 2.1; CI: 1.1, 3.7) were also predictors for asthma. The population-attributable risk of having 1 or more residential exposures associated with doctor-diagnosed asthma was 44.4% (95% CI: 29–60), or an estimated 2 million excess cases. The attributable cost of asthma resulting from residential exposures was $405 million (95% CI: $264–$547 million) annually.
The elimination of identified residential exposures, if causally associated with asthma, would result in a 44% decline in doctor-diagnosed asthma among older children and adolescents in the United States.
Comments
Reply to Arithmetic
The proportion of children wiith asthma was correctly reported as 11.3%. Unfortunately, we did not specify that this was the weighted proportion. Weighting was necessary to account for the oversampling of minority children in the NHANES III survey.
Arithmetic
Since when did 503 out of 5384 become 11.3%?
<Q> 503 children with asthma from a population of 5384 looks like 9.3%, not 11.4%.
<A> As indicated by Dr. Sherman, the percentage of children with asthma in the sample of children surveyed was 9.3%. But because the NHANES oversampled minority populations, we reported the weighted estimate, that is the percentage or prevalence of children with asthma that is representative of the U.S. population (11.4%).
<Q> How did you accomplish skin testing when the only patient contact you describe is through a survey?
<A> NHANES III (National Health and Nutrition Examination Survey III), conducted by the National Center for Health Statistics, Centers for Disease Control, includes an interview, medical evalution, hearing tests, phlebotomy and, for children 6-16 years of age, skin tests for some common allergens. We used the term survey in the broader sense to indicate a full examination or "survey" of the study population.
<P> Your previous publication (Pediatr 2001;107:505) showed an increased OR for ETS in patients less than 6 yrs at the time of the survey. Both surveys used the response to "Were you ever told by a doctor that your child had asthma?" as the diagnostic criteria for asthma. Asthma before age 6 should have been a positive response for both studies. Why is it, then, that exposure to ETS was not a significant risk factor in the 6 to 16 yr group?
<A> ETS is a risk factor or irritant for asthma in younger children, but its role in asthma among older children and adolescents is less clear. The discrepancy identified by Dr. Sherman may indicate that allergen-induced asthma overwhelms any contribution of ETS to asthma in older children. It may also indicate recall bias by the parents who have children that no longer have asthma.
503 with asthma from a population of 5384 looks like 9.3%, not 11.4%
How did you accomplish skin testing when the only patient contact you describe is through a survey?
Your previous publication (Pediatr 2001;107:505) showed an increased OR for ETS in patients less than 6 yrs at the time of the survey. Both surveys used the response to "Were you ever told by a doctor that your child had asthma?" as the diagnostic criteria for asthma. Asthma before age 6 should have been a positive response for both studies. Why is it, then, that exposure to ETS was not a significant risk factor in the 6 to 16 yr group?