Academic journal article Environmental Health Perspectives

Air Pollution and Childhood Respiratory Allergies in the United States

Academic journal article Environmental Health Perspectives

Air Pollution and Childhood Respiratory Allergies in the United States

Article excerpt

Background; Childhood respiratory allergies, which contribute to missed school days and other activity limitations, have increased in recent years, possibly due to environmental factors.

OBJECTIVE: In this study we examined whether air pollutants are associated with childhood respiratory allergies in the United States.

METHODS: For the approximately 70,000 children from the 1999-2005 National Health Interview Survey eligible for this study, we assigned between 40,000 and 60,000 ambient pollution monitoring data from the U.S. Environmental Protection Agency, depending on the pollutant. We used monitors within 20 miles of the child's residential block group. We used logistic regression models, fit with methods for complex surveys, to examine the associations between the reporting of respiratory allergy or hay fever and annual average exposure to particulate matter [less then or equal to] 2.5 um in diameter (PM.sub.2.5), PM [less then or equal to] 10 [mu]m in diameter, sulfur dioxide, and nitrogen dioxide and summer exposure to ozone, controlling for demographic and geographic factors.

RESULTS: Increased respiratory allergy/hay fever was associated with increased summer [O.sub.3] levels [adjusted odds ratio (AOR) per 10 ppb = 1.20; 95% confidence interval (CI), 1.15-1.26] and increased [PM.sub.2.5] (AOR per 10 [mu]g/[m.sup.3] = 1.23; 95% CI, 1.10-1.38). These associations persisted after stratification by urban-rural status, inclusion of multiple pollutants, and definition of exposures by differing exposure radii. No associations between the other pollutants and the reporting respiratory allergy/hay fever were apparent.

CONCLUSIONS: These results provide evidence of adverse health for children living in areas with chronic exposure to higher levels of [O.sub.3] and [PM.sub.2.5] compared with children with lower exposures.

KEY WORDS: allergy, children, hay fever, ozone, particulate matter. Environ Health Perspect 117:14-147 (2009). doi:10.1289/ehp. 11497 available via [Online 30 September 2008]


Children in the United States are generally healthy; > 80% are in excellent or very good health according to the 2006 National Health Interview Survey (NHIS) (Bloom and Cohen 2007). However, a significant proportion of children are affected by respiratory conditions, including allergies, which are associated with missed school days and activity limitations (Blaiss 2004). Parent responses to questions in the 2007 NHIS indicate that about 9% of children < 18 years of age had had hay fever in the preceding 12 months, and slightly more had had respiratory allergies (Bloom and Cohen 2007). These estimates are higher than comparable statistics from the 1982 NHIS, where 5.5% of children were reported the previous 12 months [National Center for Health Statistics (NCHS) 1985]. Respiratory allergies manifest as a variety of symptoms of varying duration and severity. In a recent review, Blaiss (2004) concluded that childhood allergic rhinitis, or allergies, contributes to increased loss of school days, impaired school performance, and increased mental health disorders from the various allergic symptoms and resulting increased sleep disruptions. Recent data from the NHIS support this conclusion; in a simple cross-tabulation, children with respiratory allergies or hay fever were more likely to miss school than those without these conditions (Parker et al. 2007). A brief review by Simons (1996) describes the impacts of allergies, including effects of medications used to treat allergies, on learning impairment in children.

A possible factor affecting respiratory allergic symptoms is exposure to ambient air pollution, particularly traffic pollutants. Reviews of the effects of air pollution on allergies have concluded that pollutants likely exacerbate effects of allergens among those with existing susceptibility, rather than initiating allergies among people without existing allergies (e. …

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