Original articleAsthma, lower airway diseaseIndoor particulate matter increases asthma morbidity in children with non-atopic and atopic asthma
Introduction
Asthma is influenced by a combination of host susceptibility and environmental factors, including viruses, pollutants, and allergens. Individuals with asthma often have allergic sensitization to allergens, and for these individuals, identification and avoidance of relevant allergens is an established component of asthma management. However, non-atopic asthma contributes significantly to the worldwide and US burden of disease, representing as much as 50% of the world's asthma, although atopic asthma likely predominates in children. Some evidence suggests that non-atopic asthma may confer a worse prognosis compared with atopic asthma1, 2, 3, 4, 5; however, because it is not considered an allergen-driven disease, environmental control recommendations are less well established.
Air pollutants are among the likely candidates of the possible environmental triggers for non-atopic asthma. Previous studies have suggested that air pollutants, such as sulfur dioxide, nitrogen dioxide, carbon monoxide, and benzene, have a stronger effect in non-atopic asthma than atopic asthma.6, 7 Particulate matter (PM) is a common air pollutant that has known detrimental health effects, especially for those with asthma. PM has both outdoor sources, including products of combustion and crustal materials, and indoor sources, including smoking, cooking, and cleaning activities.8, 9 Increases in ambient PM have been associated with greater morbidity in asthma and greater mortality in the general population.10, 11, 12, 13 However, the effect on non-atopic asthma has not been isolated.
Although Americans spend most of their time indoors (>80%), and indoor PM concentrations can exceed those measured outdoors, less is known about the health effects of indoor PM exposure. Previous studies of health effects of indoor PM have linked indoor PM exposure to increases in respiratory symptoms and decreases in pulmonary function but have not evaluated differential health effects of pollutants between atopic and non-atopic asthmatics.11, 14, 15, 16 To better understand the causative mechanism and to inform recommendations for improving the health of those with non-atopic asthma, we first need to provide evidence of the link between exposures and exacerbation of disease. The current study focuses on inner-city preschool-age children with asthma, a group known to have a high burden of disease and to be at risk for increased exposure to environmental pollutants. Using a cohort of well-characterized children with asthma,14, 17 we examined the response to indoor PM exposure in those with non-atopic and atopic asthma.
Section snippets
Study Design
The Johns Hopkins Medical Institutional Review Board approved the study, and all participants provided written informed consent before beginning the study. Children participating in this longitudinal study17 were evaluated at baseline and 3 and 6 months. At each interval, environmental monitoring occurred for 3 consecutive days, and health outcomes were assessed through caregiver report.
Participants
Children were recruited from health systems that provide care to most East Baltimore residents. Inclusion
Participant Characteristics
The 150 preschool children enrolled in this longitudinal cohort study were predominantly African American from lower-income households (Table 1). Of the 133 who completed allergy skin testing, 31% were classified as non-atopic and 69% as atopic. Non-atopic children were slightly younger, with a mean age of 3.9 years, compared with atopic children, who had a mean age of 4.6 years (P = .01). No significant differences were seen between the groups with respect to race, sex, or socioeconomic
Discussion
We found that in-home particle concentrations were associated with asthma morbidity, including symptoms and rescue medication use, among not only atopic but also non-atopic children. Although fewer non-atopic (n = 41) than atopic children (n = 92) were in this inner-city, predominantly African American cohort, we found substantial, statistically significant relationships between in-home PM concentrations and asthma outcomes in this group. The magnitude of the response to PM was similar in
Conclusions
In-home PM concentrations were associated with increased asthma symptoms and the need for rescue medication among both non-atopic and atopic preschool children living in inner-city Baltimore. This finding may be especially important for non-atopic asthmatics, because there are fewer alternative triggers compared with those with atopy. Future studies investigating the impact of interventions to reduce indoor PM and other indoor pollutants may be critical to better understanding the causative
References (49)
- et al.
Characterization of the severe asthma phenotype by the National Heart, Lung, and Blood Institute's Severe Asthma Research Program
J Allergy Clin Immunol
(2007) - et al.
Health effects of indoor nitrogen dioxide and passive smoking on urban asthmatic children
J Allergy Clin Immunol
(2007) - et al.
Common household activities are associated with elevated particulate matter concentrations in bedrooms of inner-city Baltimore pre-school children
Environ Res
(2008) - et al.
Effect of particulate air pollution on lung function in adult and pediatric subjects in a Seattle panel study
Chest
(2006) - et al.
Inner City Asthma Study: relationships among sensitivity, allergen exposure, and asthma morbidity
J Allergy Clin Immunol
(2005) - et al.
Household mouse allergen exposure and asthma morbidity in inner-city preschool children
Ann Allergy Asthma Immunol
(2006) - et al.
Mouse allergenII. The relationship of mouse allergen exposure to mouse sensitization and asthma morbidity in inner-city children with asthma
J Allergy Clin Immunol
(2000) - et al.
The immunopathology of extrinsic (atopic) and intrinsic (non-atopic) asthma: more similarities than differences
Immunol Today
(1999) - et al.
Challenge with environmental tobacco smoke exacerbates allergic airway disease in human beings
J Allergy Clin Immunol
(2006) - et al.
Home environmental intervention in inner-city asthma: a randomized controlled clinical trial
Ann Allergy Asthma Immunol
(2005)
Has the role of atopy in the development of asthma been over-emphasized?
Pediatr Pulmonol
How much asthma is really attributable to atopy?
Thorax
Non-IgE-mediated asthma in children
Acta Paediatr Scand
Non-atopic persistent asthma in children
Thorax
Inner city air pollution and respiratory health and atopy in children
Eur Respir J
Particle concentrations in inner-city homes of children with asthma: the effect of smoking, cooking, and outdoor pollution
Environ Health Perspect
Fine particulate air pollution and mortality in 20 U.S. cities, 1987–1994
N Engl J Med
Association of FEV1 in asthmatic children with personal and microenvironmental exposure to airborne particulate matter
Environ Health Perspect
An analysis of the association between respiratory symptoms in subjects with asthma and daily air pollution in Spokane, Washington
Inhal Toxicol
Prospective study of air pollution and bronchitic symptoms in children with asthma
Am J Respir Crit Care Med
In-home particle concentrations and childhood asthma morbidity
Environ Health Perspect
Pulmonary effects of indoor- and outdoor-generated particles in children with asthma
Environ Health Perspect
Home indoor pollutant exposures among inner-city children with and without asthma
Environ Health Perspect
Epidemiological evidence of effects of coarse airborne particles on health
Eur Respir J
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Disclosures: The authors have nothing to disclose.
Funding Sources: Supported by the NIEHS (K23 ES 016819; PO1 ES 09606; P50 ES 015903), NIAID (R01 AI070630) and U.S. EPA (PO1 R-826724), and the Johns Hopkins NIEHS Center in Urban Environmental Health (P30 ES 03819).