Exposure to dust mite allergen and endotoxin in early life and asthma and atopy in childhood
- Publication Type:
- Journal Article
- Journal of Allergy and Clinical Immunology, 2007, 120 (1), pp. 144 - 149
- Issue Date:
Background: There has been no longitudinal study of the relation between concurrent exposure to dust mite allergen and endotoxin in early life and asthma and atopy at school age. Objectives: To examine the relation between exposure to dust mite allergen and endotoxin at age 2 to 3 months and asthma, wheeze, and atopy in high-risk children. Methods: Birth cohort study of 440 children with parental history of atopy in the Boston metropolitan area. Results: In multivariate analyses, early exposure to high levels of dust mite allergen (≥10 μg/g) was associated with increased risks of asthma at age 7 years (odds ratio [OR], 3.0; 95% CI, 1.1-7.9) and late-onset wheeze (OR, 5.0; 95% CI, 1.5-16.4). Exposure to endotoxin levels above the lowest quartile at age 2 to 3 months was associated with reduced odds of atopy at school age (OR, 0.5; 95% CI, 0.2-0.9). In contrast with its inverse association with atopy, endotoxin exposure in early life was associated with an increased risk of any wheeze between ages 1 and 7 years that did not change significantly with time (hazard ratio for each quartile increment in endotoxin levels, 1.23; 95% CI, 1.07-1.43). Conclusion: Among children at risk of atopy, early exposure to high levels of dust mite allergen is associated with increased risks of asthma and late-onset wheeze. In these children, endotoxin exposure is associated with a reduced risk of atopy but an increased risk of wheeze. Clinical implications: Early endotoxin exposure may be a protective factor against atopy but a risk factor for wheeze in high-risk children. © 2007 American Academy of Allergy, Asthma & Immunology.
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