The relationship of blood lead with immunoglobulin E, eosinophils, and asthma among children: NHANES 2005-2006

Early life lead exposure may alter immune function and predispose a child to develop asthma. In an initial exploration of this hypothesis, we examined the association between blood lead, and serum immunoglobulin E (IgE), eosinophils, and asthma prevalence in a cross-sectional study of 1788 children from the National Health and Nutrition Examination Survey 2005-2006. Geometric mean blood lead, serum IgE, and percent eosinophils were 1.13 mu g/dL (95% confidence interval (CI): 1.04, 1.22), 46.3 kU/L (95% CI: 40.3, 53.1), and 2.82 percent (95% CI 2.67, 2.98), respectively. Prevalence of asthma, atopic asthma, and atopy were 11.8% (95% CI: 9.5, 14.2), 8.1% (6.2, 9.9), and 44.4% (40.1, 48.7), respectively. Regression models controlled for season, age, sex, race/ethnicity, education, passive smoke exposure, and body mass index. Based on these models, there was an 11.1% (95% CI: 5.6, 16.9) increase in IgE and a 4.9% (95% CI: 2.3, 7.6) increase in eosinophils per 1 mu g/dL increase in blood lead. In independent stratified analyses, lead was found to increase IgE and eosinophils among non-Hispanic whites, but not other children; and stronger associations were observed among children who lived with a smoker vs. not. Lead was not associated with asthma, atopic asthma, or general atopy. This study provides additional evidence of a cross-sectional association between lead with IgE and new evidence for eosinophils. This may be a mechanism for development of downstream allergic disease. The mechanisms that determine ultimate development of allergic disease are currently unknown, but are the focus of ongoing studies. (C) 2013 Elsevier GmbH. All rights reserved.