Endotoxin Exposure and Eczema in the First Year of Life

Abstract

Objective-Exposure to endotoxin in early life has been proposed as a factor that may protect against the development of allergic diseases such as eczema. The objective of this study was to examine the relation between endotoxin exposure in early life and eczema in the first year of life in children with parental history of asthma or allergies.Methods-This study used a prospective birth cohort study of 498 children who had a history of allergy or asthma in at least 1 parent and lived in metropolitan Boston. A subset of 401 living rooms had house dust samples adequate for analysis of endotoxin.Results-In multivariate analyses adjusting for gender, income, and season of birth, endotoxin levels in the living room at 2 to 3 months of age was inversely associated with physician-or nursediagnosed eczema in the first year of life (odds ratio [OR] for each quartile increment: 0.76; 95% confidence interval [CI]: 0.61-0.96). Exposure to a dog in the home at age 2 to 3 months was also inversely associated with eczema in the first year of life, but the CI widened when endotoxin was included in the multivariate model (OR: 0.54; 95% CI: 0.27-1.09). Other variables associated with eczema in the first year of life included paternal history of eczema (OR: 1.91; 95% CI: 1.03-3.55) and maternal specific immunoglobulin E positivity to ≥1 allergen (OR: 1.61; 95% CI: 1.01-2.56).Conclusions-Among children with parental history of asthma or allergies, exposure to high levels of endotoxin in early life may be protective against eczema in the first year of life. In these children, paternal history of eczema and maternal sensitization to at least 1 allergen are associated with an increased risk of eczema in the first year of life. ABBREVIATIONSIg, immunoglobulin; OR, odds ratio; CI, confidence interval; T h 2, T-helper cell type 2 Eczema is the most common atopic disease in infancy, and 60% of affected individuals manifest characteristic lesions during the first year of life. 1 The prevalence of eczema has increased by 2 to 3-fold during the past 3 decades in industrialized countries. Early childhood exposure to endotoxin has been hypothesized to be protective against the development of asthma, 4 allergy, 5-7 and eczema. 7 The Home Allergens and Asthma Study is a prospective birth cohort study of children with a parental history of asthma or allergies in the Boston metropolitan area. The primary purpose of this study is to assess the relationship between exposure to indoor allergens in early childhood and the subsequent development of asthma and allergic diseases. As part of this study, exposure to endotoxin in the household was measured at 2 to 3 months of age. In this report, we describe the relation between endotoxin exposure and eczema in the first year of life among children with parental history of asthma or allergies. METHODS Study ParticipantsThe 505 infants (including 6 sets of twins) and their 499 families with a history of allergy or asthma in at least 1 parent were recruited between September 1994 and August 1996. The ...

Endotoxin in inner-city homes: Associations with wheeze and eczema in early childhood

“…Similar to the Boston study, we found both a negative association between endotoxin exposure and eczema and positive association between endotoxin exposure and wheeze (25,32). The decreased risk for eczema and potential "protection" from early atopic disease is consistent with the "hygiene hypothesis."…”

“…Results from a relatively small study in metropolitan Denver found an inverse association with endotoxin concentration and atopy (3), while a positive association between endotoxin concentration and wheeze was found in a mixed urban and suburban birth cohort in Boston (32,33). This latter Boston study also found an inverse association between endotoxin and eczema (25).…”

“…Inverse associations between endotoxin in house dust and allergic sensitization, eczema and atopic asthma in children have been reported (3,4,24,25), but have not been evaluated extensively in the inner-city communities of the United States. We have measured endotoxin in the homes of 301 children living in NYC.…”

Mouse Allergen Exposure, Wheeze, and Atopy in the First Seven Years of Life

“…Dust samples collected at age 2-3 months in the living rooms were assayed for mouse and rat allergen by a competitive ELISA to determine the concentration of mouse urinary protein (MUP) and Rat n 1 in μg/g of dust (Greer Laboratories, Lenoir, NC, USA) as described previously (18,19). The lower limit of detection for the MUP and Rat n 1 assay was 0.25 μg/ g of dust.…”

“…The primary purpose was to assess the relationship between exposure to indoor allergens in early childhood and the subsequent development of asthma and allergic disease. In this cohort, we have recently reported that mouse allergen exposure is highly prevalent (18), and that mouse exposure in these infants is also associated with wheeze in the first year of life (19). To date, there are no prospective studies evaluating the role of early mouse allergen exposure in home environments and the development of wheezing, asthma and atopy in later life.…”