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

Department of Epidemiology, Columbia University, New York, New York, United States
Journal of Allergy and Clinical Immunology (Impact Factor: 11.48). 05/2006; 117(5):1082-9. DOI: 10.1016/j.jaci.2005.12.1348
Source: PubMed


An inverse association between domestic exposure to endotoxin and atopy in childhood has been observed. The relevance of this aspect of the hygiene hypothesis to US inner-city communities that have disproportionately high asthma prevalence has not been determined.
To measure endotoxin in the dust from inner-city homes, evaluate associations between endotoxin and housing/lifestyle characteristics, and determine whether endotoxin exposure predicted wheeze, allergic rhinitis, and eczema over the first 3 years of life.
As part of an ongoing prospective birth cohort study, children of Dominican and African-American mothers living in New York City underwent repeated questionnaire measures. Dust samples collected from bedroom floors at age 12 or 36 months were assayed for endotoxin.
Among the samples collected from 301 participants' homes, the geometric mean endotoxin concentration (95% CI) was 75.9 EU/mg (66-87), and load was 3892 EU/m2 (3351-4522). Lower endotoxin concentrations were associated with wet mop cleaning and certain neighborhoods. Endotoxin concentration correlated weakly with cockroach (Bla g 2: r = 0.22, P < .001) and mouse (mouse urinary protein: r = 0.28; P < .001) allergens in the dust. Children in homes with higher endotoxin concentration were less likely to have eczema at age 1 year (odds ratio, 0.70 [0.53-0.93]) and more likely to wheeze at age 2 years (odds ratio, 1.34 [1.01-1.78]). These associations were stronger among children with a maternal history of asthma.
Endotoxin levels in this inner-city community are similar to those in nonfarm homes elsewhere. In this community, domestic endotoxin exposure was inversely associated with eczema at age 1 year, but positively associated with wheeze at age 2 years.
Endotoxin exposure in the inner-city community may be related to wheeze in the early life; however, given the inverse association seen with eczema, the long-term development of allergic disease is still in question.

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Available from: Peter S Thorne, Oct 09, 2015
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    • "Endotoxin is ubiquitous in both indoor and outdoor environments . Several studies have been carried out worldwide to assess endotoxin levels through measurement of settled house dust (Heinrich et al., 2001; Gereda et al., 2001; Su et al., 2002; Perzanowski et al., 2005; Tavernier et al., 2006; Thorne et al., 2009; Madsen et al., 2012; Sordillo et al., 2011; Moniruzzaman et al., 2012; Chen et al., 2012). However, relatively few studies have been conducted to measure endotoxin levels in the ambient air (Park et al., 2000; Heinrich et al., 2003; Morgenstern et al., 2005; Sebastian et al., 2006; Dales et al., 2006; Madsen, 2006; Wheeler et al., 2011b; McNamara et al., 2013; Pavilonis et al., 2013) and simultaneously in both dust and air media (Park et al., 2001; Singh et al., 2011; Mazique et al., 2011; Barnig et al., 2013). "
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    ABSTRACT: Exposure to coarse particulate matter (PM), i.e., particles with an aerodynamic diameter between 2.5 and 10 μm (PM10-2.5), is of increasing interest due to the potential for health effects including asthma, allergy and respiratory symptoms. Limited information is available on indoor and outdoor coarse PM and associated endotoxin exposures. Seven consecutive 24-h samples of indoor and outdoor coarse PM were collected during winter and summer 2010 using Harvard Coarse Impactors in a total of 74 Edmonton homes where no reported smoking took place. Coarse PM filters were subsequently analyzed for endotoxin content. Data were also collected on indoor and outdoor temperature, relative humidity, air exchange rate, housing characteristics and occupants’ activities. During winter, outdoor concentrations of coarse PM (median = 6.7 µg/m3, interquartile range, IQR = 3.4–12 µg/m3) were found to be higher than indoor concentrations (median 3.4 µg/m3, IQR = 1.6–5.7 µg/m3); while summer levels of indoor and outdoor concentrations were similar (median 4.5 µg/m3, IQR = 2.3–6.8 µg/m3, and median 4.7 µg/m3, IQR = 2.1–7.9 µg/m3, respectively). Similar predictors were identified for indoor coarse PM in both seasons and included corresponding outdoor coarse PM concentrations, whether vacuuming, sweeping or dusting was performed during the sampling period, and number of occupants in the home. Winter indoor coarse PM predictors also included the number of dogs and indoor endotoxin concentrations. Summer median endotoxin concentrations (indoor: 0.41 EU/m3, outdoor: 0.64 EU/m3) were 4-fold higher than winter concentrations (indoor: 0.12 EU/m3, outdoor: 0.16 EU/m3). Other than outdoor endotoxin concentrations, indoor endotoxin concentration predictors for both seasons were different. Winter endotoxin predictors also included presence of furry pets and whether the vacuum had a high efficiency particulate air (HEPA) filter. Summer endotoxin predictors were problems with mice in the previous 12 months and mean indoor relative humidity levels.
    Atmospheric Environment 04/2014; 92. DOI:10.1016/j.atmosenv.2014.04.025 · 3.28 Impact Factor
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    • "Endotoxin, a lipopolysaccharide present in the outer membrane of gram-negative bacteria, downregulates Th2 cytokine production7). However, in inner-city communities, domestic endotoxin exposure was positively associated with wheeze in children at 2 years of age8). One unanswered question is whether the greater levels of endotoxin associated with an inner-city lifestyle can explain the higher prevalence of asthma relative to that observed in rural areas. "
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    ABSTRACT: A complex interplay between genetic and environmental factors partially contributes to the development of allergic diseases by affecting development during prenatal and early life. To explain the dramatic increase in the prevalence of allergic diseases, the hygiene hypothesis proposed that early exposure to infection prevented allergic diseases. The hygiene hypothesis has changed to the microbial hypothesis, in which exposure to microbes is closely linked to the development of the early immune system and allergic diseases. The intestinal flora may contribute to allergic disease through its substantial effect on mucosal immunity. Based on findings that exposure to microbial flora early in life can change the Th1/Th2 balance, thus favoring a Th1 cell response, probiotics may be beneficial in preventing allergic diseases. However, evidence from clinical and basic research to prove the efficacy of probiotics in preventing allergy is lacking. To date, studies have yielded inconsistent findings on the usefulness of probiotics in allergic diseases. It is difficult to demonstrate an exact effect of probiotics on asthma, allergic rhinitis, and food allergy because of study limitations, such as different first supplementation period, duration, different strains, short follow-up period, and host factors. However, many studies have demonstrated a significant clinical improvement in atopic dermatitis with the use of probiotics. An accurate understanding of the development of human immunity, intestinal barrier function, intestinal microbiota, and systemic immunity is required to comprehend the effects of probiotics on allergic diseases.
    Korean Journal of Pediatrics 09/2013; 56(9):369-376. DOI:10.3345/kjp.2013.56.9.369
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    • "Living in homes with moderately elevated concentrations of endotoxin in house dust has been associated with increased risk of wheezing in infants (Park et al. 2001). However, other studies suggest that exposure to endotoxin may decrease risk of childhood atopy (Perzanowski et al. 2006). Overall, the literature to date suggests that exposure to house dust endotoxin early in life may protect from atopic sensitization and IgE-mediated diseases but remains a risk factor for wheezing in infancy (Eder and von Mutius 2004). "
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    ABSTRACT: The hurricanes and flooding in New Orleans, Louisiana, in October and November 2005 resulted in damp conditions favorable to the dispersion of bioaerosols such as mold spores and endotoxin. Our objective in this study was to assess potential human exposure to bioaerosols in New Orleans after the flooding of the city. A team of investigators performed continuous airborne sampling for mold spores and endotoxin outdoors in flooded and nonflooded areas, and inside homes that had undergone various levels of remediation, for periods of 5-24 hr during the 2 months after the flooding. The estimated 24-hr mold concentrations ranged from 21,000 to 102,000 spores/m3 in outdoor air and from 11,000 to 645,000 spores/m3 in indoor air. The mean outdoor spore concentration in flooded areas was roughly double the concentration in nonflooded areas (66,167 vs. 33,179 spores/m3 ; p < 0.05) . The highest concentrations were inside homes. The most common mold species were from the genera of Cladosporium and Aspergillus/Penicillium ; Stachybotrys was detected in some indoor samples. The airborne endotoxin concentrations ranged from 0.6 to 8.3 EU (endotoxin units) /m3 but did not vary with flooded status or between indoor and outdoor environments. The high concentration of mold measured indoors and outdoors in the New Orleans area is likely to be a significant respiratory hazard that should be monitored over time. Workers and returning residents should use appropriate personal protective equipment and exposure mitigation techniques to prevent respiratory morbidity and long-term health effects.
    Environmental Health Perspectives 10/2006; 114(9):1381-6. DOI:10.1289/ehp.9198 · 7.98 Impact Factor
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