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Background: Endotoxin has been reported to be associated with chronic bronchitis or emphysema (CBE) at high occupational exposures. However, whether levels found in domestic environments have similar effects is unknown. Objectives: We aimed to study the association between house dust endotoxin and CBE in a sample representative of the U.S. population. Methods: We analyzed data from 3,393 participants [greater than or equal to] 20 y old from the National Health and Nutrition Examination Survey (NHANES) 2005-2006. House dust from bedding and from bedroom floors was analyzed for endotoxin content. NHANES participants received questionnaires and underwent examination as well as extensive laboratory testing. Logistic regression was used to examine the association of endotoxin levels with CBE diagnosis and symptoms, adjusting for covariates. The survey design and weights were applied so that estimates were nationally representative and so that statistical inferences were made appropriately. Results: The median endotoxin concentration in house dust was 14.61EU/mg dust, and CBE was reported by 8.2% of participants. In the adjusted analysis, one unit (EU/mg) increase in [log.sub.10]-transformed endotoxin concentrations was associated with a 27% increase in the odds of CBE diagnosis [OR = 1.27 (95% CI: 1.00, 1.61)] and a 78% increase in the odds of chronic bronchitis symptoms (defined as cough and phlegm for [greater than or equal to] 3 mo in a year for [greater than or equal to] 2 y) [OR = 1.78 (95% CI: 1.01, 3.12)]. Sensitization to inhalant allergens (p = 0.001) modified the relationship between endotoxin and CBE diagnosis, with stronger associations observed in sensitized participants [OR = 2.46 (95% CI: 1.72, 3.50) for a unit increase in [log.sub.10]-endotoxin]. Conclusions: In a population-based sample of U.S. adults, endotoxin levels in homes were associated with a self- reported history of CBE diagnosis and chronic bronchitis symptoms, with stronger associations among people sensitized to inhalant allergens. https://doi.org/10.1289/EHP2452, Introduction Chronic bronchitis is a common condition that affects 10 million Americans (American Lung Association 2014; Kim et al. 2015). The condition is characterized by airway inflammation and airway remodeling [...]

BACKGROUND: The peripheral leukocyte count is a biomarker of inflammation and is associated with human all-cause mortality. Although causes of acute leukocytosis are well-described, chronic environmental determinants of leukocyte number are less well understood. OBJECTIVES: We investigated the relationship between house dust endotoxin concentration and peripheral leukocyte counts in human subjects. METHODS: The endotoxin-leukocyte relationship was evaluated by linear regression in the National Health and Nutrition Examination Survey (NHANES) 2005-2006 (n = 6,254) and the Agricultural Lung Health Study (ALHS; n = 1,708). In the ALHS, we tested for a gene [Toll-like Receptor 4 (TLR4), encoding the endotoxin receptor]-by-environment interaction in the endotoxin-leukocyte relationship using regression models with an interaction term. RESULTS: There is a statistically significant, positive association between endotoxin concentration and total leukocyte number [estimated change, 0.186 x [10.sup.3]/[micro]L (95% CI: 0.070, 0.301 x [10.sup.3]/[micro]L) per 10- fold change in endotoxin; p = 0.004) in the NHANES. Similar positive associations were found for monocytes, lymphocytes, and neutrophils. Stratified analyses revealed possible effect modification by asthma and chronic obstructive pulmonary disease. We observed similar associations in the ALHS. For total leukocytes, there was suggestive evidence in the ALHS of a gene-by-environment interaction for minor allele carrier status at the TLR4 haplotype defined by rs4986790 and rs4986791 (interaction p = 0.15). CONCLUSIONS: This is, to our knowledge, the first report of an association between house dust endotoxin and leukocyte count in a national survey. The finding was replicated in a farming population. Peripheral leukocyte count may be influenced by residential endotoxin exposure in diverse settings. https://doi.org/10.1289/EHP661, Introduction Leukocytes are effectors and biomarkers of inflammation. The total count of white blood cells (WBCs) in the circulation is associated with coronary, cancer, and all-cause mortality in human subjects [...]

Background: Dust mite allergens can induce allergic sensitization and exacerbate asthma symptoms. Although dust mite reduction and control strategies exist, few asthmatics employ them.Objectives: We examined whether an in-home test kit, which quantifies dust mite allergen levels, resulted in behavioral changes in implementation and maintenance of mite reduction strategies and helped reduce allergen levels in homes of dust mite-sensitive children.Methods: We enrolled 60 households of children aged 5–15 with parent-reported dust mite allergy into a randomized controlled trial. Intervention homes (N = 30) received educational material about reducing dust mites and test kits at 1, 2, 5 and 8 months. Control homes (N = 30) received only educational material. At baseline, 6 and 12 months, study staff visited all homes, collected dust samples from three locations and obtained information about parents’ mite reduction behaviors by questionnaire. Allergen concentrations (Der f 2/Der p2) in dust were assessed by immunoassays. After adjusting for visit and location, allergen concentrations in intervention and control homes were compared using mixed effects model analysis.Results: In the intervention homes, allergen concentrations in the child’s bedroom and living room floors were significantly reduced over time compared to control homes. Although not all location-specific differences in allergen concentrations were statistically significant, combining data across locations, there was a differential reduction in allergen concentrations in the intervention group versus the control group (p = 0.02).Conclusion: The use of in-home test kits along with education may beneficially influence behaviors and attitudes toward dust mite reduction strategies and help reduce residential dust mite allergen levels. [ABSTRACT FROM PUBLISHER]