House Dust Endotoxin Association with Chronic Bronchitis and Emphysema

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 [Formula: see text] 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 [Formula: see text] , and CBE was reported by 8.2% of participants. In the adjusted analysis, one unit (EU/mg) increase in [Formula: see text]-transformed endotoxin concentrations was associated with a 27% increase in the odds of CBE diagnosis [[Formula: see text] (95% CI: 1.00, 1.61)] and a 78% increase in the odds of chronic bronchitis symptoms (defined as cough and phlegm for [Formula: see text] in a year for [Formula: see text]) [[Formula: see text] (95% CI: 1.01, 3.12)]. Sensitization to inhalant allergens ([Formula: see text]) modified the relationship between endotoxin and CBE diagnosis, with stronger associations observed in sensitized participants [[Formula: see text] (95% CI: 1.72, 3.50) for a unit increase in [Formula: see text]-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