Household endotoxin levels have been variably linked to asthma and atopy. We sought to determine the association between household endotoxin levels and food allergen sensitization in a large national cohort.
We studied 6,963 participants from the 2005-2006 National Health and Nutrition Examination Survey (NHANES). House dust endotoxin was collected from the bedroom, and serum-specific IgE for milk, egg, and peanut were measured. Log-transformed endotoxin level and specific food allergen sensitization (sIgE>=0.35 kU/L) were fitted into logistic regression models using STATA11.
The geometric mean of household endotoxin in this large US cohort was 15.5 EU/mg (standard error 0.5 EU/mg). The prevalence of food allergen sensitization varied by specific food: milk 5.7%, egg 4.0%, and peanut 7.9%. The unadjusted model revealed that a 10-fold increment in endotoxin was associated with sensitization to milk (OR 1.8, 95%CI 1.3-2.3) and egg (OR 1.4, 95%CI 1.04-1.8) but not peanut (OR 1.1, 95%CI 0.9-1.4). Multivariable logistic regression models controlled for identified confounders including age, country of birth, total people in household, race, history of wheezing, and US region demonstrated that household endotoxin levels remained positively associated with sensitization to milk (OR 1.7, 95%CI 1.2-2.1) and egg (OR 1.4, 95%CI 1.01-1.9) but not peanut (OR 0.98, 95%CI 0.8-1.2).
Increasing household endotoxin levels is associated with higher odds of milk and egg sensitization. Participants with allergies likely have an altered responsiveness to microbial components leading to allergic disease. This effect of endotoxin is beneficial for understanding how environmental factors play a role in food allergies.