Synergistic Association of House Endotoxin Exposure and Ambient Air Pollution with Asthma Outcomes

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Tuesday, April 9, 2019
Angelico Mendy
Jesse Wilkerson
Pӓivi M. Salo
Charles H. Weir
Lydia Feinstein
Darryl C. Zeldin
Peter S. Thorne
Journal Title: 
American Journal of Respiratory and Critical Care Medicine

House endotoxin and ambient air pollution are risk factors for asthma; however, the effects of their co-exposure on asthma are not well characterized. Objectives: To examine potential synergistic associations of co-exposure to house dust endotoxin and ambient air pollutants with asthma outcomes. Methods: We analyzed data from 6,488 participants in National Health and Nutrition Examination Survey (NHANES) 2005-2006. Dust from bedding and bedroom floor was analyzed for endotoxin content. The Community Multiscale Air Quality (CMAQ) and Downscaler (DS) data were used to determine annual average particulate matter ≤2.5 μm (PM2.5), ozone (O3), and nitrogen dioxide (NO2) exposures at participants’ residential locations. The associations of the co-exposures with asthma outcomes were assessed and tested for synergistic interaction. Results: In adjusted analysis, PM2.5 (CMAQ) (OR 1.12, 95% CI: 1.07-1.18), O3 (DS) (OR 1.07, 95% CI: 1.02-1.13), and log1010-NO2 (CMAQ) (OR 3.15, 95% CI: 1.33-7.45) were positively associated with emergency room (ER) visits for asthma in the past 12 months. Co-exposure to elevated levels of house dust endotoxin and PM2.5 (CMAQ) was synergistically associated with the outcome, increasing the odds by 5-fold (OR 5.01, 95% CI: 2.54-9.87). A synergistic association was also found for co-exposure to higher concentrations of endotoxin and NO2 in children (OR 3.45, 95% CI: 1.65-7.18). Conclusions: Co-exposure to elevated levels of residential endotoxin and ambient PM2.5 in all participants and NO2 in children is synergistically associated with increased ER visits for asthma. Therefore, decreasing exposure to both endotoxin and air pollution may help reduce asthma morbidity.


Mendy, Angelico, Jesse Wilkerson, Pӓivi M. Salo, Charles H. Weir, Lydia Feinstein, Darryl C. Zeldin, and Peter S. Thorne. "Synergistic Association of House Endotoxin Exposure and Ambient Air Pollution with Asthma Outcomes." American journal of respiratory and critical care medicine ja (2019).