house dust increases risk for asthmaEndotoxin is a heat stable toxin in the wall of certain bacteria cells, and it is the endotoxin in house dust that increases the risk for asthma sufferers. When the bacteria is inhaled and disintegrates, the toxin is released. A study published in the American Journal of Respiratory and Critical Care Medicine in April 2005 shows that exposure to endotoxins significantly affects airway inflammation and wheezing. The result is that there is a clear relationship between households with increased endotoxin levels, and household residents with diagnosed asthma, recent asthma symptoms, wheezing, and use of asthma medication. For the study, the research team of Prof. Peter S. Thorne from the Environmental Health Sciences Research Center at the University of Iowa evaluated 2,456 residents in 831 homes throughout the US. Dust samples were collected from five locations within the homes: kitchen floors, sofa surface, bedding, bedroom floors, living room floors. The relationship between increasing endotoxin levels and asthma symptoms, wheezing and use of asthma medication was the strongest for dust from bedding and bedroom floors. The highest concentrations of endotoxin in household dust were found in the living room and the kitchen floors.