Asthma can be triggered by exposure to endotoxins in the house, according to the American Journal of Respiratory and Critical Care Medicine study. Humidifiers, pests, dust, pets, and outdoor air are common sources of endotoxins, according to the University of Iowa's Dr. Peter S. Thorne.
The researchers evaluated 2,456 residents in 831 homes selected to represent the demographic characteristics of the U.S. population. They took 2,552 house dust samples from five locations within the homes, including bedroom floors, bedding, family room floors, sofa surfaces, and kitchen floors.
"This study clearly demonstrates significant relationships between household endotoxin and diagnosed asthma, recent asthma symptoms, current use of asthma medications, and wheezing. No effect was observed of allergy status on the relationship between endotoxin and asthma outcomes," said Dr. Thorne.
"This suggests that current endotoxin exposure may have little impact on allergy status and that airway inflammation is the most significant effect of endotoxin exposure in a cross-section of the population," Dr. Thorne added.
The researchers also found strong relationship between asthma, asthma medications, and wheezing came from endotoxin levels in bedroom floor and bedding dust. However, the effects were observed only in adults and not in children. The endotoxin concentrations were highest in kitchen and living room floor dust, and lowest in the case of bedding.
"The mean concentration of endotoxin in the kitchen floor dust was 2.3-fold higher than bedroom floor dust and 4.3-fold higher than bedding dust," said Dr. Thorne.