The researchers found that all dust samples contained detectable levels of endotoxin. The average concentration of endotoxin ranged from 80.5 units per milligram of dust on kitchen floors to 18.7 on bedding. Family room floors had endotoxin concentrations of 63.9 units per milligram of dust; sofas had concentration levels at 44.8; and 35.3 units on bedroom floors.
“Interestingly, endotoxin exposure worsens asthma symptoms in adults, regardless of whether an individual has allergies or not" said Peter S. Thorne, Ph.D., a researcher at the University of Iowa and lead author on the paper. "This suggests that exposure to endotoxin increases asthma risk even in non-allergic individuals."
Since the mid 1960s, researchers knew that house dust contains endotoxin, but it is only within the last five years that they began to understand the impact of household endotoxin on human health. Knowing what triggers asthma, whether it is endotoxins or something else, may help a physician better prevent or treat symptoms.
“This study implies that it is not just the concentration of the endotoxin that matters,?added Dr. Schwartz, Director of NIEHS. “Understanding how factors such as duration of exposure, timing of the exposure, and genetic factors, contribute to the development of diseases like asthma will lead to new insights into how to prevent and treat this important disease.?NIEHS is implementing new studies to better understand the role that the indoor environment plays in the development and severity of asthma.
NIEHS, a component of the National Institutes of Health, supports research to under