Study: High Allergen Levels in U.S. Homes
Microscopic particles are found in dust, bedding, floors
WEDNESDAY, Dec. 7, 2005 (HealthDay News) -- Bacterial allergens called endotoxins are common in house dust in American homes and pose a major asthma risk, a new study finds.
Endotoxins are toxic substances found in the outer membrane of some forms of bacteria. Past studies have shown that exposure to endotoxins can cause lung inflammation. Common indoor sources of endotoxins include dust, pets, humidifiers, and pests.
"This study clearly demonstrates significant relationships between household endotoxin and diagnosed asthma, recent asthma symptoms, current use of asthma medications and wheezing," researcher Peter S. Thorne, of the University of Iowa Environmental Health Sciences Center, said in a prepared statement.
His team evaluated nearly 2,500 people in 831 homes and collected 2,552 dust samples from various locations within the homes: Bedroom floors, bedding, family room floors, sofa surfaces and kitchen floors.
The strongest relationship between asthma, asthma medication and wheezing came from endotoxins in bedroom bedding and floor dust. This relationship was observed in adults, but not in children. The highest endotoxin concentrations were found in kitchen and living room floor dust, while the lowest concentrations were in bedding, including mattresses and pillows.
The findings appear in the December issue of the American Journal of Respiratory and Critical Care Medicine.
The U.S. National Institute of Environmental Health Sciences has more about allergy and asthma prevention.