Bacterial Endotoxin Linked to 
Wheezing In Infants
Reuters Health Central News February 20, 2001

NEW YORK (Reuters Health) - Dust has long been the bane of meticulous housekeepers - and now there is another reason to banish it from the home. According to researchers, wheezing during the first year of life is more common in infants whose homes have high levels of bacterial endotoxin, an airway irritant that can be present in common house dust. 

Endotoxin is virtually everywhere in the environment, including house dust, but studies have clearly shown that endotoxin causes asthma to get worse, says Dr. Donald Milton from Harvard School of Public Health in Boston, Massachusetts, and associates. 

The authors measured endotoxin levels from dust in the homes of nearly 500 infants who were predisposed to asthma. The researchers compared the dust levels during the first three months of life with reports of wheezing before the infants' first birthdays. 

The findings are published in the February (2001) issue of the American Journal of Respiratory and Critical Care Medicine. 

Endotoxin levels were highest in the homes of families with a dog, and in homes with higher levels of cockroach protein in the dust, the report indicates. 

High levels of endotoxin in the living room brought a 33% increase in the risk of wheezing during the first year of life even after adjusting for other known risk factors such as smoking and the presence of a dog, the authors report. 

There was also a weak link between the level of endotoxin and the risk of repeated wheezing episodes during the first year of life, the researchers note. 

"Endotoxin is associated with increased risk of wheeze, and may promote persistent wheezing during the first year of life among children with a family history of allergy or asthma," the authors write. "The risks were independent of the effect of lower respiratory infection--one of the strongest risk factors for wheeze in infancy." 

"It remains to be determined," they conclude, "whether these infants are genetically more susceptible to endotoxin exposure or are at greater or lesser risk of developing asthma."

February 20, 2001 Issue of the NEW YORK (Reuters Health)