(Ivanhoe Newswire) -- Man's best friend could be a worst enemy for kids with asthma. New research reveals having a dog in the home may worsen the response to air pollution of asthmatic kids.

In a study out of the University of Southern California in Los Angeles, investigators found children with dogs had significantly increased cough, phlegm production and bronchitis responses to the air pollutants. This wasn't true for kids who didn't live with pets -- or had cats only.

Researchers report, "Further work is needed to determine what it is about dogs that may increase an asthmatic child's response to air pollution." They add this link between air pollution and dogs may be due to increased levels of endotoxin, which is more common in homes where there is a dog.

They write, "Cats are highly allergenic, and children with asthma are often allergic to cats. Therefore if an allergen were enhancing the lung's response to air pollution, we'd be more likely to see an association with cats. But in this study we see an effect of air pollution in homes with dogs, so we think endotoxin exposure is a more likely explanation for our results than allergen exposure."
 

SOURCE: Environmental Health Perspectives, published online Aug. 29, 2006