Parental stress, in combination with exposure to traffic-related pollution, is a toxic cocktail that boosts the likelihood of children developing asthma.

The University of Southern California (USC) tracked 2,497 children with no history of respiratory problems and examined whether or not they developed asthma in kindergarten or first grade.

They found that parental stress alone did not increase the likelihood of the children developing asthma, but in the presence of pollution from nearby traffic the children’s asthma rates increased at a higher level than that of children exposed only to pollution.

“Air pollution can promote inflammatory responses in the airways of the lung, which is a central feature of asthma,” principal USC investigator Rob McConnell said in a university publication. “Stress may also have pro-inflammatory effects and this may help explain why the two exposures together were important.”

The study was conducted by the Keck School of Medicine at USC and will be published in the upcoming edition of the Proceedings of the National Academy of Sciences.

To read the full report, visithttp://uscnews.usc.edu/health/stress_and_pollution_up_risk_for_children.html.