Children growing up in a stressful household condition are prone to lung-damaging effects of traffic-related pollution (TRP), says research from the Keck School of Medicine of the University of Southern California (USC).
"This is the first study demonstrating that growing up in a stressful household was associated with larger traffic pollution-induced lung deficits in healthy children compared to low stress households," said lead researcher Talat Islam, MBBS, assistant professor in the Division of Environmental Health at Keck School of Medicine.
Dr. Islam and colleagues administered a validated stress questionnaire, the Perceived Stress Scale (PSS), to the parents of nearly 1,400 children who participated in the USC Children's Health Study in Southern California.
The researchers did not observe any statistically significant associations between parental stress alone and lung function levels in children. However, they found that as levels of traffic-related pollution increased among children who grew up in high-stress households, lung function decreased, but there was no corresponding lung effect in low- stress households.
"Children in this age group spend almost one-third of their day-time hours at school so exposure at school is an important contributor to total exposure," said Dr. Islam.
"Perhaps children maintain the chronic and systemic effect of stress from their home environments as they go to school, further modifying their response to traffic exposure."
"One possible explanation for the stress-related pattern of TRP respiratory effects is the biological pathways common to effects of TRP and stress."
"Like air pollution, stress has been linked to both inflammation and oxidative damage at the cellular level, so this may explain the association," added Dr. Islam.
The results will appear online ahead of the print edition of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.