August 20, 2012: Air Pollution Associated with Asthma Development Among Young Children

–Exposure to pyrene increases odds of non-atopic asthma development–

NEW YORK (August 20, 2012) – High exposure to air pollution in the womb and continuing exposure during early childhood increase risk for development of non-atopic asthma, according to a study by researchers at Columbia Center for Children’s Environmental Health (the Center) at the Mailman School of Public Health, Department of Environmental Health Sciences and Columbia University’s College of Physicians and Surgeons.

Pyrene -a harmful component of air pollution- is a type of polycyclic aromatic hydrocarbon (PAH) that most commonly results from traffic emissions, burning of heating oil and indoor air pollution sources such as environmental tobacco smoke. Previous research by the Center has found an association between prenatal exposure to PAHs and respiratory problems and asthma in young children. Most research on asthma has focused on atopic asthma-asthma that is associated with an allergic response-yet non-atopic asthma accounts for an estimated 31-59% of childhood asthma cases. The present study addresses this research gap.

In this study, published online August 17, 2012 in Annals of Asthma, Allergy & Immunology, Kyung Hwa Jung, PhD, lead author and Center researcher, and Rachel L. Miller, M.D., Center Deputy Director and senior researcher, tested the association between continued exposure to pyrene and other PAHs and asthma and asthma-related symptoms in children at ages 5-6. They theorized that the relationship would vary depending on whether a child was atopic or not (i.e. tested positive for allergies to common indoor allergens such as dust mite, cockroach, cat, dog and mouse).

Data were collected from 349 mother-child pairs from the Center’s Mothers & Newborns study in Northern Manhattan and the South Bronx. During pregnancy, the mothers wore personal air monitors for 48 hours to evaluate prenatal PAH exposure. When the children were 5-6 years old, air samples were collected from the home for two weeks. Asthma and respiratory symptoms were evaluated through two validated questionnaires. Blood samples of the children were tested for allergic response to common indoor allergens.

Findings show that 28% of children had high exposure to pyrene during the mothers’ pregnancy and when the child was 5-6 years old. Among non-atopic children – those who were not sensitized to indoor allergens – high pyrene exposure was associated with increased odds of wheeze, asthma, asthma medication use, and emergency room visits. These findings indicate that exposure to pyrene could be a key factor in the development of non-atopic asthma.

Although more research is needed to fully understand the relationship between exposure to pyrene and asthma, this study is an important first analysis of the effect of prenatal and postnatal pyrene exposure on non-atopic asthma among young children. Such research is important to increase our understanding of a common form of asthma and to inform prevention efforts. Evidence indicating risk factors for non-atopic asthma, such as urban air pollution, will allow for the creation of targeted interventions.

This study was supported by the National Institute of Environmental Health Sciences, the U.S. Environmental Protection Agency, and private foundations.

Additional co-authors included Beizhan Yan, Kathleen Moors, Steven N Chillrud, Matthew Perzanowski, Robin M Whyatt, Lori Hoepner, Inge Goldstein, Bingzhi Zhang, David Camann, Patrick L Kinney, and Frederica P Perera, Center Director.

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