Research in action: Dr. Hong Chen

New ways of thinking about the health effects of air pollution

When it’s hot outside, we often think about air pollution and its effect on our lungs. Dr. Hong Chen is looking at the effects of air pollution in new ways, changing our understanding of its significance to human health.

In a groundbreaking study, Chen, a scientist at Public Health Ontario, and colleagues examined the relationship of air pollution to diabetes. “Risk of Incident Diabetes in Relation to Long-term Exposure to Fine Particulate Matter in Ontario, Canada” by Chen et al, published in the journal Environmental Health Perspectives, provides evidence that links long-term exposure of ambient fine particulate matter to the development of diabetes.

“We used to think of air pollution as something that shortened people’s lives, especially those with pre-existing diseases. We’re now discovering that long-term exposure to air pollution is related to the development of new cases of chronic disease,” said Chen. “This study adds to a growing body of scientific literature demonstrating that long-term exposure to ambient particulate matter may lead to an increased incidence of diabetes.”

The study by Chen and colleagues was the largest study undertaken that followed non-diabetic people to understand the possible relationship between air pollution exposure and the incidence of diabetes. The authors used health data from over 60,000 Canadian-born, non-diabetic, Ontario adults over the age of 35, and followed up on them for 15 years. At the end of the study, the authors found 6310 cases of incident diabetes. Notably, these results are in line with two previous studies: one from Los Angeles, California, and the other from the Ruhr district in Germany, cities with considerable air pollution. The study notes that the ambient level of fine particulate matter in Ontario was about half that in the two other studies, making it clear that even at the relatively low levels that are typically seen in Canada, air pollution can be linked to serious health effects.

The findings from this study may have broader public health implications, said Dr. Ray Copes, also a study author, and Chief, Environmental and Occupational Health, PHO. “In addition to diabetes, this research may add to our understanding of the possible effects of air pollution on multiple organ systems, including our hearts, lungs and endocrine glands.”

In fact, Chen is currently looking at the relationship between air pollution and cardiovascular disease. With partners at the Institute for Clinical Evaluative Sciences, PHO, Health Canada, Environment Canada, and several universities, he’s conducting a study to investigate whether long-term exposure to air pollution at levels below current standards or guidelines is associated with the development of cardiovascular disease and diabetes.

“We hope that this research will inform and assist policy-makers in making decisions about what levels of air pollution are acceptable for Canadians, given the wide range of health impacts,” said Chen.

“Risk of Incident Diabetes in Relation to Long-term Exposure to Fine Particulate Matter in Ontario, Canada,” by Chen H, Burnett RB, Kwong JC, Villeneuve P, Goldberg MS, Brook RD, van Donkelaar A, Jerrett M, Martin R, Brook J, Copes R is available at http://ehp.niehs.nih.gov/1205958/.