Chris Carlsten, MD MPH is an Associate Professor at the University of British Columbia, where he holds the endowed Chair in Occupational and Environmental Lung Disease. He is also the director of the Occupational Lung Disease Clinic at Vancouver General Hospital's Lung Centre. His latest findings on the effects of diesel exhaust and other pollution on asthma have the potential to influence public policies on pollution.
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Docs Talk: Your lab has been studying the effects of air pollution on human lungs. Tell us a bit about what you've found so far.
Dr. Carlsten: We wanted to know why different people respond differently to air pollution, even within the same geographical area. Focused specifically on the lungs, we have followed a large group of people—both children and adults—and conducted observational and experimental studies to see how they react to air pollution, specifically diesel exhaust.
There are, in fact, several reasons behind the variation in response to air pollution, including human behavior (for example, whether a person exercises or not) and time spent in "microenvironments" where air pollution is much more concentrated. But the factor we're currently focused on is a person's genetic makeup. In short, certain people have gene variants that make them more likely to develop asthma when exposed to air pollution.
DT: How common are the gene variants that make us more susceptible to air pollution?
Dr. Carlsten: We studied over 5,000 children—a larger group than anyone has ever studied in this way—and found these gene variants in approximately 10 percent of children. The children with the gene variant had a 50 per cent increased risk of developing asthma. Children with both the gene variant and exposure to higher air pollution levels have an even higher risk of developing asthma.
DT: What are the implications of these findings?
Dr. Carlsten: Our research will add to a larger understanding of the effects of air pollution, which will ultimately contribute to public policy. These particular findings are very important because society, supported by government, has a responsibility to protect its most vulnerable members from the effects of air pollution.
Historically, research has looked at populations on average rather than focusing on highly susceptible groups within those populations. Because these gene variants are relatively common, and because air pollution is nearly ubiquitious, our findings suggest that many thousands of children worldwide are at risk from this dangerous combination of gene variants and air pollution.
We believe that air pollution standards and related regulations should be made with some sensitivity towards those who are particularly affected by pollution, by no fault of their own.