Your Heart on Air Pollution: An Olympic Case Study

By Nadja Popovich

China's radical blue-sky measures during the 2008 Olympics actually improved Beijingers' cardiovascular health -- if only for a few weeks.

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Aly Song/Reuters

In 2008, the Chinese government conducted one of the largest real-time environmental experiments ever undertaken: In order to get air quality up to par for the summer Olympics in Beijing--in of the world's most polluted metropolis--the government halved the number of cars allowed to drive the city's roads, shut down coal-burning factories in the area, and halted construction projects, among other efforts. And it worked. Air quality met the International Olympic Committee's (IOC) standards during the Olympics and subsequent Paralympic Games; both Athletes and Beijing residents could breathe a little easier - at least for a while.

U.S. Olympic distance runner Amy Yoder Begley, who had previously visited Beijing, declared air quality "better than expected" upon arriving for the 2008 games. The IOC was pleased too. "I think, objectively, we can say that the Chinese authorities have done everything that is feasible and humanly possible to solve the situation or to address the situation," Olympic Committee chief Jacques Rogge reported during a press conference. "What they have done is extraordinary."

After the games came to an end, however, many of the temporary pollution-reducing measures were relaxed, and pollution levels climbed once more.

Although the period of blue skies in Beijing may have been fleeting, researchers from the University of Southern California (USC) and colleagues have found that even such a small window of cleaner air may have proved useful for residents' cardiovascular health. That's according to a new study published yesterday in the Journal of the American Medical Association.

"Heart disease in on the rise everywhere in the world - especially in the developing world," says Dr. Junfeng Zhang, Professor of Environmental and Global Health at USC, and senior author on the study. "So, we thought that this drastic a change in air quality in a relatively short period of time could provide a unique experimental condition to really detect biological changes relevant to cardiovascular health."

For the study, Zhang and colleagues recruited 125 healthy, young people, all of whom worked at a local Beijing hospital. They measured several markers of heart health in study participants before, during, and after the Olympic period - most notably the von Willebrand factor and soluble P-selectin (sCD62P), indicators of blood clotting and noted precursors to cardiovascular events such as stroke and heart attack. Zhnag's team also measured daily concentration of air pollutants.

"We hypothesized that biomarkers of cardiovascular health would change as air pollution levels change," says Zhang. "And that is, in fact, what we found." As pollution levels dropped, so did indicators of cardiovascular risk in study participants. As pollution levels rose back to pre-Olympic levels, indicators rose right alongside.

While the link between cardiovascular disease and air pollution has long been acknowledged by the American Medical Association, this study is the first to directly look at the underlying mechanisms by which air pollution affects the heart.

"[Other] epidemiological studies have linked air pollution, especially fine particulate matter - 'soot' -- with adverse cardiovascular outcomes, but these studies seldom shed any light on biological mechanisms underlying this association," said Dr. John M. Balmes, Professor of Pulmonary Medicine, University of California San Francisco, responding to the study in an email to the Atlantic. "This study took advantage of the decreased air pollution of the Olympics period in Beijing to investigate potential mechanisms of the adverse cardiovascular effects."

But beyond understanding the mechanisms by which air pollution may impact cardiovasular health, Zhang says there's another important take-away point in his study: air pollution doesn't discriminate by age.

"'I'm young, I'm super healthy, I shouldn't worry about those things, is how young people think," Zhang says. "But this study shows that even if you're young and healthy, your physiology can actually detect the impact of air pollution."

Most governments would not be able to institute the sorts of radical pollution-reducing measures undertaken by China in 2008, but Zhang says there is still hope that even short-term and incremental reprieves from polluted air can help our hearts.

"This study can only answer a few questions we have about the link between air pollution and cardiovascular health. But I think the important thing is that even with these sorts of short term changes - if your body gets only a brief break from the chronic burden of air pollution exposure - it can still do some good for your health overall," he says.

This article available online at:

http://www.theatlantic.com/health/archive/2012/05/your-heart-on-air-pollution-an-olympic-case-study/257236/