Urban air increasingly linked to heart disease
Smog might not be the first thing that comes to mind when you think about cardiovascular disease, but mounting evidence shows the two are related.
With air pollution being a major problem around the globe, the risk of heart attack may go up with every breath you take.
“You can sum it up like this: more pollution, more major adverse cardiac events,” says François Reeves, interventional cardiologist and author of the new book Planet Heart: How an Unhealthy Environment Leads to Heart Disease, on the line from his Montreal home.
“Pollution of the city is as toxic as cigarette smoke. It has different stuff in it, but the difference is that with pollution, you get it all through your life, from your birth to your death. If you live in a polluted milieu, as soon as you’re a baby you’ll take it in through every breath.”
Reeves, who’s also an associate professor of medicine in the University of Montreal’s department of environmental health, says there is a growing body of research linking air pollution and heart disease.
According to a March 25 release by the World Health Organization (WHO), exposure to air pollution accounted for seven million deaths worldwide in 2012, which is one in eight of total global deaths that year and more than double previous estimates. The study confirmed that air pollution is the greatest contributor to the burden of disease from the environment. Exposure is a more important risk factor for conditions such as ischemic heart disease and stroke than previously thought.
Another WHO report, from 2008 and called Atlas of Health in Europe, found that nations in the former Soviet bloc have cardiovascular-disease death rates up to 10 times higher than those in Western Europe: In France and Norway, the rate among men aged 25 to 64 is roughly 70 in 100,000 people, while in Ukraine it’s 600 and in Russia, it’s 762.
“I was blown away by those numbers,” Reeves says. “We know the classical and well-demonstrated risk factors for heart disease, like smoking and obesity and inactivity. But that’s when I realized the environment has a huge impact.”
Michael Brauer, a UBC professor in the faculty of medicine’s school of population and public health, says that poor air quality is an overlooked risk factor for disease in general.
“There are 3.2 million deaths per year from [outdoor] air pollution, and 1.2 million of those are in China alone,” Brauer says on the line from his office. “There are definitely parts of the world that are worse off than others. Conservative estimates from Canada are around 7,000 deaths per year.
“Globally, air pollution ranks among one of the top risk factors for disease,” says Brauer, who contributed to the WHO’s Global Burden of Disease study. “People are quite aware of diet and high blood pressure, but this is something people just don’t appreciate.”
Smog consists of numerous contaminants, but it is high concentrations of particulate matter that are associated with heart disease and stroke as well as respiratory illness and certain cancers. These particles cause the greatest health risk because they are tiny and once inhaled can lodge deeply in the lungs.
“Exposure is also constant,” Brauer adds. “You may be exposed to a virus when somebody sneezes, and it’s done with. But you’re breathing air pollution 24/7 if you’re living in a polluted area.”
Vancouver is, indeed, one of the greenest major cities in the world, if not the greenest, Brauer notes. But local residents can’t relax altogether about the health effects of air pollution. The adverse health effects of particulate air pollution, even at relatively low levels, remain a global public-health concern.
“We’re nowhere near the levels of the most polluted places like Beijing, Shanghai, and Delhi, but, having said that, we can still measure impacts of air pollution on health,” Brauer says. “And we have not been able to identify a safe level yet on air pollution.”
According to the WHO, air quality in most major cities around the world that monitor pollution fails to meet guidelines for safe levels. An updated urban-air-quality database shows that about half of the urban population being monitored is exposed to air-pollution levels at least 2.5 times higher than the WHO recommends.
The report also states that in most cities where there is enough data to compare the current situation with previous years, air pollution is getting worse, due to reliance on such things as coal-fired power plants and private vehicles, the inefficient use of energy in buildings, and the use of biomass for cooking and heating. All of that puts people at higher risk of developing serious, long-term health problems.
When it comes to cardiovascular disease, Reeves and Brauer reminds us that there’s no single risk factor. And just as people can mitigate their risk by not smoking and getting regular exercise, there are many measures they can take to improve air quality and their health as well.
Reeves shares those steps in Planet Heart, and the list is long, but here are a few: ride your bike, take public transit, or walk; if you drive and can afford it, consider a hybrid vehicle.
“Look at everything you’re doing to minimize your footprint and do whatever you can to have an impact on global footprint,” Reeves says, adding that eating the right food is essential to minimize risk.
“Do not buy industrial foods,” he says. “These have a lot of added sugar and salt and are linked with obesity and diabetes, which are factors in heart disease. We have everything to induce a perfect cardiovascular metabolic syndrome.
“The solution is very easy,” he adds. “Eat fresh as much as you can. Have [food] the way nature delivered it to us.”
Cities and governments must continue their efforts to be green too. Reeves suggests every city have at least a 20-percent tree canopy (to reduce both the levels and toxicity of pollutants).
If those organizations need any convincing, Brauer points to a financial argument: fewer health problems mean less strain on the public system.
“If you improve air quality, everybody benefits,” he says. “It’s really, really cost-effective.”