A doctor trying to lower a patient’s risk of heart disease, which is the single most common cause of death in the United States, would advise him or her to quit smoking, eat more vegetables and fruits, increase physical activity, and manage stress.
But there’s a significant risk factor doctors rarely mention. Living near a major roadway can increase one’s chance of heart disease by 38 percent, depending on gender and the type of disease. Even short-term exposure increases risk.
The evidence that air pollution impairs heart health was strong enough a decade ago that the American Heart Association (AHA) issued a science statement. A study published last month estimated that the risk is substantially higher than the studies cited in that statement. The jaw-dropping 38 percent figure applies to sudden cardiac death among the female nurses in a longitudinal study. Overall, the chance of death from heart trouble was 24 percent higher among nurses who lived very close to a road.
Living Near a Roadway Is a Risk Factor
“On a population level, living near a major roadway was as important a risk factor as smoking, diet, or obesity,” the study’s author, Jaime Hart, Sc.D., an instructor in medicine at Brigham and Women’s Hospital and Harvard Medical School, said in a press statement.
But doctors still emphasize the more established risk factors when they talk to patients, according to Dr. Richard Josephson, the director of cardiac intensive care at Harrington Heart and Vascular Institute in Cleveland and a member of the American College of Cardiology’s Prevention of Cardiovascular Disease Committee.
“If I had a choice would I choose to live above the Lincoln Tunnel or the Holland Tunnel in New York City? No, probably not, but by the same token I wouldn’t eat a cheese omelet for breakfast,” Josephson said.
Further Studies Needed
In part doctors don’t feel the science is settled enough to present to patients. The research on roads and heart health comes from observational studies, which don’t nail down a specific cause, and the studies identify widely ranging estimates of the risks.
“In order to make these recommendations, we need to have evidence. In the meantime, people should exercise, eat healthy, not smoke, not gain weight, and that will help them be healthy,” said Dr. Martha Daviglus, director of the Institute for Minority Health Research at the University of Illinois at Chicago and a spokeswoman for the American Heart Association.
The strongest research suggests that air pollution, specifically fine particulate matter, stresses the cardiovascular system. The tiny particles, whose sources include cars and trucks, can be inhaled and absorbed in the bloodstream, causing inflammation.
Reducing Air Pollution Is Key
If doctors knew what to tell patients to do about the risks of living by a road, they’d be more likely to raise the issue with them.
“If you said, ‘Studies show that blah blah,’ what are people going to do? Are they going to say, ‘Okay, then, we are going to move?’” said Daviglus. Those who live by major roadways are disproportionately poor, she noted.
The AHA had some debate about whether to make a statement about air pollution, because they knew it would likely cause anxiety without offering patients any remedies, Daviglus said.
Still, 96 percent of those who die of cardiovascular problems have at least one of the widely accepted risk factors, Daviglus said. Most of us have room to improve our diet and physical fitness, so it may make sense for doctors to gloss over the air pollution data when they talk to patients.
“It would be crazy for someone to move to an apartment a half mile away from the road but sit around all day eating bacon cheeseburgers and smoking cigarettes and think that they’ve made a positive lifestyle choice,” Josephson said.
But if it’s not clear what individual patients who are exposed to traffic can do to protect their hearts, it’s all too clear what policymakers need to do: reduce air pollution.
“From a social point of view, it would be better to minimize pollution at its source than having the individuals who have the wherewithal to move, move, and having a game of musical chairs where the vulnerable are left near the roadway,” Josephson said.
The AHA is just beginning to include clean air in its lobbying efforts. Its 2014 to 2017 policy agenda includes some standard approaches to cleaning up our roadways: stricter standards for tailpipe emissions, improved fuel efficiency, support for non-gasoline fuels and carpooling lanes and enforcement of anti-idling laws. (In many places, it’s illegal to run the engine in a parked car for more than a few minutes.)
And they’re also starting to encourage doctors to educate patients about air pollution.