Smoke inhalation: Cardiovascular risk factor

The recent Canadian wildfires that have caused a thick blanket of smoke to cover the upper Midwest and Northeast is, as reported by the media, a threat to people with lung conditions. But it also adds to risk for heart disease, rarely or never mentioned and therefore often dismissed. 

But smoke inhalation is indeed a cardiovascular risk factor. Here is some of the most compelling evidence for this phenomenon.

Transcript

Wildfire Smoke And Hidden Heart Risk

William Davis, MD 0:00

I'd like to talk about smoke inhalation as a cardiovascular risk factor. If you've been watching the news or if you just went outside, if you live in the upper Midwest or the northeast coast of the U.S., you know that there's been this pouring in of smoke from the wildfires in Canada, extensive, huge wildfires through a lot of Canada, especially in Ontario, it's coming down to the U.S. And so the media has done a good job by reporting to people to stay clear of this air until it clears up because it causes problems in people with lung conditions, asthma, chronic obstructive lung disease, and other lung conditions. But one thing I've not heard mentioned is the fact that smoke exposure is also a cardiovascular risk factor.

The Evidence Beyond Lung Problems

William Davis, MD 0:47

We know this from several lines of evidence. So we know, for instance, that people who are exposed repeatedly, such as in California and the nearby states, to the smoke from repeated prolonged wildfires do have an increase in cardiovascular events. Cigarette smoking, of course, is a well-established risk factor for cardiovascular disease and heart attack. Now, cigarette smoking, of course, not one thing. It's not burning wood smoke, right? It's got other things, heavy metals and other toxic compounds,

Firefighters And Early Coronary Disease

William Davis, MD 1:15

but nonetheless, in there is smoke inhalation as one of the components that causes lung disease and heart disease. We know that people who are exposed to air pollution, now air pollution, not just smoke, of course, it's many different things, including car exhaust and particulate matter, heavy metals, and many other things. So it's not as clean as just smoke from burning wood. But nonetheless, people who live in more polluted urban centers do have a several fold higher risk for cardiovascular events and cardiovascular death, unfortunately. We know that firefighters who are exposed, of course, to fi to smoke frequently, also have premature coronary disease. You know, years ago when I set up a heart scan center in Milwaukee, Wisconsin, the first center in all of Wisconsin, one of the first centers in the entire Midwest, and we started scanning people. But one of the things we did, because it was known even back then, so 30-some years ago, we knew that firefighters were developing coronary disease before other people did. And so we offered free heart scans to firefighters, and indeed we did see men who are showing, mostly men, showing higher caronary calcium scores, men in their 30s, 40s, and 50s. And of course, that programs you for earlier events like heart attack. And in fact, about half the deaths that occur on the job in firefighters are from sudden cardiac death, the other half from smoke inhalation or fire. So sudden cardiac death, carneartic is a real issue in these firefighters, unfortunately, who put their lives on the line but are exposed to smoke and other dangers.

Mummies Reveal Smoke Driven Atherosclerosis

William Davis, MD 2:50

And there's also an unusual source of uh proof that smoke inhalation is a carneary risk factor, in that there was a study called the Horace Study, in which the mummified remains of about 300 people, long dead, many thousands of years, were studied by CAT scan. They were looking for evidence for aortic and coronary atherosclerosis mostly. And it became clear, by the way, the majority of mummies were from Egypt, and that's kind of a skewed population, right? Because those are mostly royalty or elite. And there was some aortic atherosclerosis, some carotid, and others, and very little coronary, 0.4% of those mummies showed coronary disease. So they did have atherosclerosis, but tend not to have it become a problem, certainly not coronary atherosclerosis. But buried in that study and not made talked much about were the handful of hunter-gatherers that were studied. So that the horror study evidence and several other pieces of evidence in which hunter-gatherer populations were studied, have shown that they are virtually free of coronary disease, heart disease, even if they live to longer, later years, like 60s and 70s. So coronary disease is for all practical purposes non-existent in hunter-gatherers, with one exception. That was the handful of people from the Anongan population. These are people who lived in the islands, the Aleutian Islands in the Bering Strait between Siberia and Alaska. So an Arctic environment. These people living in an extremely harsh environment had homes that were partially buried beneath the soil to maintain warmth, and they would burn whale and seal oil for both light and for warmth, and they did not do a good job of venting the smoke from burning those oils, such that their mummies showed blackened lungs from smoke inhalation. So these were the rare hunter-gatherers, the exceptions to the rule that a hunting-gatherer lifestyle spares you from coronary disease. So they had two of the mummies out of uh four or five, I believe, had extensive coronary disease, including a woman in her 40s. So it's the exception that were exposed to smoke because of the poor venting. Now, interestingly, of course, they also had a very high intake of omega-3 fatty acids because of their diet based largely on seafood as well as whales and walrus and seal. And so they still had coronary disease. So it's an example of the power of smoke over a prolonged period, of course, to cause coronary

How To Reduce Smoke Exposure

William Davis, MD 5:29

disease. And I point this out because, one, the media has not been talking about that, and two, I think it's caused people to become kind of complacent, thinking if they don't have asthma or lung disease, that it's okay to get exposed to this smoky air. And it's not, of course. Now, a few hours exposure is not sufficient to cause coronary disease, of course. But you know, as wildfires and pollution have become more and more of a problem in many modern societies, I do get concerned that people are kind of brushing aside this aspect of smoke inhalation as a cardiovascular. So as long as the air quality remains poor, you really have to stay indoors, filter your air, whether it's in your home or in your car, and you do want to minimize your exposure to smoke, both for lung reasons, but also for cardiovascular reasons.