Does Smoking Increase Heart Disease? If So, Why?

Mr. Heisenbug says that smoking is the best predictor of heart disease. (Not quite. A high Agatston score is a better predictor. For example.) It is the best lifestyle predictor. People who smoke, according to this, have a six-fold increased risk of heart disease compared to non-smokers.

Why would this be? Heisenbug points to a study that found that when smokers quit, the microbial diversity of their gut increased. He speculates that (a) smoking decreases microbial diversity, which is quite plausible and (b) decreased microbial diversity increases heart disease — which has some plausibility.

I commented:

It would be interesting to find other factors that have a big effect on microbial diversity and whether they are also associated with heart disease. The idea that smoking causes heart disease via its microbial effects predicts, or at least suggests, that a change that reduces microbial diversity a lot will increase heart disease.

Heisenbug replied:

The only lifestyle factor that we can safely say leads to a lack of microbial diversity is a diet that is low in fermentable fiber. And fiber intake is consistently linked (negatively) with heart disease. I’ve never seen data linking lower overall diversity to a decrease in risk for any disease. And lots showing the opposite.

I replied:

The stuff about diversity (fiber intake increases diversity and is associated with less heart disease, many associations of more diversity with less risk of Disease X, no associations in the opposite direction) is substantial support for your idea, in my opinion.

His theory, in other words, made a prediction that turned out to be correct. A large fraction of what we’re told about health hasn’t led to any correct predictions. Here is an idea about how to prevent heart disease, a major killer, that there is actually reason to believe. And Heisenbug can say whatever he wants, in contrast to a heart disease expert quoted, say, in the New York Times, who is under pressure to say certain things. So we can take what he says at face value.

Heisenbug replied:

I agree. Especially because there’s never been a good explanation WHY fiber has that effect on [he means "association with" -- Seth] heart disease.

Suddenly I am a lot more interested in microbial diversity and the association of fiber and heart disease. Smoking has countless health effects — it increases many cancers, for example. Obviously it increases lung and throat cancer. This means there are many ways it could cause heart disease. Fiber is quite different than smoking and as far as I know has no effect on lung and throat cancer. If it could be established that fiber causes a reduction in heart disease (not just is associated with a reduction), that would be considerable evidence (but far from proof, of course) that microbial diversity influences heart disease.

14 Responses to “Does Smoking Increase Heart Disease? If So, Why?”

  1. Andy Says:

    I think this is nonsense.

    Quitting smoking is associated with an increase in phylum firmicutes bacteria(often associated with, obesity heart disease and T2D). Smoking is associated with an increase in bacteroides recently famous because they promote leanness.

    Trying to dig up a study where smoking was associated with increased bacterial diversity in UC patients especially in byutrate producing groups and nicotine patches reduced occurrence of flare ups.

    I’d say it’s a fair bet the increased heart rate and blood pressure inflict most of the damage.

  2. Nancy Lebovitz Says:

    I’m not going to say it’s the strongest factor, but sunlight seems to do a lot to prevent heart attacks by a path which doesn’t involve vitamin D. Exposure to sunlight causes human skin to release a precursor for nitric oxide.

  3. dearieme Says:

    “Coronary Calcium Independently Predicts Incident Premature Coronary Heart Disease Over Measured Cardiovascular Risk Factors”: now there’s a fine sample of lousy English.

  4. Charlie Currie Says:

    Andy says: “Smoking is associated with an increase in bacteroides recently famous because they promote leanness. ” So what’s going on with all the obese smokers?

    Also: “I’d say it’s a fair bet the increased heart rate and blood pressure inflict most of the damage.” From this – “http://www.ncbi.nlm.nih.gov/pubmed/9162447″ you get this – “It is a paradox that while smoking acutely increases blood pressure, a slightly lower blood pressure level has been found among smokers than nonsmokers in larger epidemiological studies.”

    Exercise also acutely increases heart rate and blood pressure and regular exercisers are known to have lower heart rates and blood pressure than non-exercisers, yet exercise is recommended as a defense against heart disease. Go figure.

  5. Nancy Lebovitz Says:

    Just for another angle– Wim Hof (who does a lot with enduring cold) believes that intermittent exposure to cold (like cold showers) increases the flexibility of blood vessels.

    It could make sense that exercise + rest is good for the circulatory system because it increases its range in a way that constant high blood pressure doesn’t.

  6. Heisenbug Says:

    Thanks, Seth, for leading me to that initial insight. I put it in my back pocket, and forgot it was there.

    I do think there must be protective factors when it comes to smoking. And not just for heart disease. But there just isn’t much fiber/cancer research out there, probably because it isn’t intuitive the way it is with heart disease. Colorectal cancer being the only exception, for obvious reasons. No one cares about the microbial link, so the disease has to have a clear & intuitive dietary connection to merit fiber research. But there is some data to at least raise suspicion:

    http://www.ncbi.nlm.nih.gov/pubmed/1851150

    “Of the seven case-control studies, which evaluated the relationship between the fiber-rich diet and breast cancer, six demonstrated an inverse association. For cancers of the esophagus, mouth, pharynx, stomach, rectum, endometrium, and ovary, there are only a limited number of studies, most showing a protective effect from eating a diet high in fiber-containing foods.”

    But we can always start from the other end — the microbiome/cancer link. A decent amount there:

    http://www.nature.com/nrc/journal/v13/n11/abs/nrc3610.html

    And since we know fermentable fiber is a (if not THE) major modulator of the microbiome, I think there’s enough for a similar inquiry.

  7. Heisenbug Says:

    Andy,

    The research you are referring to is outdated.

    In fact, if you read the blog posts where I talk about this, you will see that the research indicates the opposite of what you say, and figures prominently in the case that’s being made.

    I’d be interested to see whatever UC study you are referring to. IBD and microbiota is pretty complicated, but most of what I’ve seen involves a reduction in the butyrate-producing Clostridia (ie, Firmicutes), which is a big part of the microbial pattern I’ve documented.

  8. Antonio Says:

    Interesting but it seems to be one of those guesses that makes very sense outside the country. In Europe it seems that a lot of people smoke but the incidense of heart disease is lower than USA. This seems to be specially true in France.

  9. Heisenbug Says:

    Andy,

    I forgot to address the last part of your comment.

    “I’d say it’s a fair bet the increased heart rate and blood pressure inflict most of the damage.”

    You don’t mention how, or what mechanism, but I’ll assume you are referring to nicotine inducing those affects.

    Pipe-smoking exposes smokers to far less nicotine, yet has not been found to be any safer:

    http://www.ncbi.nlm.nih.gov/pubmed/20952559

    Nicotine patches do not contribute to arrhythmia or ischemia:

    http://www.ncbi.nlm.nih.gov/pubmed/9784902

  10. JM Says:

    So if smoking is the best lifestyle predictor, what could we learn if we looked at the people who smoke for years and never get heart disease – what is it about them that protects the heart? The first example that I can think of is a family friend who recently died, in his 90s and active but also still smoking. And he is not the only one I have known. A more thorough analysis of these smokers, including things like their gut health, might actually yield some good answers. But since all most experts want to focus on is cholesterol!

  11. William Blair Says:

    Forgive my ignorance – is it the smoking that causes this particular problem mentioned (not including the obvious hazards – you’re inhaling smoke!) or is it the nicotine that causes the microbial diversity?

  12. William Blair Says:

    *that causes the reduction in microbial diversity*

  13. Heisenbug Says:

    William,

    It’s a good question. Unfortunately, the study did not look into that, so we do not know. But as I mention in the original post, tobacco smoke has been shown to directly introduce pathogenic bacteria & their endotoxins into smokers. So that would suggest it is not, in fact, the nicotine.

  14. William Blair Says:

    If I could, I would have a study conducted with smokers of all “flavors” – cloves, pot, tobacco (those seem to be the most popular / quasi-legal ones) and see what happens. My guess is that smoke is the culprit. I think having all varieties of “common” smoke in the study would would lead to a more definitive conclusion.

    Thanks, Heisenbug.