Thursday, May 09, 2013

A Positive Health Effect From Smoking

I just came across an interesting article reporting on new evidence suggesting that eating peppers substantially reduces the risk of getting Parkinson's disease. It mentioned, in passing, that it is well established that smoking anti-correlates with getting Parkinson's.
The observation that smokers have a lower risk for PD has been "consistently reported in more than 60 epidemiological studies," Honglei Chen, MD, PhD, from the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, who wasn't involved in the study, told Medscape Medical News.
 The link between smoking and peppers is that both tobacco and vegetable peppers are in the same vegetable family (Solanaceae) and that pepper contain small amounts of nicotine.

The information about peppers is more relevant to me than the information about smoking, since smoking has enough negative effects to make it quite unlikely I will start doing it—although I have played with the idea of trying one of the smoking substitutes, such as a nicotine patch or an eCigarette, to see if I like the effects. But the information about smoking is more interesting, precisely because the fact that I was not aware of it is evidence of a problem with the mechanisms by which information reaching me gets filtered.

Assuming that the quote from Chen correctly reports the evidence—a quick google suggests it does, and that the effect is substantial—it is surely relevant to the question of whether people ought to smoke, a positive effect, possibly a substantial one, to set against the well established negative health effects. So why has it not been widely reported, at least widely enough so that I would have heard of it? Why does it only appear as a passing comment in a news story about something else?

My guess is that it is for the same reason that the evidence that moderate alcohol consumption is good for you is not widely known, a point I discussed here about a year ago. It is widely, and I think correctly, believed that smoking is bad for you. Hence publicizing evidence against that belief, evidence that in at least one important respect smoking is good for you, amounts to supporting the bad guys, which very few people, whether scientists or journalists, want to do. The result is a sort of informal and unofficial censorship, a filtering of the information that reaches the public to make the case for whatever the conventional view is look stronger than it is.

In a previous post I expressed my skepticism about popular claims on the magnitude of the negative effect of second hand smoke. While I think those claims are bogus, my guess is that second hand smoke does have negative effects, since there is good evidence that smoking does. But ...

For a long time, opponents of nuclear testing argued that the resulting increase in background radiation increased the rate of cancer and birth defects, on the grounds that high levels of radiation were known to do so. The implicit assumption was that the negative effect was proportional to the dosage, that if a large amount of radiation had a substantial effect, a small amount had a proportionally smaller effect. As I understand the evidence, that assumption turned out not to be true, the standard counterexample being Denver. Because it is about a mile above sea level, the background level of cosmic radiation is higher than most other places people live, but rates of cancer and birth defects are not correspondingly elevated, indeed may not be elevated at all. 

That suggests that human biology can deal with low levels of radiation,  has problems only with high levels. Suppose that turns out to be true of the effect of tobacco smoke as well. From the same article:
"A few studies suggest that secondhand smoke might be associated with a reduced risk of PD, so that prompted us to look at another source of a relatively small amount of nicotine — foods in the same plant family as tobacco," [Dr. Searles Nielsen] added.
If it turns out that secondhand smoke does reduce the risk of Parkinson's and does not cause cancer, heart attacks, or other adverse effects associated with smoking, secondhand smoke might, aside from the unpleasant smell, be good for you. If so, even if the evidence turns out to be reasonably good, it may be a long time before you find out.


DR said...

I've mentioned on here before that I believe that nicotine on net has positive health benefits for most people. Almost all the negative health problems of smoking are due to the combustion of the cigarette, not the nicotine therein.

Nicotine undisputedly has positive neurological health benefits. It very likely has at least minor effects on arterial stiffening. The question of nicotine's health largely comes down to whether the former outweighs the latter.

I would say that people with a family history of Alzheimer's or neurological disease, without much history of heart disease, should probably supplement an e-cigarette or nicotine gum at least once a week.

RKN said...

What DR said.

Moreover, mammals have nicotinic receptors on neurons which function to control, in part, activities in the central and peripheral nervous system. Perhaps not surprising, agonizing those receptors may be PD protective.

But I don't think the evidence of the health dangers of smoking cigarettes is made to "look stronger than it is," merely by not reporting that a single chemical component in cigarette smoke is possibly protective against certain human diseases.

Specific chemical components found in poisonous snake and spider toxins have certain health benefits in humans too, but...

You make a curious point about about SHS, should it turn out to be benign and potentially PD protective, but for my taste I'll stick to exposing myself to wine.

Power Child said...

I think this is spot on, though I'd say the positive health effects of moderate alcohol consumption are fairly well-known by this point. I've seen references to it on TV shows like "The Office" for example.

Rebecca Friedman said...

I mentioned the positive effects of moderate alcohol consumption in my Italian literature class a couple weeks ago (during the break, while chatting) - both people I was talking to seemed to take it as standard, accepted fact. And I think I've seen it in Italian/French beginning language books. Then again - people studying languages of countries where moderate alcohol consumption is the standard may be more likely to know that particular fact.

affenkopf said...

Here in Germany I don't think a month goes by without an "a beer/wine/whiskey a day is good for you" article in the popular press.
Is this really that different in the US?

Regarding Rebecca Friedman's point:
I wonder if the reporting of positive health effects of smoking is more prevalent in the press of countries with high rates of smoking like China.

Tibor said...

affenkopf: Well, the Czech republic is 12th in the world in cigarette smoking per capita and I have never seen any article pointing out anything like this. However, the current health minister is trying to ban smoking in pubs completely and require state licence from anyone who sells cigarettes. They even tried to ban electronic cigarette smoking in pubs, but that met such opposition that they changed the proposal just to regular ones.

I don't think consumption is closely related to the media bias. At least not in our country.

But there are a lot of articles about "one wine a day keeps the doctor away" and similar ones about beer.

It seems to me that tobacoo is subject to similar "fashion trends" as global warming. It is "progressive" to be against it, so a lot of people are trying to show how "enlightened" they are. Now, I'm not a smoker and I am pretty sure tha from the health perspective it has net negative effects, but the atmosphere in most media is such that smokers are almost "untermenschen".

Anonymous said...

I think part of the problem is that humans are really terrible at judging relative risks. Humans seem to have only a couple of risk categories: not risky, a little risky, and really risky.

That is why we accept groping before getting on planes.

Consequently, giving humans too much data about risk is not effective because we aren't all that good at processing it.

Todd said...

The phenomeon you describe -- beneficial effects of low dose toxins or stressors, such as nicotine, alcohol and radiation -- can be generalized. The scientific term for this is hormesis. Calabrese, Rattan and others have documented hormesis for a wide range of chemicals and stressors, across the animal and plant kingdom. Hormesis works by activating a number of key defense and repair mechanisms that enhance the resilience of organisms.

I have a blog, "Getting Stronger", that is devoted to applications of hormesis to improving health, using practices such as intermittent fasting, intense exercise, and cold showers:

CC said...

Bryan Caplan poked a hole in the whole "moderate alcohol is good for you" idea here.

pobody said...

Re: positive effects of nicotine

Bernhard said...

As far as I'm aware evidence for the beneficial effects of moderate consumption of alcohol are only epidemiological.
Healthy people of the workforce tend to drink small amounts of alcohol. Sick and old people tend to not drink alcohol at all. And alcoholics drink lots obviously. So this kind of studies likely only shows that healthy people have a longer life expecancy than sick, old and alcohol dependend people.

Unknown said...

I am happy to know that smoking my favorite Davidoff cigarettes reduces risks for development of Parkinson disease! It is one uncurable disease... Yeah, it is very good that smoking has positive effects too.

Patri Friedman said...

A crucial fact about the health effects of "smoking" is that the benefits are all benefits of nicotine, and most of the harms are harms of smoking and or tobacco. There are a few exceptions (high blood pressure and other effects of vasoconstriction), but the big stuff (cancer, emphysema, COPD, etc) is all from inhaling burning material or other chemicals in tobacco.

So the cost/benefit profile for pure nicotine in other forms - patch, gum, lozenges, e-cigarettes, etc - is totally different. I used e-cigarettes for a year or so, found them quite enjoyable, but unfortunately my lungs are sensitive enough that even e-cigarettes bothered them.

Nicotine is preventative against Alzheimer's, too, for related reasons to PD, I think.

And ditto on what Todd said about hormesis, although it requires some caution - don't activate stress responses when your overall stress load is high.

David Friedman said...

According to something I came across when looking for information on this, there is some evidence that caffeine is also protective. It looks as though there is less evidence due to less data, but the size of the estimated effect is similar.

And, on my rough calculation, my level of consumption of diet cola gets me enough for about a .5 reduction in probability.

Unknown said...

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