Tuesday, October 18, 2005

The Risk Associated With Secondhand Smoke

by Tom Bozzo

A commenter to the post on the Madison indoor smoking ban and the would-be recall of Mayor Dave Cieslewicz claimed that the research into the health risks of secondhand smoke is too inconclusive, and the estimated risks too small besides, to warrant the remedy of the ban. I'm not a public health researcher, but thanks to the miracle of the internets, I nevertheless was pointed to one of the seminal papers on the topic, this 1993 JAMA article that estimated a 50% increase in lung cancer risk for food-service workers at establishments permitting smoking. Need I add that the author of the article, Mike Siegel, has a blog, too?

The synthesis of subsequent research I gather from Siegel's blogging is that the health risks are sufficient to justify the remedy of banning indoor smoking in all public places, whereas outdoor smoking bans (which have been pursued elsewhere) can't be justified by health concerns.

I suppose it is possible to argue that, notwithstanding the substantial increase in risk, the risk level remains low. The catch is that there doesn't seem to be any reason to believe that workers are compensated for accepting the risk — and, further, such clear but not present dangers aren't things people are obviously good at weighing rationally.
A 50% increase is practically immeasurable. These studies are all statistics, and anything less than a 100% increase in something is a very weak association - here second-hand smoke is weakly associated with lung cancer.

I'm not saying all smoking studies are bad, or that there are no health problems associated with smoking, but statistics don't really provide a lot of useful info in this case. Many studies have found no association between second-hand smoke and lung cancer. I know people are good about only citing the ones that find a link, though.

As far as being compensated for risk, any number of factors could affect someone's health. People who work in smoke-free office cubicles might have larger health-risks because they sit down all day and don't get to look outside. It's all statistics, and it's all most likely crap.
Bryan, a really good way to lose all credibility with a practicing econometrician is to write something like, "It's all statistics, and it's all most likely crap."
i didn't mean all statistics are crap, just that studies that try to associate something like a disease or a health benefit with one particular item (or over someone's lifetime of consuming that item in addition to several trillion other things) are most likely crap. I think you would certainly know the difficulties is analyzing data sets like this where so little data is available and all the data is influenced by a variety of unknown variables. But, you're the expert, so you can tell me.

Red wine is good for you, until it's found to be bad, then good for you again. Coffee is bad for you, but then again it is good for you. I'm guessing that one of these days, nicotine will be shown to be significantly beneficial to health.
Bryan: You're not off the hook. There are, no doubt, good and bad statistical studies in the health literature.

As I said, I'm not a public health researcher, but this would seem to be a case where epidemiological methods are a propos. Trying to predict which otherwise non-smoking tavern denizens will specifically be harmed is practically impossible, but some will be (and badly so). That has to be weighted against the absence of a real net benefit, beyond exercising the "right" to pollute someone else's air, to the smokers who cause the harm.

Also in this case, we're talking a link between a known carcinogen and a cancer that has tobacco use as a major cause. That's not exactly the sort of far-out connection that requires extraordinary evidence to be believable.

Not that I wouldn't like your Sleeper theory to be true (I am a reformed smoker, BTW), but I'd also like a pony, thanks.
Them's fighting words, Bryan.

If secondhand smoke was really weakly associated with risks, then why did the tobacco industry settle a lawsuit brought by flight attendants who claimed to have suffered harm from it? As far as I know, it's the only lawsuit brought by private citizens that the industry has settled. I know $300 million is a drop in the bucket to the tobacco industry, but the fact that they thought it would be cheaper to settle the class-action suit and make the plaintiffs bring their claims on an individual basis suggests to me that the industry itself knows that the evidence for harm on a population level is unassailable.
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