Bernie Greene wonders just how scientific is the science behind the smoking debate over on Samizdata.
I shall have to assemble a category on smoking – I like the last comment the best. He pretty much blows Bernie out of the water – and at least Bernie did ask for a more educated opinion.
As an epidemiologist, I hardly know where to begin with this post. I encourage the author to read an introductory book on epidemiology before dismissing the field; I suggest Epidemiology in Medicine by Charles Hennekens. If he did read it he might not be a skeptic about smoking and lung cancer. To wit- there are several criteria that denote causality. Among them are temporality (exposure preceded disease), dose-response (more exposure = more disease), strength of effect (bigger numbers means that biases are less likely to have produced them) and biological plausibility (lung exposed to floating carcinogens… hmmmmm). Smoking fulfills all of these criteria.
The author also appears not to know that causes come in different types. They may be necessary but not sufficient to cause disease. In this type of causation it is not surprising that only a fraction of exposed people develop disease.
To read the author you would think that all research on lung cancer stopped in the 50’s, when in fact plenty of research continues to this day that explains, among other things, genetic susceptibility to developing lung cancer among smokers. For instance, N-acetyltransferase is an enzyme that clears tobacco carcinogens from the body. People with the slow-acting form (slow acetylators) are at a higher risk for lung cancer than people with the fast-acting form (fast acetylators). So it’s not as if there is no curiosity on the part of scientists to find out what else, besides smoking, affects risk of lung cancer. There’s an enormous literature on the subject if anyone cares to look on Medline. Incidentally, I would like to imagine the author coming up with a concise way to tell the public that it’s alright to smoke if they have the correct genetic polymorphisms for thirty different susceptibility genes.
Lastly, the author criticised unnamed scientists for demanding something be done about tobacco. I truly doubt the author did anything like go back to the historical record to determine who advocated what law and when. Nevertheless, I’d agree that most of my fellow scientists instinctively fall back on statist solutions to modify disease risk. But let’s be clear- that does not invalidate the science. I’m sure the author can recognize an ad hominem argument when he sees one.
Finally, here is a brief list of eliminable exposures and the diseases they caused as described by the dread Epidemiology:
sleeping baby on the stomach – SIDS Hepatitis C – hepatocellular carcinoma diesterstilberol – vaginal cancer Rely tampons – toxic shock syndrome L-tryptophan – eosinophilia myalgia sydrome HIV – AIDS
On behalf of my field, I accept your thanks.