Science Lesson: Even If Smoking Were New, We Would Already Know It Is Harmful
Last week’s science lesson explained how we know that vaping poses little or no health risk, despite the claims that we just do not know enough. One of the favorite tropes offered in support of the latter claim is that it took decades to realize smoking is so harmful, and therefore we cannot know anything about vaping until decades have passed. This is wrong both because we have a good measure of vaping, as previously explained, and because today we would already know smoking is harmful if it had only come to exist in the past few years.
The suggestion that we would need to repeat the development of health science methods and knowledge in order to learn something today is simply silly. By that logic, when a new infectious disease appears, we need to go through millennia of believing it is caused by evil spirits, imbalanced humors and miasma, before reinventing germ theory for the particular disease and looking for a cure. That is not how history and technology work.
If smoking tobacco were a new innovation (obviously a far-fetched counterfactual), health science experts would immediately be concerned about it. The smoke is effectively the same as that from indoor use of solid fuel, particularly primitive cookstoves, which we know create a high risk of disease. It is fairly similar to severe outdoor air pollution, with its known harms. Instead of saying that breathing in New Delhi is like smoking two packs a day, we would instead say that the new practice of smoking is probably as harmful as breathing in New Delhi.
We would also quickly accumulate useful laboratory data. Consider those studies that compare the effects of vapor and smoke on in vitro cells or living tissue. We focus on the lack of measurable effects from the vapor, paying little attention to the expected harmful effects from the smoke. But if the latter were new information, it would be an immediate warning that the exposure appears to be quite harmful. Short-run clinical studies would show the rapid reduction in respiratory functioning and harmful blood carbon monoxide levels in smokers.
None of this would be sufficient to estimate exactly how risky smoking is. We could try to estimate the total magnitude by extrapolating the measured effects of indoor cooking, outdoor air pollution and various occupational exposures. This could easily be wrong by an order of magnitude in either direction. However, that would tell us smoking poses a huge risk, among the greatest among any consumer choice or common involuntary exposure.
If we wanted to make precise estimates of risks, we would indeed need to wait until we had epidemiology. Biology is complicated, so estimating risks based on extrapolations, chemistry and toxicology is often very inaccurate. For example, if we extrapolated from current estimates about the effects of air pollution, we would conclude that smoking is actually quite a bit more harmful than it really is.
By the same token, if studies of vapor chemistry had suggested it was substantially hazardous, there would be no way we could conclude that it was 5 percent as hazardous as smoking, rather than 1 percent or 25 percent. But since the results show that is approximately harmless, we can be fairly confident in our conclusions.
Thus, if smoking were new, available science would not tell us whether it was more or less hazardous than, say, extreme obesity, but it would tell us it is up there. As soon as the new smoking fad was recognized, the message would go out: Unlike dipping and chewing tobacco, or using extracted nicotine products – which only a few puritanical kooks claim are harmful – smoking appears to be extremely dangerous. Avoid it and stick to safe ways of using tobacco.
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