The post I wrote yesterday encouraging stubborn smokers to take up smokeless tobacco as an equally self-harmful habit seems to be gaining supporters, at least scientifically. Cancer Epidemiology, Biomarkers, and Prevention (to which I have free access…hooray!) is reporting in their August issue both that a primary byproduct of nicotine known to cause lung and liver cancer, NNK, can be formed from secondhand smoke and that smokeless tobacoo contains more NNK and nicotine than regular cigarettes.

The former paper is especially alarming, as it reports experimental data compiled by Philip Morris as long as 25 years ago, in some cases, of which most was never reported or published. While the group that published this article had previously shown that secondhand smoke is fourfold more toxic than mainstream smoke (that is, the smoke to which a smoker is exposed), the primary findings of the present paper indicate that NNK formation increases rapidly in the local surroundings over a period of several hours after a cigarette is put out. That is, secondhand smoke clearly is harmful, and it becomes worse, and potentially more carcinogenic, even after that which is generating it is eliminated. This suggests that the dangers of smoking extend far beyond the localized duration of a single lit cigarette and the time it takes to smoke it—specifically, up to 11 hours’ worth of danger, according to Philip Morris themselves, over 20 years ago:

Over a period of 4 h a rapid increase in NNK concentration was observed and then a gradual decrease to almost 0 over the following 11 h. The decrease in NNK concentration was linked to the decrease in concentration of aerosol particular matter, rather than decomposition.”

Of course, most people smoke their cigarettes in the real world, not in airtight steel boxes with carefully balanced concentrations of airborne chemicals, so what happened when they repeated the experiments in an office setting where furniture, paint, and carpet could absorb some of the smoke? Same thing, albeit on a smaller scale. So, the next time you’re in a bar with a bunch of people around you smoking, remind yourself not only that, thankfully, you’re adsorbing much of the NNK that’s continuously forming in the air by merely breathing, thus reducing the amount of airborne NNK, but also that you’re adsorbing much of the NNK that’s continuously forming in the air by merely breathing. Lung and/or liver cancer, anyone? This point is not lost on the authors of this paper, as they plainly state right off the bat,

Exposure to secondhand smoke causes 53,000 of the 453,000 deaths caused each year by tobacco use in the United States. The ratio of mortality between active smokers and nonsmokers who are exposed to secondhand smoke (8:1) is remarkable because, in terms of the total mass inhaled, the dose for smokers is substantially higher than for nonsmokers.”

It couldn’t be stated more simply. Bystanders of smokers comprise 1/9 of the smoking deaths annually as a result of their exposure to secondhand smoke.

It is curious indeed that Philip Morris wouldn’t have published these incredibly informative findings but instead chose to leave them blanketed within mounds of files generated by code-named projects, isn’t it? Say it with me: “conflict of interest.” They close the results section with this powerful summary of their feelings toward Philip Morris:

Philip Morris did not publish their results on the formation of NNK in aging sidestream smoke. Philip Morris presented data from Project Poldi (on the general effects of aging on the chemistry of sidestream smoke) at the International Experimental Toxicology Symposium on Passive Smoking in Essen, Germany, in October 1986 but did not include data on tobacco-specific nitrosamines [such as NNK]. A manuscript listing tobacco-specific nitrosamine concentrations for the earliest time point, but not the increase in NNK concentration over time, was submitted to Beitrage Für Tabakforschung (a tobacco science journal) in 1988…No data from Project Tasso [another secretive project investigating the effects of cigarette smoke] seem to have been presented publicly.”

“Philip Morris did, however, present and publish work that emphasized the rapid loss of secondhand smoke components from room air by adsorption and ventilation. Publications in 1998 and 2005 from Philip Morris on the toxicity of experimentally aged sidestream cigarette smoke do provide tobacco-specific nitrosamine concentration data and show that NNK concentrations are elevated 10- to 20-fold relative to other tobacco-specific nitrosamines. However, unless the readers of these publications were aware that the concentration of NNK was only slightly higher than that of other tobacco-specific nitrosamines in fresh sidestream smoke, the fact that NNK forms as sidestream smoke ages will not be evident.”

The second paper compared the amounts of NNK and nicotine found in cigarettes and smokeless tobacco by detecting NNAL and cotinine levels, approximations for exposures to NNK and nicotine, respectively, in subjects who engaged in each habit independently of the other. (Because these markers were detected in urine samples, they were normalized to creatinine levels to “equal the playing field” across all subjects.) This, briefly, is a summary of what they found (click for full-size image):

So, to smokers, I will say it again: You can do better than mere cigarettes! Need some cancer? Go for the smokeless stuff. It’s a win-win situation for smokers and non-smokers alike. In the end, you can have your nicotine and eat it too!

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Sources:
Schick SF, Glantz S. Concentrations of the carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in sidestream cigarette smoke increase after release into indoor air: results from unpublished tobacco industry research. Cancer Epidemiol Biomarkers Prev. 2007;16:1547-53. doi:10.1158/1055-9965.EPI-07-0210

Hecht SS et al. Similar exposure to a tobacco-specific carcinogen in smokeless tobacco users and cigarette smokers. Cancer Epidemiol Biomarkers Prev. 2007;16:1567-72. doi:10.1158/1055-9965.EPI-07-0227

Schick S, Glantz S. Philip Morris toxicological experiments with fresh sidestream smoke: more toxic than mainstream smoke. Tobacco Control. 2005;14:396-404. doi:10.1136/tc.2005.011288