I reported yesterday that anti-smoking researchers have attacked the U.S. tobacco companies for failing to produce lower TSNA (tobacco-specific nitrosamine) cigarettes. The attack occurs in a research article published in the journal Tobacco Control. The attack on the cigarette companies is based on the research finding, reported in the article, that TSNA levels in current cigarettes produced by Philip Morris, Reynolds American, and Lorillard are not significantly lower than they were three decades ago. The researchers further assert that cigarettes with lower TSNA levels reduce cancer risk. Thus, they argue that the tobacco companies have been neglectful by failing to reduce the TSNA levels in their products.
Yesterday, I explained why the assertion by the researchers in this article is a fallacious one: there is no evidence that cigarettes with lower TSNA levels are safer than other cigarettes because there are more than 60 carcinogens in tobacco smoke and the processes by which TSNA levels are reduced (which represent only 2 of the 60+ carcinogens) might actually increase levels of other carcinogens.
Today, I explain why the assertion that "TSNA-light" cigarettes are safer than "full-TSNA" cigarettes is even more fallacious than the tobacco companies' historical assertion that light (low-tar) cigarettes are safer.
Reason #1: The researchers knew that there are more than 60 carcinogens in tobacco smoke, yet they were willing to draw a conclusion about cancer risk based on lowered levels of two of them, with no knowledge of the levels of the other 58+ carcinogens. In contrast, low-tar delivery at least is indicative of a lowering in levels of all constituents, across the board.
I am not in any way justifying the claim that low-tar cigarettes are safer than high-tar cigarettes. However, it is at least the case that low-tar yields are indicative, to at least some degree, of a lowering of many types of carcinogenic substances in tobacco smoke, across the board. Lower tar yields presumably (if they translated into actual lowering of human exposure) indicate a lower amount of carcinogens and toxins across the spectrum.
In contrast, reduced levels of TSNAs in cigarettes indicates a reduction of only two of more than 60 known carcinogens. Not only is there the problem of the machine yields not adequately representing human exposure, but even if the exposure estimate was accurate, it would indicate a lowering of exposure to only two carcinogens. With low-tar cigarettes, if the machine yields were accurate, they would at least be indicative of a more across-the-board reduction in carcinogen exposure.
In fact, there is some evidence that cigarette filters have conveyed a small degree of health protection by slightly lowering lung cancer risk because of substantial tar reduction, the benefits of which are not undermined (or not completely undermined) by smoker compensation.
For example, Armadans-Gil et al. reported a 60% reduction in lung cancer risk associated with long-term use of filter-tip versus non-filter cigarettes.
In addition, there is some evidence that very high tar cigarettes (greater than 21 mg) do confer an increased risk of lung cancer. For example, Harris et al. found a quite robust and consistent relationship between very high tar cigarettes and higher cancer risk compared to medium, low, and very low tar cigarettes. Presumably, these findings are explained by a modest degree of protection conferred by the cigarette filter -- an effect that is not completely undermined by smoker compensation.
Moreover, the researchers knew - or at least should have known - that the evidence presented in the Department of Justice lawsuit against the tobacco companies made it clear that lower nitrosamine cigarettes do indeed have a higher yield of other carcinogens. The primary process by which TSNA levels are reduced - substituting flue-cured tobacco for burley tobacco - has the adverse side effect of increasing levels of other hazardous smoke constituents, including carcinogens.
In fact, lower TSNA cigarettes were found in tobacco company laboratory experiments to produce higher tar yields, as well as to increase hydrogen cyanide, carbon monoxide, and aldehyde deliveries.
In her final decision in the DOJ tobacco lawsuit, Judge Kessler found as follows: "This process allowed substitution of air-cured Bright tobacco for burley tobacco, and thus represented a potential advance in reducing the delivery of harmful TSNAs to smokers. ... When the air-cured bright tobacco was substituted for burley tobacco in the control cigarettes, as described in the experiments discussed in the patent, there were instances in which carbon monoxide (“CO”), hydrogen cyanide (“HCN”), FTC tar, and aldehyde (“RCHO”), deliveries were increased."
In light of this evidence, it seems to me to be quite disingenuous to assert that a low TSNA cigarette is safer than, and less carcinogenic than other cigarettes, especially when you know that the tar delivery may well be higher.
Moreover, it seems hypocritical to attack cigarette companies for failing to lower the TSNA levels using these methods, since such an approach would probably have led to higher overall carcinogen delivery and the anti-smoking groups would then have made toast of the companies in the courtroom.
Thus, while the fallacy of the tobacco companies "lights" assertion is primarily that machine yields do not accurately reflect human exposure, there are two fallacies with the researchers' "TSNA lights" assertion. First is the machine yield fallacy. Second is the fallacy that lowering levels of two specific carcinogens will reduce cancer risk when the levels of many other carcinogens are likely being increased.
Reason #2: The government required cigarette companies to disclose machine-measured tar yields to consumers and therefore implied that low-tar cigarettes convey some degree of health protection.
Again, I'm not excusing the tobacco companies, but the government was complicit in the fraud perpetrated upon American consumers by requiring what they knew was fallacious health-related information. The "light" labels largely corresponded to government-mandated product testing and the companies were accurately conveying the results of that testing.
In contrast, the government is not in any way suggesting that lower TSNA cigarettes are safer and has - at least up until now - rejected the idea of requiring TSNA level reporting to consumers. In fact, the FDA clearly stated, just yesterday, that low-TSNA cigarettes are not any safer.
Thus, while the tobacco companies were making assertions that were in line with official government policy, the Tobacco Control article is making an assertion that directly contradicts the official policy of the leading federal agency that regulates tobacco products.
The Rest of the Story
I think it is important to close this commentary by repeating a set of important findings from the scientific literature. In their article on levels of tobacco-specific nitrosamines in different types of tobacco, Ding et al. concluded as follows:
1. "The pyrosynthesis of benzo[a]pyrene (BaP) in cigarettes made exclusively with flue-cured or sun-cured tobaccos produces higher BaP levels in the smoke than in cigarettes made with burley tobacco."
2. "In cigarette brands containing different types of tobacco that delivered low TSNA levels in smoke, PAH levels increased as TSNA levels decreased. ... King et al. further illustrated the inverse relation between BaP and NNK emissions (nicotine-adjusted) in Australian and Canadian cigarettes (16). Such findings are important because smokers concerned about their health risk may switch to a brand that delivers lower levels of a particularly worrisome chemical but may not actually reduce risk because of their overall exposure to other harmful chemicals."
Fortunately, one of the authors of this article was Dr. David Ashley, and so I don't think he is going to fall for the anti-smoking researchers' claim that lowering TSNA levels in cigarettes reduces carcinogenic risk and that the FDA should therefore require cigarette companies to lower the TSNA levels, as recommended in the Tobacco Control article.
The rest of the story is that there is an abundance of existing literature (I've only cited a few select articles) which indicates that the methods used to produce low-TSNA cigarettes result in products that have higher levels of other toxins and carcinogens, including polycyclic aromatic hydrocarbons, hydrogen cyanide, and benzo(a)pyrene.
So the truth is that the researchers who have blasted the cigarette companies for failing to reduce TSNA levels have also attacked the companies for keeping down the levels of polycyclic aromatic hydrocarbons, hydrogen cyanide, and benzo(a)pyrene.
In other words, the current thinking, research, and policy recommendations in tobacco control are really no more science-based than the original deception of consumers by the tobacco companies, for which those companies were found guilty of RICO statute violations.
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