Smoking and Tobacco Control Monograph No. 7 
cigarettes, but the differences are small and not quantitatively proportional 
to nominal yield. Tar and nicotine ratings are poor predictors of human 
intake, except for those cigarettes that happen to be rated by smoking 
machines as 1 mg nicotine per cigarette, in which case that rating 
fortuitously fits the population average. Tobacco manufacturers have 
stated that the FTC method was never intended to measure intake in any 
individual. The author agrees. However, data for 2,000 people summarized 
here indicate that the FTC method does not work for the general population 
of smokers either. 
In general, the FTC method underestimates human exposure. Smoking- 
machine-derived tar-to-nicotine ratios, which have been used to argue the 
benefit of switching to low-yield cigarettes, are not of value because these 
ratios change with changes in smoking behavior. On the other hand, 
because there is some relationship between yields and nicotine, and although 
the slope of that relationship is shallow, it is not recommended that smokers 
regress to smoking higher yield cigarettes. 
QUESTION-AND-ANSWER SESSION 
DR. RICKERT: When we first looked at this back in 1981, there was 
absolutely no relationship between yields and uptake as measured by 
cotinine. And then, as you follow the studies from 1981 through to 1994, 
there seems to be a growing tendency toward an association of some sort, 
and at the end you pointed out there was a shallow slope. Is this just a 
spurious change with time, or do you feel this may be related to changes in 
product characteristic because, obviously, the product that was smoked in 
1981 is not the product that is smoked in 1994. 
DR. BENOWITZ: Yes, when you look at the earlier studies, they show 
basically the same slope that studies that were done in 1989 and 1990 are 
showing. So, I think when we have a large enough population, we are 
probably seeing it even back in the 1980's. Prior to that, 1 have no idea. 
DR. BOCK: Dr. Benowitz, you were quoted as saying something to the effect 
that compensation over the long term does not appear to be persistent. Is 
that your opinion? 
DR. BENOWITZ: Fhat statement was made in dealing with the question of 
when people are shifting from one cigarette to a lower yield cigarette, will 
there be permanent overcompensation? And the only studies that 1 found (1 
think Dr. Kozlowski is going to talk about these) looked at carbon monoxide 
levels and the amount of compensation. At least in one study, carbon 
monoxide levels went up and then went down again. 
But if you look at the issue of compensation broadly, how do you 
interj)ret the fact that people smoke a cigarette with an FFC yield of .2 the 
same as the one that has the FFC nicotine yield of 1 .5, and tliey have the 
same nicotine cotinine levels? If you do not call it comj)ensation, you have 
to think of something to call it. 
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