Smoking and Tobacco Control Monograph No. 7 
QUESTION-AND-ANSWER SESSION 
DR. BENOWITZ: How do you reconcile the differences between your data 
and other data that show when you get down to very low yields of nicotine, 
you are getting to a cotinine level of 225 vs. maybe 325 or so at the higher 
levels, in over 2,000 people. Do you think that is less accurate than your 
data in 33 subjects? 
DR. DEBETHIZY: 1 think that the method of measuring plasma cotinine is 
a less accurate measure of nicotine uptake. 
DR. BENOWITZ: What bias do you think there is in cotinine that could 
explain the tremendous difference in findings? 
DR. DEBETHIZY: 1 do believe the data that we have. And 1 am surprised at 
them, based on what 1 know about the cotinine data in the field studies. 
Now, that does not mean that the data we have are wrong; it may be that 
at lower yielding products, that what people do over the course of an entire 
24-hour period is different from what would be measured, say, at either 
9:00 o'clock in the morning or 3:00 o'clock in the afternoon, depending 
on where people are measuring those plasma samples. So, 1 would say that, 
yes, the number is much larger for those plasma cotinine studies. But the 
point is that, even with those studies, compensation is incomplete. People 
smoking lower yielding cigarettes absorb less nicotine. Now, 1 would 
conclude the same thing from both data sets. 
DR. BENOWITZ: 1 want to go back to your statement when you said the 
FTC method is accurately reflecting intake, because 1 think that is patently 
wrong. It is not whether there is some reduction; it is whether you can look 
at those cotinine levels, which would indicate that, when you get below 1 mg 
nicotine, that the FTC method is underestimating consistently based on 
cotinine levels in a couple of thousand people. 
What ! am arguing about is, is it reasonable to generalize from your 
33 subjects and say that is more valid than the 2,000? 
Cotinine levels, as you know, vary throughout the day, but not more 
than 10 or 15 percent if you are smoking regularly. So, there is no way that 
10 or 15 percent can explain the difference, even if there were the worst bias 
that you can imagine. 
DR. DEBE'I’HIZY: 1 think that we can generalize from the data. I do not 
think we can give those data the weight that 10 years of analysis has 
provided us with. But I think that if we look at the [)lasma cotinine data, 
peo[)le smoking lower yielding cigarettes absorb less nicotine. I'hose data 
clearly show that. 
1 hey do not show that peo[)le get the same amount of material from all 
the wide range of nicotine-yielding cigarettes; would you agree with that? 
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