Last summer the Massachusetts Department of Public Health made headlines with a report that found the nicotine yields of major cigarette brands increased by an average of 10 percent between 1998 and 2004. Last week researchers at the Harvard School of Public Health expanded on that report with a study finding an increase of 8.5 percent between 1997 and 2005. Activists once again cited the trend as evidence of the tobacco companies' secret plot to make cigarettes more addictive and demanded stricter regulation of the industry.
It seems the cigarette makers are not very good at covering their tracks, since they are the source of the data on which both studies were based. (They are required to report the numbers to the Massachusetts Department of Health each year.) In any case, the rise in nicotine yields is not as clear as the industry's critics imply. Anti-smoking activist and tobacco policy blogger Michael Siegel did his own analysis of the data and found "there was no change in the average nicotine yield of Marlboro cigarettes from 1997 to 2006." By contrast, the Harvard study found "a statistically significant increasing trend of 0.013 mg per year" for the 15 Marlboro sub-brands from 1997 to 2005. Philip Morris, for its part, says the nicotine yields of its cigarettes go up and down over the years due to natural variations in tobacco but have not been deliberately raised and have in fact not increased on balance. Over at Slate, Jack Shafer notes that Philip Morris cites variations in the nicotine yields of research cigarettes, which are designed to be as uniform as possible, to back up its point.
Assuming the Harvard researchers are right that nicotine yields are slightly higher now than they were a decade ago, so what? "All cigarettes are highly addictive and deadly, and relatively minor changes in nicotine yield may not significantly alter the product's addictive properties," they write. "The increase in smoke nicotine yield does not necessarily signify any change in exposure within the population of smokers, particularly as human smoking behavior is compensatory and will adjust for differences in smoke yield." (Italics added.)
That last point, which Siegel and Shafer rightly emphasize, is crucial: As with pot smokers and THC, cigarette smokers tend to smoke as much as necessary to get the nicotine dose to which they're accustomed. If you cut the nicotine yield, they will smoke more cigarettes and/or smoke more intensely, taking more puffs per cigarette, inhaling the smoke more deeply, holding it longer, etc. The upshot is that cutting nicotine content, other things being equal, makes cigarettes more dangerous, because it increases the dose of toxins and carcinogens for a given dose of nicotine. Conversely, increasing the nicotine yield while leaving other aspects of the cigarette unchanged should make smoking less hazardous.
So what exactly is troubling about the alleged increase in nicotine yields? Not that cigarettes are more dangerous; if anything, they're slightly safer. Not that cigarettes are more addictive; the data do not even show that smokers are absorbing more nicotine than they did before, and the research on compensatory smoking behavior suggests they aren't. Here is the best the authors of the Harvard study can do: "The product changes described in this report may…represent an effort by tobacco manufacturers to enable persons of lower income to sustain prior levels of nicotine intake, even with a consumption of fewer cigarettes on the assumption that prices would increase due to litigation during this time period." In other words, the cigarette companies, which did not hesitate to screw over smokers when they settled the state tobacco lawsuits, stand accused of trying to cushion the blow of the resulting price increases. The bastards?