Nicotine yield from machine-smoked cigarettes and nicotine intakes in smokers: Evidence from a representative population survey

Background: The relevance of nicotine yields from machine-smoked cigarettes for quantifying smokers' nicotine intakes and exposure to cigarette toxins has been called into question. However, most studies of the relationship b etween nicotine yield and nicotine intake have been on relatively small and unrepresentative samples and have included few smokers of "ultra-low" bran ds (i.e., those yielding around 1 mg of tar and 0.1 mg of nicotine). Method s: We examined the relationship between salivary cotinine (a major metaboli te of nicotine) concentrations and nicotine yields of machine-smoked cigare ttes in a nationally representative sample of 2031 adult smokers of manufac tured cigarettes surveyed in the 1998 Health Survey for England. We used st andard linear regression techniques to examine associations and two-sided t ests of statistical significance. Results: Cotinine concentrations varied w idely between smokers at any level of nominal brand nicotine yield. On aver age, cotinine levels were slightly lower in smokers of lower nicotine-yield ing brands, but these smokers differed in terms of sex, socioeconomic profi le, and cigarette consumption. After we controlled for potential confounder s, nicotine yield from the brand smoked accounted for only 0.79% of the var iation in saliva cotinine concentrations. Nicotine intake per cigarette smo ked, as estimated from salivary cotinine level, did not correspond with mac hine-smoked yields at any level of nicotine yield. Nicotine intake per ciga rette was about eight times greater than machine-smoked yields at the lowes t deliveries (1.17 mg estimated nicotine intake per cigarette from brands a veraging 0.14-mg delivery from machine smoking) and 1.4 times greater for t he highest yield cigarettes (1.31-mg estimated nicotine intake per cigarett e from brands averaging 0.91 mg from machine smoking). Conclusions: Smokers ' tendency to regulate nicotine intake vitiates potential health gains from lower tar and nicotine cigarettes. Current approaches to characterizing ta r and nicotine yields of cigarettes provide a simplistic guide to smokers' exposure that is misleading to consumers and regulators alike and should be abandoned.