Smoke yields of tobacco-specific nitrosamines in relation to FTC tar level and cigarette manufacturer: analysis of the Massachusetts Benchmark Study.

OBJECTIVES: This research assessed the relationship between the deliveries of carcinogenic tobacco-specific nitrosamines (TSNAs) and the Federal Trade Commission (FTC) "tar" ratings of US commercial cigarettes.
METHODS: Analysis of covariance (ANCOVA) was used to assess the explanatory power of FTC tar, the particular manufacturer, and other cigarette characteristics to predict the yields of four TSNAs (N'-nitrosonornicotine [NNN], 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone [NNK], N'-nitrosoanatabine [NAT], and N'-nitrosoanabasine [NAB]) in 26 US commercial brands tested in the 1999 Massachusetts Benchmark Study.
RESULTS: When FTC tar alone was used to predict TSNA yield, the squared correlation coefficient (R(2)) was only 38% for NNN, 76% for NNK, 46% for NAT, and 49% for NAB. Inclusion of manufacturer-specific variables significantly (p < 0.001) increased the estimated R(2) for three of the four species of nitrosamine to: 78% for NNN, 88% for NNK, and 81% for NAT. Inclusion of other cigarette characteristics (filter type, paper permeability, tobacco weight, tip dilution) did not reduce the significance of the manufacturer-specific effects. Federal Trade Commission nicotine and carbon monoxide (CO) yields were no better at predicting TSNA levels.
CONCLUSIONS: FTC ratings for tar, nicotine, and carbon monoxide do not tell the entire story about the comparative yields of toxic agents in marketed cigarette brands. The significant manufacturer-specific effects suggest that proprietary blending and processing of tobacco matter as well. Public, brand-by-brand disclosure of the yields of TSNA and possibly other smoke constituents appears to be warranted.