Previously secret tobacco industry documents show why you can't trust claims of additive safety (including menthol)

Today my colleagues Marcia Wertz, Thomas Kyriss, Sumi Paranjape, and I published a paper in PLoS Medicine that reanalyzes data from Philip Morris' “Project MIX,” which included chemical analyses and animal toxicology studies of 333 cigarette additives that Philip Morris published in the journal Food and Chemical Toxicology in 2002.

We used documents made public as a result of litigation against the tobacco industry (and available to all on the UCSF Legacy Tobacco Documents Library) to investigate the origins and design of Project MIX, and to conduct our own analyses of the results. The documents revealed post-hoc changes in analytical protocols after the industry scientists found that the additives increased cigarette toxicity by increasing the number of particles in the cigarette smoke. We found that in the original Project MIX analysis, the published papers obscured findings of toxicity by adjusting the data by Total Particulate Matter concentration: when we conducted our own analysis by studying additives per cigarette, we found that 15 carcinogenic (cancer-causing) chemicals increased by 20% or more.

We also found that the failure to identify many toxic biological effects was because the studies Philip Morris carried out used too few rats to reliably detect toxic effects. Our analysis of Philip Morris' data provides evidence for the elimination of the use of the studied additives (including menthol) from cigarettes on public health grounds; we concluded  “The results demonstrate that toxins in cigarette smoke increase substantially when additives are put in cigarettes, including the level of [Total Particulate Matter]. In particular, regulatory authorities, including the [Food and Drug Administration] and similar agencies elsewhere, could use the Project MIX data to eliminate the use of these 333 additives (including menthol) from cigarettes.” 

The paper is available here. 

A video describing the results is available here.

Philip Morris objected to our conclusions, but ignored the central points of our paper; read their criticism and our response here.

A German translation of the full paper is here. 

Translations of the abstract into Chinese, French, Finnish, Spanish and Russian are also available. The UCSF press release on the study is here.