A review in the Canadian Medical Association Journal (CMAJ) reveals that Imperial Tobacco Canada attempted to destroy documents that contained high-quality scientific evidence that cigarette smoke was carcinogenic and addictive. These studies had significant implications for government tobacco-control programs.
This is the opening analysis of the 60 scientific reports dating from 1967 to 1984. They were destroyed in Canada in 1992 but stored at British American Tobacco headquarters in the United Kingdom. “The research standards of the studies reported in the destroyed documents was equal to and, in many cases, exceeded the standards of peer-reviewed scientific research published during the same period,” explains Dr. David Hammond, University of Waterloo, and coauthors. “The destroyed documents reveal a vast body of scientific evidence on the health effects of smoking.”
On September 28, 2009, the province of Ontario launched a $50 billion lawsuit against Imperial Tobacco. In addition, British Columbia and New Brunswick have also filed lawsuits against the company.
Several of the destroyed documents report the carcinogenic components of tobacco smoke and describe testing for differences between tobacco brands (which differed little in their carcinogenic activity). Other studies considered the effect of filters. Findings indicated that rats exposed to smoke through filters had more particles in their lungs than rats with less filtered smoke. This contradicted the original hypothesis. As a report by one senior research scientist explained, smokers were inhaling more smoke to get a similar amount of nicotine.
The authors write: “In fact, epidemiologic data indicates that the rise of ventilated cigarettes in Western countries coincided with an increase in the rate of adenocarcinoma, perhaps because of deeper inhalation patterns from these products.”
A total of eleven of the destroyed documents focused on original research about the effects of second-hand smoke. Most of the experiments were performed on rats. These studies indicated cellular changes from second-hand smoke. The authors write: “The scientists concluded that second-hand smoke was in fact more toxic than mainstream smoke “especially for low delivery cigarettes.””
The authors write in conclusion: “The destruction of the documents by Imperial Tobacco Canada has direct implications for industry liability and new litigation that is proceeding in Canada.” They note: “Canadian courts are currently being asked to consider whether the tobacco industry should be liable for the health care costs attributable to smoking.”
“Destroyed documents: uncovering the science that Imperial Tobacco Canada sought to conceal”
David Hammond , Michael Chaiton , Alex Lee , Neil Collishaw
CMAJ 10.1503/cmaj.080566
Canadian Medical Association Journal
Written by Stephanie Brunner (B.A.)