Study finds failure to sustain reductions in carcinogens in cigarettes

Waterloo, Ontario: Tobacco-specific nitrosamines (TSNAs) are potent carcinogens formed predominantly during the cigarette manufacturing process. Despite initial success lowering TSNA levels in cigarettes sold in Canada, following subsidies by the Ontario government to manufacturers in 2000, a study published today in the journal Nicotine & Tobacco Research has found that the decrease in TSNAs have not been sustained.

The authors reviewed TSNA levels in unburned tobacco and in tobacco smoke from cigarettes produced by manufacturers that constitute 90% of Canada's cigarette market. Following initial reductions, TSNA levels in cigarettes sold in Canada consistently increased after 2007. By 2012, the levels were 2 to 40 times higher than those observed in 2007.

Though TSNA levels at the end of the study period were still below those before government subsidies, the increases raise several important issues. "Overall, the findings indicate alarming increases in the TSNA levels of cigarettes sold in Canada," says co-author Dr. David Hammond, researcher at the School of Public Health & Health Systems at the University of Waterloo. While the increases in TSNAs should not be interpreted as a direct increase in health risk, Hammond says "manufacturers bear a responsibility to minimize consumer exposure to potent carcinogens to the fullest extent possible. The failure to sustain these reductions signifies a lack of commitment towards harm reduction."