Cigarette ignition propensity, smoking behavior, and toxicant exposure: A natural experiment in Canada

BACKGROUND: This study used a 'pre-post' research design to measure the impact of the Canadian reduced ignition propensity law on cigarette toxicity and smoking behavior among Canadian smokers. METHOD: The study was conducted in Ontario, Canada over a ten-month period in 2005-2006, consisting of 4 laboratory visits (baseline N = 61, final N = 42). At Visit 1, questionnaire data and biospecimens were collected. During the following 24 hours, participants smoked 5 cigarettes ad libitum through a topography recording device and collected their cigarette butts. Visit 2 consisted of a questionnaire and smoking one cigarette to measure laboratory topography values. After ten months, these procedures were repeated. RESULTS: Generalized estimating equations, with law status (pre and post) as a fixed within-subject factor, were used to determine changes in behavior and biomarker exposure. Overall, there were no significant differences in smoking topography, breath carbon monoxide, and saliva cotinine pre-post law (p>0.1). However, analyses revealed a significant increase in the summed concentrations of hydroxyfluorene metabolites (N = 3),, and 1-hydroxypyrene in urine, with at notable increase in hydroxyphenanthrene metabolites (N = 3) (p(Σhydroxyfluorene )= 0.013, 22% increase; p(1-hydroxypyrene )= 0.018, 24% increase; p(Σhydroxyphenanthrene )= 0.061, 17% increase). CONCLUSION: While the results suggest no change in topography variables, data showed increases in exposure to three PAH biomarkers following reduced ignition propensity implementation in Canada. These findings suggest that human studies should be considered to evaluate policy impacts.