Switching people who smoke to unfiltered cigarettes: Effects on smoking topography.

Introduction: Smoking topography (ST) describes smoking behavior and patterns. Removal of the cigarette filter and subsequent impact on ST has not been investigated. This is the first clinical trial comparing ST for filtered and unfiltered cigarettes in a naturalistic experiment. Methods: We conducted a crossover clinical trial following established people who smoke cigarettes (n = 32) for two weeks under filtered and unfiltered smoking experimental conditions. Participants (50 % female, mean age 38.3 yr.) smoked in each experimental condition followed by a 3-week post-washout period. ST (puff count, volume, duration, peak and average flow) was measured at six time-points. Statistical analysis included a linear repeated mixed-effects model of smoking experimental conditions by visit number and sex. Results: Average flow (ml/sec) was significantly less for filtered smoking (-6.92 lower (95 % CI: -13.44 to -0.39), p Conclusion: Lower average flow rates were associated with filtered cigarette smoking. No significant differences were found for other ST variables between smoking experimental conditions. ST measurements comparing cigarette smoking conditions may determine if product regulatory changes, such as removing the cigarette filter could impact smoking behavioral patterns among people who smoke. This proof-of-principle study measuring ST may be replicated in larger trials to determine potential behavioral changes in smoking unfiltered cigarettes.