AIMS : To examine if changes in select measures of e-cigarette puffing topography are associated with changes in smoking behavior.

METHODS : Sixteen current cigarette smokers were instructed to completely switch from smoking combustible cigarettes to using e-cigarettes over a two-week period. The study was completed in the Southern Midwestern region of the United States. Measures included demographics, smoking history, and cigarette dependence, as well as baseline and two-week follow-up self-reported cigarettes per day, cigarette craving and urges, exhaled carbon monoxide readings, and e-cigarette usage data (puff number, puffing time, and average puff duration) collected via the e-cigarette built-in puff counter.

RESULTS : Over the two-week switching period, participants significantly reduced their cigarettes per day (~80% reduction, p<.0001). While the number of e-cigarette puffs/day remained relatively stable (p>.05), the average total e-cigarette daily puffing time increased significantly (p=0.001). Users' average puff duration increased by 91ms/puff/day (p<0.001). The percentage decrease in cigarettes smoked per day was significantly and directly related to the slope of subjects' average puff duration over time (r(13)=0.62,p=0.01), such that as cigarettes per day decreased, puff duration increased. Self-reported smoking urges remained relatively stable from baseline to the end of the two-week period (p>.05).

CONCLUSIONS : Among smokers switching to an e-cigarette, greater increases in e-cigarette puff duration was associated with greater reductions in cigarette smoking.