After 6 weeks, their exhaled carbon monoxide levels were 45% lower and were still low 4 weeks later.

After 6 weeks, their cigarettes per day was reduced by two-thirds and was still low 4 weeks later.

Abstract

Objectives Switching from combustible tobacco cigarettes to electronic cigarettes (e-cigs) may or may not help smokers to reduce cigarette consumption and toxicant exposure. This pilot study investigated the effects of asking smokers to switch to e-cigs for 6 weeks on smoking, exhaled carbon monoxide (CO) concentration, dependence, and motivation to quit smoking.

Methods Non-treatment seeking daily smokers (n = 18) were given free e-cigs and instructed to use them instead of smoking cigarettes for 6 weeks. Smokers were assessed at baseline, weekly for 6 weeks, and at 8 and 10 weeks for cigarettes/day, e-cig use, CO, cigarette dependence, and Contemplation Ladder.

Results All participants completed 6 weeks; 17 completed 10 weeks. At Week 6, cigarettes/day were reduced by two-thirds and CO by 45% from baseline (p's < .001), with reductions maintained at Week 10 (p's < .005). Cigarette dependence scores were a third lower at Weeks 6 (p < .002) and 10 (p < .001) than at baseline. Contemplation Ladder scores were higher at Weeks 6 and 10 (p's < .001) than at baseline. All these statistical effect sizes were large. At Week 6, number of reasons not to use e-cigs increased (p < .011).