Clinical Trial Evidence: E-Cigarettes Aid Smoking Cessation/Reduction

A new clinical trial provides clear evidence that e-cigarettes are effective in helping smokers quit or reduce cigarette consumption.  The results were published in PLoS One by Pasquale Caponnetto and colleagues at the University of Catania (Italy) (available here). 

Dr. Caponnetto enrolled 300 smokers who were not interested in quitting, and split them into three groups. Each group received free e-cigarettes with a different fluid for 12 weeks: Group A received 7.2 mg. nicotine cartridges; Group B got 7.2 mg. cartridges for 6 weeks followed by 5.4 mg. cartridges for six weeks; Group C received flavored cartridges with no nicotine.  Participants returned every two weeks through week 12, when the intervention formally ended; follow-up occurred at weeks 24 and 52.  At each visit, investigators measured cartridge use, cigarette consumption and exhaled carbon monoxide levels; they also measured saliva levels of cotinine, a nicotine metabolite and marker, at weeks 6 and 12.

At week 12, 33% of participants reported that they had reduced cigarette consumption by half or more, or had quit smoking completely.  At one year, 10% reported smoking reduction and 8.7% reported complete cessation.  Two problems commonly associated with smoking cessation were gauged: withdrawal symptoms were seen only occasionally; weight gain was not observed at all.  Other than some throat irritation reported in the first two weeks in Groups A and B, no other complaints were voiced. 

Why wasn’t the success rate higher?  A significant factor was a low rate of satisfaction with the products used in the trial.  Caponnetto and colleagues comment that “Many respondents complained of the frequent failures, lack of durability, difficulty of use (it takes time to familiarize with the puffing technique), and poor taste of the product tested.”  Substantial improvements in e-cigarette design and function have been observed since the trial was initiated in 2010, suggesting that satisfaction rates, and therefore cessation/reduction rates, might be higher if the study were to be repeated today.

Only about 60% of smokers completed the study, which confirms the difficulty of using the clinical trial model for evaluating consumer behavior.  I am familiar with these challenges.  In 1995, at the University of Alabama at Birmingham, I directed the first-ever clinical trial employing tobacco harm reduction; our results were published in the American Journal of Medicine (abstract here).  We enrolled 63 smokers in a pilot study in which we recommended that they switch to Skoal Bandits, the only widely available pouched smokeless tobacco product at that time.  At one year, 31% of men and 19% of women had attained smoking cessation, for an overall success rate of 25%. An additional 7% of subjects had reduced their cigarette consumption by at least 50%.  Unlike the current study, nearly all of our smokers wanted to quit, but had failed repeatedly with nicotine replacement therapy, which was available only through prescription at that time.  

The current study is well designed and well executed.  These were hard-core smokers with no interest in quitting, yet one year later almost one in five smoked fewer cigarettes or none at all.  Caponnetta and colleagues provide solid evidence that e-cigarettes can accelerate the worldwide transformation in tobacco use (described here  ).