Cigarette smokers who attempted to stop smoking with electronic cigarettes and behavioral support were almost twice as likely to be abstinent a year later than those using nicotine-replacement therapies (NRT), a randomized trial showed.
British researchers randomly assigned adults attending U.K. National Health Service stop-smoking services to receive either NRT products of their choice, including combinations of products, provided for up to 3 months, or an e-cigarette starter pack (e-liquid strength, 18 mg/mL) with instructions to purchase further e-liquids in the flavors and nicotine strength of their choice. Both groups were also offered weekly behavioral support, reported Dunja Przulj, PhD, of Queen Mary University in London, and colleagues.
A year later, the sustained abstinence rate was almost twice as high among the smokers randomized to the e-cigarette group: 18.0% versus 9.9% (relative risk 1.83, 95% CI 130-2.58, P<0.001), they wrote in the New England Journal of Medicine.
In an email to MedPage Today, Przulj said the study findings confirm that e-cigarettes are an effective way for smokers to quit smoking.
But in an accompanying editorial, Belinda Borrelli, PhD, and George T. O’Connor, MD, both of Boston University, noted that while just 9% of study participants in the NRT arm who were not smoking 1 year after randomization were still using nicotine replacement, 80% of those who stopped smoking using e-cigarettes were still vaping 1 year later.
“This differential pattern of long-term use raises concerns about the health consequences of long-term e-cigarette use,” they wrote, adding that e-cigarette vapor has been shown to contain toxins that have the potential to negatively impact human cells.
They further noted that early studies in mice and humans suggested that these biologic effects impact lung function, although to a lesser extent than cigarette smoking. And, the editorialists worried about second-hand effects on children of those who continue vaping. Not only could those include direct health impacts, but children could also pick up the habit themselves from viewing parents as role models.
“These findings argue against complacency in accepting the transition from tobacco smoking to indefinite e-cigarette use as a completely successful smoking-cessation outcome,” Borrelli and O’Connor wrote.
The randomized trial originally included 886 participants recruited at three NHS smoking cessation service sites from May of 2015 to February of 2018. Adult smokers were invited to participate if they were not pregnant or breast-feeding, had no strong preference to use or not use NRT or e-cigarettes, and were not using either type of product at recruitment.
Those randomized to the e-cigarette arm of the trial received a second-generation refillable e-cigarette with one 30 ml bottle of nicotine e-liquid. They were encouraged to purchase future e-liquids online or from local vape shops, and to experiment with different nicotine strengths and flavors if the provided e-liquid did not meet their needs.
Participants in the NRT group were informed about the range of products available (gum, patch, lozenge, nasal spray, inhalator, mouth spray, mouth strip, and microtabs) and they selected their preferred product.
Combination use — typically a patch and fast-acting oral NRT — was encouraged. Participants could also switch products during the trial.
The behavioral therapy was offered to both treatment groups as weekly one-on-one sessions delivered for at least 4 weeks after the quit date.
Participants were contacted by telephone at weeks 26 and 52, and interviewers asked about product use and smoking abstinence. Respondents who reported abstinence or a reduction in smoking of at least 50% at 52 weeks were invited back to provide carbon monoxide readings to confirm smoking status.
Overall, adherence was similar in the two groups, but e-cigarettes were used more frequently and for longer than nicotine replacement over 52 weeks (63 of 79 e-cigarette users who quit smoking were still vaping at 1-year vs four of 44 NRT users who quit smoking cigarettes).
“Both e-cigarettes and nicotine-replacement were perceived to be less satisfying than cigarettes,” the researchers wrote. “However, e-cigarettes provided greater satisfaction and were rated as more helpful to refrain from smoking than nicotine-replacement products.”
They also found that e-cigarette users reported more throat and mouth irritation (65.3% vs 51.2% ) and NRT users reported more nausea (37.9% vs. 31.3% in the e-cigarette group).
The e-cigarette group reported greater declines in cough and phlegm production from baseline to 52 weeks (RR 0.8 for cough, 95% CI 0.6-0.9; RR 0.7 for phlegm, 95% CI 0.6-0.9).
No significant between-group differences were seen in wheezing or shortness of breath.
Przulj and colleagues noted that the trial showed a larger impact for e-cigarette use on smoking cessation than has been reported in previous studies, possibly due to the recruitment of motivated smokers seeking cessation treatment, the availability of face-to-face support, and the use of second-generation e-cigarettes that tend to have higher nicotine levels than first-generation products.
The researchers conceded that the high rate of continuing e-cigarette use among those who stopped smoking cigarettes “can be seen as problematic if e-cigarette use for a year signals ongoing long-term use which may pose as-yet-unknown health risks.”
“Among participants in our trial in whom full abstinence was not achieved, those in the e-cigarette group were more likely to reduce their smoke intake than those in the nicotine-replacement group, but it is unclear whether this affects future abstinence,” they added.
The study was funded by the National Institute for Health Research and Cancer Research UK.
Przulji disclosed support from Pfizer. Co-authors disclosed multiple relevant relationships with industry, including Pfizer and Johnson & Johnson.