Can electronic cigarettes increase smoking cessation? : a systematic review

Abstract

Background: Over the past ten years or so, there is a huge increase in the popularity of electronic cigarettes around the world. Some people regard e-cigarettes as a tobacco substitute and use them to help smoking abstinence and relieve nicotine withdrawal symptom. On the other hand, there are those who believe that e-cigarettes should not be promoted since safety and efficacy of these battery-operated devices are still under investigation. Hence, this project aims to evaluate the effect of using electronic cigarettes to quit smoking among the conventional smokers. Methods: This project used key words to search on PubMed, MEDLINE, The Cochrane Library, 中国知网(CNKI), EMBASE, and BBCNEWS. Eventually, a total of 111 items in PubMed, 6 in The Cochrane Library and 23 were obtained in CNKI. After the screening process, finally 11relevant papers were reviewed in this project. There were two randomized controlled trials on evaluating the effect of reducing smoking with e-cigarettes. Five surveys(Survey 1-5) analyzed users’ satisfaction and their original expectations on trying electronic cigarettes. Two proof-of-concept trials also assessed the effect of using e-cigarettes on reducing and quitting smoking. In addition, a qualitative study and a case series study provided evidence on interpreting whethere-cigarettes could help smoking abstinence. Results: Brown et al. 10conducted a RCT and showed that in an intention to treat analysis, combined ≥50% smoking reduction and complete smoking abstinence was shown in 33% (99/300) at 12 weeks and 19% (57/300) at 52 weeks. Another RCT conducted by Bullen et al. showed the continuous abstinence at 1 month was23.2%in nicotine e-cigarettes group and15.9%in nicotine patches group and 16.4%in placebo e-cigarettes group; at 3 month, the rateswere13.1%, 9.2% and 6.8%; at 6 months, the rates were 7.3%, 5.8% and 4.1%.In survey 1 (Etter), satisfaction of helping smokers quit was79%; in survey 2 (Kralikova et al.), satisfaction of helping quit was over 60%; in survey 3 (Dawkins et al. 14), participants reported their situation of smoking cessation: 38% for >1 year, 19% for 6-11 months, 43% for < 6months;in survey 4 (Etter and Bullen), 92% current smokers and 96%former smokers reported ECs were effective to reduce their smoking consumption; in survey 5 (B. Siegel et al. ), 66.8% smokers reported it helped quitting smoking. In two proof-of-concept trials, sustained quitting more than 50% including quitter accounted for 55% and 64.3%.Thequalitative study and the case series study indicated that ECs were modestly effective to reduce smoking consumption with less toxic effects. Conclusion: There is some preliminary evidence from11studiesthatelectronic cigarettes could be effective for reducing conventional smoking consumption within a short period. Because there is a lack of adequate and long-term randomized controlled trials to assess the safety and efficacy of e-cigarettes, particularly in comparison to nicotine replacement therapy, government regulations should be established to control e-cigarettes and to the claim that e-cigarettes can be used as a standard as nicotine smoking cessation aid.