Electronic cigarettes may help smokers quit, but continued use increases the chances of relapse, based on a 2-year study of French smokers. Findings were recently published in JAMA: Internal Medicine and suggest that e-cigarettes may be useful for initial quit attempts but do not provide a long-term solution for smoking cessation.

First started in 2012, the CONSTANCES study (Consultants des Centres d’Examens de Santé) tracked the health of nearly 7,500 current and former smokers in France. For roughly 2 years, participants completed surveys about their health and lifestyle, which included their tobacco and e-cigarette use.

E-cigarettes are battery-operated devices that heat up liquid nicotine into a vapor that can be smoked. They’re not a safe alternative to tobacco cigarettes. However, many smokers use them to cut back or quit, despite controversial evidence about their impact on smoking cessation.

The recent analysis included a total of 5,400 current daily smokers and 2,025 former smokers who had recently quit. Participants were in their mid-40s, on average, and about half were women.

Among those who were smokers at the start of the study, analysis showed that individuals using e-cigarettes were 67% more likely to report quitting smoking over the next 2 years compared to non e-cigarette users. Regular e-cigarette use was also associated with a greater reduction in the average number of cigarettes smoked daily throughout the study period.

However, among the participants who had already quit at the start of the study, e-cigarette use was associated with 70% greater risk of resuming use of tobacco use over the next 2 years.

What findings suggest, according to authors, is that there is a small window where e-cigarettes may be helpful for smoking cessation. When first reducing or eliminating tobacco cigarettes, e-cigarette can help satisfy the habit and reduce dependence on nicotine. However, when e-cigarettes are used longer-term, it’s likely that nicotine dependence is simply maintained and smokers may lose motivation to quit. For this reason, experts note that additional tools are likely needed, beyond e-cigarettes, to eliminate all cigarette use to promote better health.