People who use e-cigarettes daily while continuing to smoke seem to be more likely to try to quit and smoke less, but they are no more likely to actually stop smoking, according to a web-based survey of smokers in Great Britain.

In the study, 43.7 per cent of the 508 smokers who did not use e-cigarettes at baseline attempted to quit during the next year. This compares to 52.5 per cent of 124 people using e-cigarettes“non-daily”and 64.9 per cent of the 48 daily users.

Compared with nonusers, people using e-cigarettes daily were twice as likely to make a quit attempt during the next year (odds ratio 2.11) after adjusting for confounders. However, using e-cigarettes daily did not significantly increase the likelihood that the person would quit. Using e-cigarettes less frequently than daily did not increase the likelihood of cessation attempts or success.

Using e-cigarettes daily reduced cigarette consumption: 5.7 per cent of smokers not using e-cigarettes at follow-up, 5.5 per cent of non-daily e-cigarette users and 13.9 per cent of daily users at least halved their cigarette consumption. Daily e-cigarette use at follow-up doubled the chance that the smoker had at least halved their cigarette consumption (OR 2.49). (Addiction doi:10.1111/add.12917)

In contrast, a year-long survey of 1,000 smokers in California found that e-cigarette users were 49 per cent less likely to decrease cigarette consumption by at least 20 per cent during the one-year follow-up compared with smokers who never used e-cigarettes. After a year, e-cigarette users were 59 per cent less likely to have quit for 30 days or more.

E-cigarettes users were 15 per cent more likely to report making a quit attempt, although this was not statistically significant.

“Based on the idea that smokers use e-cigarettes to quit smoking, we hypothesised that smokers who used these products would be more successful in quitting,” said Wael Al-Delaimy of the San Diego School of Medicine. “The research revealed the contrary. We need further studies to answer why they cannot quit. One hypothesis is that smokers are receiving an increase in nicotine dose by using e-cigarettes.” (Am J Public Health doi:10.2105/AJPH.2014.302482)