Aims: To use a unique longitudinal data set to assess the association between e-cigarette use while smoking with smoking cessation attempts, cessation and substantial reduction, taking into account frequency of use and key potential confounders.
Design: Web-based survey, baseline November/December 2012, 1-year follow-up in December 2013.
Setting: Great Britain.
Participants: National general population sample of 4064 adult smokers, with 1759 (43%) followed-up.
Measurements: Main outcome measures were cessation attempt, cessation and substantial reduction (≥50% from baseline to follow-up) of cigarettes per day (CPD). In logistic regression models, cessation attempt in the last year (analysis n = 1473) and smoking status (n = 1656) at follow-up were regressed on to baseline e-cigarette use (none, non-daily, daily) while adjusting for baseline socio-demographics, dependence and nicotine replacement (NRT) use. Substantial reduction (n = 1042) was regressed on to follow-up e-cigarette use while adjusting for baseline socio-demographics and dependence and follow-up NRT use.
Findings: Compared with non-use, daily e-cigarette use at baseline was associated with increased cessation attempts [odds ratio (OR) = 2.11, 95% confidence interval (CI) = 1.24-3.58, P = 0.006], but not with cessation at follow-up (OR = 0.62, 95% CI = 0.28-1.37, P = 0.24). Non-daily use was not associated with cessation attempts or cessation. Daily e-cigarette use at follow-up was associated with increased odds of substantial reduction (OR = 2.49, 95% CI = 1.14-5.45, P = 0.02), non-daily use was not.
Conclusions: Daily use of e-cigarettes while smoking appears to be associated with subsequent increases in rates of attempting to stop smoking and reducing smoking, but not with smoking cessation. Non-daily use of e-cigarettes while smoking does not appear to be associated with cessation attempts, cessation or reduced smoking.
Keywords: Electronic cigarettes; electronic nicotine delivery systems; harm reduction; quit attempts; smoking cessation; tobacco.
© 2015 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.