Perceived relative harm of electronic cigarettes over time and impact on subsequent use. A survey with 1-year and 2-year follow-ups

Drug Alcohol Depend. 2015 Dec 1:157:106-11. doi: 10.1016/j.drugalcdep.2015.10.014. Epub 2015 Oct 22.


Introduction: Media presentations of e-cigarettes may affect perception of the devices which may influence use.

Objectives: To assess in a cohort of past-year smokers (1) if perceived harm of e-cigarettes relative to cigarettes changed over time, (2) predictors of perceived relative harm, (3) if perceived relative harm predicted subsequent e-cigarette use among never-users.

Methods: Longitudinal web-based survey of a general population sample of British smokers and ex-smokers, waves in 2012 (n=4553), 2013 and 2014 (44%, 31% response rate, respectively). Changes over time were assessed using Friedman and McNemar tests, n=1204. Perceived relative harm at wave 3 was regressed onto perceived relative harm at waves 1 and 2, while adjusting for socio-demographics and change in smoking and e-cigarette status, n=1204. Wave 2 e-cigarette use among 1588 wave 1 never-users was regressed onto wave 1 socio-demographics, smoking status and perceived relative harm.

Results: Perceived relative harm changed (χ(2)=20.67, p<0.001); the proportion perceiving e-cigarettes to be less harmful than cigarettes decreased from 2013 to 2014 (χ(2)=16.55, p<0.001). Previous perception of e-cigarettes as less harmful, having tried e-cigarettes and having stopped smoking between waves predicted perceiving e-cigarettes as less harmful than cigarettes. Perceiving e-cigarettes to be less harmful than cigarettes predicted subsequent use, adjusting for other characteristics (OR=1.39; 95% CI: 1.08-1.80, p=0.011).

Conclusion: Among a cohort of smokers and ex-smokers, accurately perceiving e-cigarettes as less harmful than smoking predicted subsequent e-cigarette use in never-users; this perception declined over time. Clear information on the relative harm of cigarettes and e-cigarettes is needed.

Keywords: Behavior; Electronic cigarettes; Harm; Nicotine; Tobacco.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Attitude to Health*
  • Electronic Nicotine Delivery Systems / adverse effects
  • Electronic Nicotine Delivery Systems / psychology*
  • Female
  • Follow-Up Studies
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Perception
  • Smoking / adverse effects
  • Smoking / epidemiology
  • Smoking / psychology*
  • Smoking Cessation / statistics & numerical data
  • Surveys and Questionnaires
  • Time Factors
  • United Kingdom / epidemiology
  • Young Adult