Article Text

Download PDFPDF

Softening up on the hardening hypothesis
  1. Joanna E Cohen1,2,
  2. Paul W McDonald2,3,
  3. Peter Selby4
  1. 1Institute for Global Tobacco Control, Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
  2. 2Ontario Tobacco Research Unit, Toronto, Waterloo, Canada
  3. 3School of Public Health and Health Systems, University of Waterloo, Waterloo, Canada
  4. 4Centre for Addiction and Mental Health, Addictions Program, Toronto, Ontario, Canada
  1. Correspondence to Dr Joanna E Cohen, Director, Institute for Global Tobacco Control, Bloomberg Associate Professor of Disease Prevention, Johns Hopkins Bloomberg School of Public Health, 624 N Broadway, Hampton House 297, Baltimore, MD 21205-1996, USA; jocohen{at}

Statistics from

The hardening hypothesis has intuitive and common sense appeal: in jurisdictions that have implemented evidence-based tobacco control policies, the smokers who have a relatively easy time quitting will quit, and as the future unfolds there will be an increasing proportion of remaining smokers who cannot quit and are more resistant to quitting than smokers in the past.

In this context, ‘hardening’ is a measure of a group, or population, over time. If a group or population is hardening, it implies that the proportion of smokers who are ‘hard core’ is increasing.

‘Hard core’ was first used in the peer reviewed literature in relation to smokers by Lichtenstein and Keutzer in 1973, in their review of how psychological research could be applied in smoking cessation clinics.1 Following this initial intimation of a hard core smoker, the term popped up again in the late 1980s,2–5 and since then the literature on hard core smokers has grown, although the number of papers that have empirically examined this topic remains limited.

The bottom line from the body of evidence to date is that smokers classified as hard core represent only a very small minority of all smokers (in selected high income countries for which data have been available), and that ‘hardening of the target’ is still a long way off. Even analyses focused on the individual level find only a handful of subgroups where there is a suggestion of hardening. Cross-sectional data show that the lower the prevalence of smoking, the lower the average number of cigarettes smoked per day and the lower the percentage of smokers who smoke within 30 min of waking.6 Similarly, …

View Full Text

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Linked Articles