title: "Hardcore" definitions and their application to a population-based sample of smokers.
abstract: BACKGROUND
  As smoking prevalence declines, some suggest that so-called "hardcore" smokers will come to represent a growing and irreducible proportion of current smokers ("hardening hypothesis"). Different definitions of a "hardcore" smoker have been used in the literature. This paper describes population-based definitions of "hardcore" smokers and compares estimates of the prevalence of "hardcore" smokers derived using these definitions.
  
  
  METHODS
  Definitions identified in a comprehensive literature search were reduced to their component constructs. We estimated the prevalence of "hardcore" smokers as a proportion of all current adult smokers in Ontario, Canada, using data from the Ontario Tobacco Survey (2005-2008; N = 4,130). Definition concordance was examined using bivariate cross-tabulations.
  
  
  RESULTS
  Six definitions were identified in the literature. Five definitions included constructs of quit intentions and quit attempts, four included nicotine dependence, three included long-term use, and one included a measure of smoker knowledge about smoking hazards and confronting substantial societal disapprobation of smoking. Estimates of "hardcore" smoker prevalence in Ontario based on these definitions ranged from 0.03% to 13.77%.
  
  
  CONCLUSIONS
  Estimates of the prevalence of "hardcore" smokers in Ontario varied considerably between the six definitions of the "hardcore" smokers found in the population-based literature. This study underscores the need for consensus on the best definition of "hardcore" smoker.
authors.affiliation: Ontario Tobacco Research Unit, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Costa
authors.forename: Joanna E
authors.initials: JE
authors.lastname: Cohen
authors.forename: Michael O
authors.initials: MO
authors.lastname: Chaiton
authors.forename: David
authors.initials: D
authors.lastname: Ip
authors.forename: Paul
authors.initials: P
authors.lastname: McDonald
authors.forename: Roberta
authors.initials: R
authors.lastname: Ferrence
mesh_terms: D002170:Canada / Q000453:epidemiology; D006801:Humans; D009864:Ontario / Q000453:epidemiology; D044382:Population Groups / Q000706:statistics & numerical data; D012907:Smoking / Q000453:epidemiology*