title: Changes in effectiveness of cigarette health warnings over time in Canada and the United States, 2002-2011.
abstract: BACKGROUND
  Article 11 of the World Health Organization's Framework Convention on Tobacco Control (FCTC) requires countries to implement health warnings on tobacco products. The Article 11 guidelines advise countries to periodically rotate warnings to prevent "wearout" of the health warnings. This study investigates potential wearout of cigarette health warnings during a period of 9 years in 2 countries: Canada, where larger pictorial warnings were implemented approximately 1 year prior to the study, and in the United States, where small text-only warnings were in place for 17 years at the beginning of the study.
  
  
  METHODS
  Data were drawn from national samples of smokers from the International Tobacco Control (ITC) Surveys in Canada (N = 5,309), and the United States (N = 6,412) who were originally recruited by telephone with random digit dialing. Changes in 4 measures of health warning effectiveness and in a composite Labels Impact Index were examined over 8 waves of survey data (2002-2011). Analyses were conducted in 2012.
  
  
  RESULTS
  The health warning effectiveness measures and the Labels Impact Index indicated that the effectiveness of both the Canadian, and the U.S. warnings declined significantly over time. The Canadian warnings showed greater declines in effectiveness than the U.S. warnings, likely due to the initial novelty of the Canadian warnings. Despite the greater decline in Canada, the Canadian pictorial warnings were significantly more effective than the U.S. text-only warnings throughout the study.
  
  
  CONCLUSIONS
  Health warnings decline in effectiveness over time. Health warnings on tobacco products should be changed periodically to maintain effectiveness.
authors: Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada;
authors: Sara C
authors: SC
authors: Hitchman
authors: Pete
authors: P
authors: Driezen
authors: Christine
authors: C
authors: Logel
authors: David
authors: D
authors: Hammond
authors: Geoffrey T
authors: GT
authors: Fong
mesh_terms: D000293:Adolescent; D000328:Adult; D002170:Canada; D003625:Data Collection; D005260:Female; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011356:Product Labeling / Q000639:trends*; D012907:Smoking / Q000523:psychology; D016540:Smoking Cessation / Q000379:methods / Q000523:psychology; D000074606:Smoking Prevention; D013997:Time Factors; D062789:Tobacco Products / Q000009:adverse effects; D014481:United States; D055815:Young Adult