Evaluating the impact of health warnings in Brazil over 7 years (2009 - 2016): findings from the ITC Brazil Wave 1-3 surveys

摘要

Background: Studies demonstrate that large pictorial warnings (PHWs) on both sides of the pack have greater impact than text-only warnings. For over a decade, Brazil has had 100% pictorial warnings but only on the back of pack. In 2009, Brazil introduced dramatic fear-arousing images. In 2016, Brazil finally added a front warning although text-only and 30%. This study evaluated the 2009 and 2016 changes on key perceptual and behavioural indicators of warning impact. Methods: Data were analyzed from Waves 1-3 (2009-2016) of the International Tobacco Control (ITC) Brazil Survey, a longitudinal cohort survey of representative samples of adult smokers in Rio de Janeiro, S?o Paulo, and Porto Alegre (N=1,719). Key outcomes were 6 validated indicators of warning impact. The 2009 warning revision was implemented 2 months after Wave 1 (2009) and 3 years before Wave 2 (2012-13). The 2016 warning revision (introducing front 30% text warnings) was implemented 3 years after Wave 2 (2012-13) and 8 months before Wave 3 (2016-17). Thus, pre-post evaluations of the two revisions were conducted by testing differences in the impact indicators across the three waves. Results: Three indicators of warning effectiveness increased significantly between W1 and W2 (showing greater effectiveness of introducing dramatic fear-arousing images of the 2009 revision) and declined at W3 (showing lack of effectiveness of introducing the front text-only warning): noticing (W1=45%; W2=51%; W3=49%), reading (W1=34%; W2=41%; W3=36%), avoiding labels (W1=43%; W2=45%; W3=34%). The remaining 3 indicators (forgoing smoking, thinking about risks, and thinking about quitting) declined at W2 and W3. Conclusions: Introducing dramatic fear-arousing images (2009) increased warning effectiveness, but introducing 30% text-only front warnings (2016) did not. There was also evidence of “wearout” of warning impact. These findings demonstrate the importance of frequent warning revision, and the need for pictorial warnings on the FRONT of the pack, consistent with FCTC Article 11 Guidelines.