There is no doubt that health warnings have fulfilled their primary objective of informing consumers about the health risks of smoking. While health warnings that clearly informed consumers about the risks of smoking without changing the behaviour of a single person could be deemed effective in these terms, there has also been considerable interest as to whether health warnings are associated with changes in attitudes and behaviours that are known to be associated with reduced levels of smoking.
In its comprehensive scientific handbook outlining appropriate methods for the evaluation of tobacco control policies, the International Agency for Research on Cancer discusses the difficulty of assessing the impacts of warnings in the context of multiple sources of influence in knowledge about health risks.1 It states 'there are serious problems in attributing changes in national-level trends to changes in health warnings, or any other individual policy measure.' p314 It recommends instead that governments implementing health warnings assess effectiveness by monitoring a variety of measures of noticeability, believability, attention to health risks, comprehension, intention to quit, use of cessation services and perceived helpfulness of warnings in quit attempts–refer Chapter 5.5.
Most of the early population researchi about the effectiveness of tobacco health warnings introduced in particular countries comes from studies of Australian warnings introduced in 1987 and 1995.2–5 Then there were evaluations of Canada's world first graphic warnings in late 2000,5–7 and then numerous studies which have assessed the effects of Australia's 2006 graphic warnings.8–16 Numerous further studies have now been published assessing the effects of warnings in a variety of other jurisdictions. A comprehensive review of evidence published in Tobacco Control in 201117 identified a total of 94 original articles published up to December 2010 on the topic of the effectiveness of health warnings describing 72 quantitative studies, 16 qualitative studies, 5 studies with both quantitative and qualitative components and 1 review article. Research articles came from Canada (n= 35), the US (n= 29), Australia (n=16), the UK (n=13), the Netherlands (n=3), France (n = 3), New Zealand (n=3), the Netherlands (n=3), Mexico (n=3), Brazil (n =2),18 Malaysia19 and China (n=1) Belgium (n=1), Norway (n=1) as well as other European countries (n= 10). Analysis of results of surveys comparing impacts of the introduction of different sorts of health warnings at different times in different countries5,8,9,20,21 ii have been particularly valuable in establishing the effectiveness of warnings and the elements and characteristics of warnings22 likely to be most effective. Since the Hammond review, further studies have been published using data from Germany,23 China,24 Germany, a study covering France the UK and the Netherlands,20 Australia13,14… and in 14 mainly developing Asian and European countries.25
Several organisations and international research groups have now summarised the findings of research on health warnings. Hammond's review17 builds on a comprehensive assessment of the impact of health warnings internationally released in May 2009 by the International Tobacco Control Policy Evaluation Project (the ITC Project)iii.27 The Sambrook Research Group summarised the evidence to 200828 in preparation for design of new health warnings in the European Union. The International Union Against Tuberculosis and Lung Disease and Tobacco-Free Union also summarised the evidence to 2009 in a technical guide29 designed for countries aiming to meet their obligations under the FCTC. This section (A12.1.3) extracts from these reviews the most important findings to date about what is known about the real-world impact of warnings where they have been implemented. Section A12.1.4 outlines what is known (from both international comparative research and focus groups studies) about features of warnings believed to maximise their effectiveness. This includes a detailed discussion of the superiority of graphic over text-based warnings and the role of fear in prompting behaviour changes and the issue of unintended consequences. The results of studies assessing the impact of graphic health warnings introduced in Australia in 2006 are described more fully in Section A12.1.5.
As identified by Hammond,17 at least a dozen studies to December 2010 have documented high levels of awareness for health warnings on tobacco packages3,7,10,18,19,30–37 Studies published since 2010 continue to show that introduction of stronger health warnings results in warnings being more frequently noticed and read.25 More smokers report getting information about the risks of smoking from health warnings than from any other source except TV in a majority of countries (Hammond17 citing the ITC Evaluation project report27.)
Hammond's review has also found that health warnings are a prominent source of health information for young non-smokers and the general public.17 citing 10,31–34 Non-smokers have high level of recall for specific messages on packs.10,33,34
Awareness of concepts covered in health warnings has been high in studies following introduction of warnings in Belgium38 and across seven European countries after 2003.39 Awareness of conditions covered in health warnings is higher than awareness of conditions not covered at the time by warnings.12,40 Smokers have greater knowledge about particular health effects in countries where those health effects are the subject of warnings than in countries where they are not.5,27,41 Introduction of new or strengthened warnings has been shown to have increased knowledge of the subject matter contained in the warnings in Canada,42 in Australia in 1987,2 19953 and 2006,11–13,16 in the UK in 20035 and in France in 2006.43
Health warnings can invoke thoughts not just about the harms of smoking but also thoughts about quitting,25 and they occasionally lead to smokers forgoing cigarettes they would otherwise have smoked.44 Stronger warnings stimulate more of these reactions, including fear reactions.23 Some smokers also take steps to avoid stronger warnings, this being more so for graphic than text warnings.8,9,21 In all cases studied, new warnings (strengthened either with increased size and/or use of graphics) have been more effective in stimulating targeted reactions than those they replaced. Some of this effect is due to novelty, but it is clear that objectively stronger messages persistently evoke greater levels of responses than weaker ones.
Population surveys conducted after the introduction of large text or graphic health warnings suggest that they have been important in assisting smokers to try to smoke less or to try to quit. One-fifth of smokers reported such effects after introduction of enlarged text warnings in the EU from 2001.34 In countries such as Canada and Australia even higher percentages of people report warnings as having helped them. More than 40% of smokers in one Canadian survey reported that health warnings had motivated them to quit smoking.21 In response to a Government-sponsored survey in 200810 57% of smokers reported that graphic health warnings had made them think about quitting and 34% reported them having helped them to try to quit.
Data from an Australian study,4 evaluation of the introduction of graphic warnings in Canada44 and analysis of data from Australia, Canada, the US and UK in the longitudinal International Tobacco Control cohort study9 show that behaviours such as noticing cigarette warnings and forgoing cigarettes predict subsequent quitting attempts among individual smokers.
The mission of the International Tobacco Control Policy Evaluation Project (ITC Project) is to measure the psychosocial and behavioural impact of key policies of the Framework Convention on Tobacco Control (FCTC) among adult smokers.26 iv Reaction to health warnings in each wave of the study (2002 to 2006) were used to predict quitting in subsequent waves, controlling for country (proxy for warning differences) and other factors.9 These analyses were replicated on four wave-to-wave transitions. Warning salience, cognitive responses (thoughts of harm and of quitting), forgoing of cigarettes and avoidance of warnings were examined among smokers from Australia, Canada, the United Kingdom and the United States as predictors of quit attempts, and of quitting success among those who tried (one month sustained abstinence), replicated across four wave-to-wave transitions. All four responses to warnings were independently predictive of quitting activity in bivariate analyses. In multivariate analyses, both forgoing cigarettes and cognitive responses to the warnings predicted prospectively making quit attempts in all replications. However, avoiding warnings did not add predictive value consistently, and there was no consistent pattern for warning salience. There were no interactions by country. Some, but not all, of the effects were mediated by quitting intentions. There were no consistent effects on quit success. This study added to the evidence that forgoing cigarettes as a result of noticing warnings and quit-related cognitive reactions to warnings are consistent prospective predictors of making quit attempts.
Introducing graphic cigarette packet warnings and the Quitline number on cigarette packets boosts demand for Quitline services with likely flow on effects to cessation.
In the Netherlands, placement of the national Quitline number on packs with text-based warnings led to a marked increase in numbers of calls.45 Calls to the Quitline in Australia also increased after introduction of improved consumer product information in 2006, which included a requirement to list the Quitline number.15 This study shows that even in a 'mature' tobacco control environment such as Australia, such an intervention has considerable positive impact on demand for a Quitline, with positive implications for quitting.
After the New Zealand Quitline number was featured prominently on packets, awareness and use of the service increased.46–48
Only a small number of studies have examined the effects of the introduction of health warnings on young people.10,11,32,33,49–52
In a national survey in the UK, 90% of youth non-smokers reported that warnings had 'put them off smoking'.33 National representative surveys of more than 26 000 respondents from 27 EU member states and Norway found that 3 out of 10 non-smokers reported that health warnings had been effective in discouraging them from smoking.34 Hammond notes17 that between one-fifth and two-thirds of youth non-smokers indicated that health warnings had helped prevent them from taking up smoking in Canada32 and Australia10–see Section A184.108.40.206 for further details.
A study conducted as part of the International Tobacco Control Policy Evaluation study examined (i) smokers' ratings of the health warnings on warning salience, thoughts of harm and quitting and forgoing of cigarettes; (ii) impact of the warnings using a Labels Impact Index (LII), with higher scores signifying greater impact; and (iii) differences on the LII by demographic characteristics and smoking behaviour among smokers exposed to strengthened text warnings introduced in France (2007), Germany (2007), the Netherlands (2008) and the UK (2006).20 The impact was highest among smokers of low socio-economic status. The EU survey also found that young people and manual workers were slightly more likely to perceive health warnings as effective.34 See Section A12.1.4 for discussion about benefits of graphic warnings for those with limited levels of literacy. Preliminary evidence suggests that countries with pictorial warnings demonstrate fewer disparities in health knowledge across educational levels.55
Australian research shows that the peak levels of response to warnings is in the period immediately after their introduction onto packs,3 perhaps even before all packs on the market have the warnings.56 There is some decline in cognitive responses as consumers become used to seeing the images on the packs; warnings appear to lose some, but not all, of their impact with time.5, 8, 15 This finding is reflected in the results of a population survey of smokers and recent ex-smokers. Among the 23% of smokers and recent ex-smokers who reported in the 2010 National Drugs Strategy Household Survey57 having attempted to quit or cut down smoking in the previous year 15.2% mentioned health warnings as being a factor motivating their behaviour. This was down from 19.4% in 2007 (shortly after introduction of the new pictorial health warnings) which in turn was higher than the 16.4% naming health warnings as a motivator in 200458 shortly before the introduction of the new warnings.
Evidence presented to a Canadian Parliamentary committee in 2010 suggested that the effectiveness of the Canadian warnings declined by 30–60% over the seven years to 2009, and that new warning labels were urgently needed to strengthen their influence in helping smokers to quit and preventing new smokers from starting to smoke.59
In 2011, British American Tobacco International released a report claiming that health warnings have had little impact on sales of tobacco products in Australia and elsewhere.60 This report included an analysis relating introduction dates for health warnings to sales of cigarettes in each country. As explained by the International Agency for Research on Cancer1 immediate changes in behaviour as would be reflected in changes in smoking prevalence or sales are an unrealistic and inappropriate indicator of the effectiveness of health warnings.
Opposition to the introduction of improved health warnings by tobacco companies–and attempts to undermine their effectiveness once introduced–suggests that tobacco industry executives believe that warnings can contribute to population changes in the consumption of tobacco products.61 Despite the requirement for warnings to be rotated with equal frequency, some researchers believe that tobacco companies may be producing a higher proportion of packs using warnings perceived to be less disturbing, with a lower proportion of packs bearing the more hard-hitting warnings. Following the introduction of seven rotating graphic health warnings in New Zealand in 2008, researchers found that tobacco packs identified in a litter-collection study were more likely to carry one of the warnings rated less disturbing (such as a pregnant women with infant or damaged lungs) in preference to the more highly disturbing warnings (such as gangrenous toes, mouth cancer and blindness).62
Several researchers have highlighted the potential of package design to undermine the impact of health warnings. This is one important rationale for calls for plain packaging of tobacco products–see Chapter 11, Section 11.10.4 for full details.
i Research on the impact in the population of actual package warnings assessed after implementation
ii These were each counted in the Hammond Review as one study, but recorded in multiple jurisdictions.
iv The evaluation framework 'utilises multiple country controls, a longitudinal design, and a pre-specified, theory-driven conceptual model to test hypotheses about the anticipated effects of specific policies.' The ITC Project consists of parallel prospective cohort surveys of representative samples of adult smokers in multiple countries, with further countries being added as the study continues. 'Collectively, the ITC surveys constitute the first-ever international cohort study of tobacco use. The conceptual model of the ITC Project draws on the psychosocial and health communication literature and assumes that tobacco control policies influence tobacco related behaviours through a causal chain of psychological events, with some variables more closely related to the policy itself (policy-specific variables) and other variables that are more downstream from the policy, which have been identified by health behaviour and social psychological theories as being important causal precursors of behaviour (psychosocial mediators).' 26
1. International Agency for Research on Cancer. Methods for evaluating tobacco control policies Handbooks of Cancer Prevention, Tobacco Control, 12. Lyon, France: International Agency for Research on Cancer, 2009. Available from: http://com.iarc.fr/en/publications/pdfs-online/prev/handbook12/index.php
2. Hill D. New cigarette-packet warnings: are they getting through? Medical Journal of Australia 1988;148(9):478–80. Available from: http://www.ncbi.nlm.nih.gov/pubmed/3362083?dopt=Abstract
3. Borland R and Hill D. Initial impact of the new Australian tobacco health warnings on knowledge and beliefs. Tobacco Control 1997;6(4):317–25. Available from: http://tc.bmjjournals.com/cgi/content/abstract/6/4/317
4. Borland R. Tobacco health warnings and smoking-related cognitions and behaviours. Addiction 1997;92(11):1427–35. Available from: http://www3.interscience.wiley.com/journal/120194864/abstract
5. Hammond D, Fong GT, McNeill A, Borland R and Cummings KM. Effectiveness of cigarette warning labels in informing smokers about the risks of smoking: findings from the International Tobacco Control (ITC) Four Country Survey. Tobacco Control 2006;15(suppl. 3):iii19–25. Available from: http://tc.bmjjournals.com/cgi/content/abstract/15/suppl_3/iii19
6. Martens D. Graphic tobacco warnings having desired effect. Canadian Medical Association Journal 2002;166(11):1453. Available from: http://www.cmaj.ca/cgi/content/full/166/11/1453
7. Hammond D, Fong GT, McDonald PW, Cameron R and Brown KS. Impact of the graphic Canadian warning labels on adult smoking behaviour. Tobacco Control 2003;12(4):391–5. Available from: http://tc.bmjjournals.com/cgi/content/abstract/12/4/391
8. Borland R, Wilson N, Fong GT, Hammond D, Cummings KM, Yong HH, et al. Impact of graphic and text warnings on cigarette packs: findings from four countries over five years. Tobacco Control 2009;18(5):358-64. Available from: http://tobaccocontrol.bmj.com/cgi/content/abstract/18/5/358
9. Borland R, Yong H, Wilson N, Fong G, Hammond D, Cummings K, et al. How reactions to cigarette packet health warnings influence quitting: findings from the ITC Four-Country survey. Addiction 2009;104(4):669-75. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19215595
10. Shanahan P and Elliott D. Evaluation of the Effectiveness of the Graphic Health Warnings on Tobacco Product Packaging 2008. Canberra: Department of Health and Ageing, 2009. Available from: http://www.health.gov.au/internet/main/publishing.nsf/Content/F22B9115FD392DA5CA257588007DA955/$File/hw-eval-full-report.pdf
11. White V, Webster B and Wakefield M. Do graphic health warning labels have an impact on adolescents' smoking-related beliefs and behaviours? Addiction 2008;103(9):1562–71. Available from: http://www.ncbi.nlm.nih.gov/pubmed/18783508
12. McCarthy M, Germain D, Brennan E and Durkin S. Perceptions about the health effects of smoking and passive smoking among Victorian adults, 2003–2007. CBRC Research Paper Series no. 37 Melbourne: Centre for Behavioural Research in Cancer, The Cancer Council Victoria, August, 2007. Available from: http://www.cancervic.org.au/perceptions_smoking_cbrc_09.html
13. Brennan E, Durkin SJ, Cotter T, Harper T and Wakefield MA. Mass media campaigns designed to support new pictorial health warnings on cigarette packets: evidence of a complementary relationship. Tobacco Control 2011;20(6):412-18. Available from: http://tobaccocontrol.bmj.com/content/early/2011/04/07/tc.2010.039321.abstract
14. Miller C, Hill D, Quester P and Hiller J. Response of mass media, tobacco industry and smokers to the introduction of graphic cigarette pack warnings in Australia. European Journal of Public Health 2009;19(6):644-9. Available from: http://eurpub.oxfordjournals.org/cgi/content/abstract/ckp089v1
15. Miller C, Hill D, Quester P and Hiller J. Impact on the Australian Quitline of new graphic cigarette pack warnings including the Quitline number. Tobacco Control 2009;18(3):235-7. Available from: http://tobaccocontrol.bmj.com/content/18/3/235.full
16. Miller C, Quester P, Hill D and Hiller J. Smokers' recall of Australian graphic cigarette packet warnings and awareness of associated health effects, 2005-2008. BMC Public Health 2011;11(1):238. Available from: http://www.biomedcentral.com/content/pdf/1471-2458-11-238.pdf
17. Hammond D. Health warning messages on tobacco products: a review. Tobacco Control 2011;on line first Available from: http://tobaccocontrol.bmj.com/content/early/2011/05/23/tc.2010.037630.abstract
18. Cavalcante T. Labelling and packaging in Brazil. National Cancer Institute, Health Ministry of Brazil; World Health Organization, 2010. Available from: http://www.who.int/tobacco/training/success_stories/en/best_practices_brazil_labelling.pdf
19. Fathelrahman A, Omar M, Awang R, Borland R, Fong G, Hammond D, et al. Smokers' responses toward cigarette pack warning labels in predicting quit intention, stage of change, and self-efficacy. Nicotine & Tobacco Research 2009;11(3):248-53. Available from: http://ntr.oxfordjournals.org/content/early/2009/01/01/ntr.ntn029.abstract
20. Hitchman S, Mons U, Nagelhout G, Guignard R, McNeill A, Willemsen M, et al. Effectiveness of the European Union text-only cigarette health warnings: findings from four countries. European Journal of Public Health 2011;[Epub ahead of print] Available from: http://eurpub.oxfordjournals.org/content/early/2011/09/14/eurpub.ckr099.long
21. Hammond D, Fong G, Borland R, Cummings KM, McNeill A and Driezen P. Text and graphic warnings on cigarette packages: findings from the international tobacco control four country study. American Journal of Preventive Medicine 2007;32(3):202–9. Available from: http://www.ncbi.nlm.nih.gov/pubmed/17296472
22. Fong GT, Hammond D and Hitchman SC. The impact of pictures on the effectiveness of tobacco warnings. Bulletin of the World Health Organization 2009;87(8):640–3. Available from: http://www.who.int/bulletin/volumes/87/8/09-069575/en/index.html
23. Schneider S, Gadinger M and Fischer A. Does the effect go up in smoke? A randomized controlled trial of pictorial warnings on cigarette packaging. Patient Education and Counseling 2011;[Epub ahead of print] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21482060
24. Qin Y, Wu M, Pan X, Xiang Q, Huang J, Gu Z, et al. Reactions of Chinese adults to warning labels on cigarette packages: a survey in Jiangsu Province. BMC Public Health 2011;11:133. Available from: http://www.biomedcentral.com/content/pdf/1471-2458-11-133.pdf
25. Caixeta RB, Blanco A, Fouad H, Khoury RN, Sinha DN, Rarick J, et al. Cigarette package health warnings and interest in quitting smoking--- 14 countries, 2008--2010. Morbidity and Mortality Weekly Report (MMWR) 2011;60(20):645–51. Available from: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6020a2.htm
26. Fong GT, Cummings KM, Borland R, Hastings G, Hyland A, Giovino GA, et al. The conceptual framework of the International Tobacco Control (ITC) Policy Evaluation Project. Tobacco Control 2006;15(suppl. 3):iii3-11. Available from: http://tc.bmjjournals.com/cgi/content/abstract/15/suppl_3/iii3
27. International Tobacco Control Policy Evaluation Project. FCTC Article 11 Tobacco warning labels: evidence and recommendations from the ITC Project. Buffalo, New York: Roswell Park Cancer Institute, 2009. Available from: http://roswelltturc.org/ITCwarningreport.pdf
28. Sambrook Research International. A review of the science base to support the development of health warnings for tobacco packages. A report prepared for European Commission, Directorate General for Health and Consumers. Brussels: European Commission, 2009. Available from: http://ec.europa.eu/health/tobacco/docs/warnings_report_en.pdf
29. Selin H. Tobacco packaging and labelling: technical guide. International Union Against Tuberculosis and Lung Disease and Tobacco-Free Union, 2010. Available from: http://www.tobaccofreeunion.org/files/186.pdf
30. Elliott and Shanahan Research. Evaluation of the health warnings and explanatory health messages on tobacco products. Canberra: Tobacco and Alcohol Strategies Section, Department of Health and Aged Care, 2000. Available from: http://www.health.gov.au/internet/main/publishing.nsf/content/4FA9E17EB0A1FB6ECA25776900054914/$File/warneval.pdf
31. Chaiton M, Cohen J, Kaiserman MJ and Leatherdale ST. Ch 7. Beliefs and attitudes. Youth Smoking Survey-Technical Report. Health Canada, 2002. Ottawa: Health Canada, 2005. Available from: http://www.hc-sc.gc.ca/hc-ps/pubs/tobac-tabac/yss-etj-2002/index-eng.php
32. Environics Research Group Ltd. The health effects of tobacco and health warning messages on cigarette packages: survey of youth: wave12 surveys. Ottawa: Health Canada, 2007. Available from: http://www.hc-sc.gc.ca/hc-ps/tobac-tabac/research-recherche/por-rop/label-etiquet-eng.php
33. Moodie C, Mackintosh A and Hammond D. Adolescents' response to text-only tobacco health warnings: results from the 2008 UK Youth Tobacco Policy Survey. European Journal of Public Health 2009;20(4):463-9. Available from: http://eurpub.oxfordjournals.org/cgi/content/full/ckp199v1
34. European Commission. Eurobarometer: survey on tobacco (analytical report). 2009. Available from: http://ec.europa.eu/public_opinion/flash/fl_253_en.pdf
35. Environics Research Group Ltd. Health warnings testing: final report. Ottawa: Prepared for Health Canada, 1999. Available from: http://legacy.library.ucsf.edu/tid/nql70g00
36. Les E´tudes De Marche Createc. Quantitative study of Canadian youth smokers and vulnerable non-smokers: effects of modified packaging through increasing the size of warnings on cigarette packages. Prepared for Health Canada. Ottawa: Health Canada, 2008. Available from: http://www.tobaccolabels.ca/healt/canada2008w3
37. Les E´tudes De Marche Createc. Quantitative study of Canadian adult smokers and vulnerable non-smokers: effects of modified packaging through increasing the size of warnings on cigarette packages. Prepared for Health Canada. Ottawa: Health Canada, 2008. Available from: http://epe.lac-bac.gc.ca/100/200/301/pwgsc-tpsgc/por-ef/health/2008/254-07a-e/report.pdf
39. Devlin E, Anderson S, Hastings G and MacFadyen L. Targeting smokers via tobacco product labelling: opportunities and challenges for Pan European health promotion. Health Promotion International 2005;20(1):41-9. Available from: http://heapro.oxfordjournals.org/content/20/1/41.full.pdf+html
40. Ng D, Roxburgh S, Sanjay S and Au Eong K. Awareness of smoking risks and attitudes towards graphic health warning labels on cigarette packs: a cross-cultural study of two populations in Singapore and Scotland. Eye 2009;24(5):864-8. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19696800?dopt=Citation
41. Thrasher J, Hammond D, Fong G and Arillo-Santillán E. Smokers' reactions to cigarette package warnings with graphic imagery and with only text: a comparison between Mexico and Canada. Salud pública de México 2007;49(suppl. 2):S233-40.
42. Environics Research Group Ltd. The health effects of tobacco and health warning messages on cigarette packages: survey of adults and adult smokers: Wave 9 surveys. Ottawa: Health Canada, 2005. Available from: http://www.smoke-free.ca/warnings/WarningsResearch/POR-04-19%20Final%20Report%205552%20Adult%20wave%209.pdf
43. Fong G, Ratte S and Craig L ea. E´valuation des politiques de lutte contre le tabagisme en France: re´sultats de la premie`re vague de l'enqueˆte ITC France. Evaluating tobacco control policies in France: Results of the first wave of the ITC France Survey. Bulletin E´pide´miologique Hebdomadaire (Nume´ro the´matiquedJourne´e mondiale sans tabac 2008. (Special IssuedWorld No Tobacco Day 2008). Weekly Epidemiological Bulletin 2007;22:183-7. Available from: http://www.invs.sante.fr/beh/
44. Hammond D, Fong G, McDonald P, Brown K and Cameron R. Graphic Canadian cigarette warning labels and adverse outcomes: evidence from Canadian smokers. American Journal of Public Health 2004;94(8):1442–5. Available from: http://www.ajph.org/cgi/content/full/94/8/1442
45. Willemsen MC, Simons C and Zeeman G. Impact of the new EU health warnings on the Dutch quit line. Tobacco Control 2002;11(4):381–2. Available from: http://tobaccocontrol.bmj.com/cgi/content/full/11/4/381
46. Wilson N, Weerasekera D, Hoek J, Li J and Edwards R. Increased smoker recognition of a national quitline number following introduction of improved pack warnings: ITC Project New Zealand. Nicotine & Tobacco Research 2010;12(suppl.):S72–7. Available from: http://ntr.oxfordjournals.org/content/12/suppl_1/S72.long
47. Li J and Grigg M. New Zealand: new graphic warnings encourage registrations with the quitline. Tobacco Control 2009;18(1):72. Available from: http://tobaccocontrol.bmj.com/content/18/1/72.full?sid=1283a803-1cbe-4db3-9956-ee41b10ae647
48. Wilson N, Li J, Hoek J, Edwards R and Peace J. Long-term benefit of increasing the prominence of a quitline number on cigarette packaging: 3 years of Quitline call data. New Zealand Medical Journal 2010;123(1321):109-11. Available from: Wilson N, Li J, Hoek J, Edwards R, Peace J.
49. Robinson T and Killen J. Do cigarette warning labels reduce smoking? Paradoxical effects among adolescents. Archives of Pediatrics & Adolescent Medicine 1997;151(3):267-72. Available from: http://www.ncbi.nlm.nih.gov/pubmed/9080935
50. Ho R. Cigarette advertising and cigarette health warnings: what role do adolescents' motives for smoking play in their assessment? Australian Psychologist 1994;29(1):49-56. Available from: http://onlinelibrary.wiley.com/doi/10.1080/00050069408257321/abstract
51. O'Hegarty M, Pedersen L, Nelson D, Mowery P, Gable J and Wortley M. Reactions of young adult smokers to warning labels on cigarette packages. American Journal of Preventative Medicine 2006;30(6):467–73. Available from: http://www.ncbi.nlm.nih.gov/pubmed/16704939
52. Peterson E, Thomsen S, Lindsay G and John K. Adolescents' attention to traditional and graphic tobacco warning labels: an eye-tracking approach. Journal of Drug Education 2010;40(3):227–44. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21313984
53. Goodall C and Appiah O. Adolescents' perceptions of Canadian cigarette package warning labels: investigating the effects of message framing. Health Communication 2008;23(2):117–27. Available from: http://www.informaworld.com/smpp/content?content=10.1080/10410230801967825
54. Sabbane LI, Lowrey TM and Chebat J-C. The effectiveness of cigarette warning label threats on nonsmoking adolescents. Journal of Consumer Affairs 2009;43(2):332–45. Available from: http://onlinelibrary.wiley.com/doi/10.1111/j.1745-6606.2009.01142.x/abstract
55. Siahpush M, McNeill A, Hammond D and Fong GT. Socioeconomic and country variations in knowledge of health risks of tobacco smoking and toxic constituents of smoke: results from the 2002 International Tobacco Control (ITC) Four Country Survey. Tobacco Control 2006;15(suppl. 3):iii65-70. Available from: http://tobaccocontrol.bmj.com/content/15/suppl_3/iii65.abstract
56. Trotter L. Tobacco health warnings: longitudinal evaluation effects on recall and smoking related behaviours. Quit Evaluation Studies no. 9. The Anti-Cancer Council of Victoria, 1998 133-42. Available from: http://www.quit.org.au/downloads/QE/QE9/QE9Home.html
57. Australian Institute of Health and Welfare. 2010 National Drug Strategy Household Survey: survey report. Drug statistics series no. 25, AIHW cat. no. PHE 145. Canberra: AIHW, 2011. Available from: http://www.aihw.gov.au/publication-detail/?id=32212254712&libID=32212254712&tab=2
58. Australian Institute of Health and Welfare. 2004 National Drug Strategy Household Survey: detailed findings. Drug strategy series no.16, AIHW cat. no. PHE 66. Canberra: AIHW, 2005. Available from: http://www.aihw.gov.au/publications/phe/ndshsdf04/ndshsdf04.pdf
59. McEwen K. ITC evidence of Canadian warning label wear-out presented to policymakers. International Tobacco Control Policy Evaluation Project, December, 2010 [viewed 25 March 2009] . Available from: http://www.itcproject.org/blogs/mediacover/itcevidenceofcanadianwarninglabelwearoutpresentedt
60. Deloitte. Tobacco packaging regulation: An international assessment of the intended and unintended consequences. London: 2011. Available from: http://www.bat.com/group/sites/uk__3mnfen.nsf/vwPagesWebLive/DO8GHFEN/$FILE/medMD8GHFFW.pdf?openelement
61. Chapman S and Carter SM. 'Avoid health warnings on all tobacco products for just as long as we can': a history of Australian tobacco industry efforts to avoid, delay and dilute health warnings on cigarettes. Tobacco Control 2003;12(suppl. 3):iii13–22. Available from: http://tc.bmjjournals.com/cgi/content/abstract/12/suppl_3/iii13
62. Wilson N. Smokers respond to pictorial health warnings. Science 2011;333(6044):822. Available from: http://www.sciencemag.org/content/333/6044/822.1.short
63. Mir H, Buchanan D, Gilmore A, McKee M, Yusuf S and Chow C. Cigarette pack labelling in 12 countries at different levels of economic development. Journal of Public Health Policy 2011;32(2):146-64. Available from: http://www.palgrave-journals.com/jphp/journal/vaop/ncurrent/full/jphp20113a.html
Cameron, L.D., J.K. Pepper, and N.T. Brewer, Responses of young adults to graphic warning labels for cigarette packages. Tobacco Control, 2013.Available from: http://tobaccocontrol.bmj.com/content/early/2013/04/25/tobaccocontrol-2012-050645.abstract
Thomson, G., Wilson, N., and Maubach, N., Switch to large pictorial health
warnings on cigarette packs. BMJ, 2013. 346:
p. f2084. Available from: http://www.bmj.com/content/346/bmj.f2084.pdf%2Bhtml
University of Granada, Warning images for cigarette packs do not make a strong enough emotional impact, in MedicalXPress 2013.Available from: http://medicalxpress.com/news/2013-05-images-cigarette-strong-emotional-impact.html
Partos, Ron Borland, Hua-H Yong, James Thrasher, David Hammond.
packet warning labels can prevent relapse: findings from the International
Tobacco Control 4-Country policy evaluation cohort study. Tob Control
James F Thrasher, Nandita Murukutla, Rosaura Perez-Hernandez, Jorge Alday, Edna Arillo-Santillan, Claudia Cedillo, Juan Pablo Gutierrez. Linking mass media campaigns to pictorial warning labels on cigarette packages: a cross-sectional study to evaluate effects among Mexican smokers. Tob Control 2013;22 e57-e65 http://tobaccocontrol.bmj.com/cgi/content/abstract/22/e1/e51?etoc