There is no doubt that health warnings have fulfilled their primary objective of informing consumers about the health risks of smoking. Health warnings that clearly inform consumers about the risks of smoking, even without changing the behaviour of a single person, are deemed effective in these terms. There has been considerable interest as to whether health warnings are also associated with changes in attitudes and behaviours associated with reduced levels of smoking.
The International Agency for Research on Cancer (IARC) discusses the difficulty of assessing the impact of health warnings in its comprehensive scientific handbook outlining appropriate methods for the evaluation of tobacco control policies. It emphasises the particular challenges with assessing the effectiveness of warnings in the context of multiple sources of influence in knowledge about health risks.1 According to the IARC, ‘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 the following measures: 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 of the handbook.
Most of the early population research about the effectiveness of tobacco health warnings comes from studies of Australian warnings introduced in 1987 and 1995.2-5 These studies were followed by evaluations of the world’s first graphic warnings implemented in Canada in 2001,5-7 as well as studies which assessed the effects of Australia’s 2006 graphic warnings.8-16 Numerous studies have now been published assessing the effects of warnings in a variety of other countries. A comprehensive review of evidence published in Tobacco Control in 201117 identified 94 original articles on the topic of the effectiveness of health warnings, from countries including Canada, the US, Australia, the UK, the Netherlands, France, New Zealand, the Netherlands, Mexico, Brazil, Malaysia, China, Belgium, and Norway. Surveys comparing impacts of the introduction of different types of health warnings at different times in different countries 5, 8, 9, 18, 19 have been particularly valuable in establishing the effectiveness of warnings and the elements and characteristics of warnings20 likely to be most effective.
Several organisations and international research groups summarised the findings of this early research on health warnings including the comprehensive assessment of the impact of health warnings released by the International Tobacco Control Policy Evaluation Project (the ITC project) in 2009,21 the Sambrook Research Group summary of the evidence up to 2008,22 and the International Union Against Tuberculosis and Lung Disease and Tobacco Free Union summary of the evidence up to 2009.23
The evidence of the effectiveness of these warnings continues to grow. Since the Hammond review, a quantitative systematic review of evidence published on the effectiveness of strengthened health warnings on cigarette packs identified 32 studies published up to 2014, from 20 countries.24 Additional studies have been published from various countries including Germany,25 China,26 Australia,13, 14, 27, 28 the US,29-35 Canada,28, 35-37 Pakistan,38 Nigeria,39 Lebanon,40, 41 Uruguay,42 France, the UK and the Netherlands,18 Mexico,28 and developing Asian and European countries.43
This section extracts from the findings of this growing body of research to discuss what is known about the effectiveness of warnings where they have been implemented. Section 12A.4 outlines what is known 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 health warnings introduced in Australia in 2006 and 2012 are described more fully in Section 12A.5 and in Section 11A.9.
12A.3.1 Awareness of health warnings
As identified by Hammond,17 at least a dozen studies to December 2010 documented high levels of awareness for health warnings on tobacco packages.3, 7, 10, 44-52 Studies published since 2010 continue to show that introduction of stronger health warnings results in warnings being more frequently noticed and read.38, 42, 43, 53, 54
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.17, 21 Health warnings are also a prominent source of health information for young non-smokers and the general public.10, 17, 47-50 Non-smokers have high level of recall for specific messages on packs.10, 49, 50
12A.3.2 Increase in knowledge about health effects
Overall, health warnings contribute to increased knowledge about health effects.55 High awareness of concepts covered in health warnings has been reported following introduction of warnings in Belgium56 and Europe.57 Awareness of smoking-related conditions covered in health warnings is higher than awareness of conditions not covered at the time by warnings.12, 37, 58 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, 21, 37, 59 Introduction of new or strengthened warnings has been shown to lead to increased knowledge of the subject matter contained in the warnings in Canada,60 in Australia,2, 3, 11-13, 16, 27 in the UK,5 and in France.61
12A.3.3 Increase in thoughts about quitting
Health warnings can invoke thoughts not just about the harms of smoking but also thoughts about quitting,27, 38, 42, 43, 62 and they occasionally lead to smokers forgoing cigarettes they would otherwise have smoked.27, 30, 38, 42, 63 Stronger warnings stimulate more of these reactions, including fear reactions.25, 27, 37 Negative emotions elicited by health warnings encourage behaviour change, promoting attention to warnings and behavioural responses that positively predict quit attempts.32, 34, 64-66
Some smokers also take steps to avoid stronger warnings, particularly for graphic rather than text warnings.8, 9, 19, 33, 67 Research shows that 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.
12A.3.4 Self-reported usefulness in quitting
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 2001.50 In countries such as Canada and Australia, even higher percentages of people report warnings as having prompted quitting behaviours. More than 40% of smokers in one Canadian survey reported that health warnings had motivated them to quit smoking.19 In response to a Government-sponsored survey in 2008,10 57% of Australian smokers reported that graphic health warnings (which started appearing on packs in Australia in mid-2006) had made them think about quitting and 34% reported them having helped them to try to quit. In a similar survey conducted in 2018, 52% of Australian smokers reported that the enhanced graphic health warnings introduced in 2012 made them think about quitting.27 A survey of 1500 smokers conducted in Pakistan in 201438 reported 32% of smokers attempted to quit following introduction of graphic health warnings in that country. In one study in the US,31 adding graphic health warnings to cigarette packs effectively increased quit attempts and success.
12A.3.5 Documented quit attempts
Research from Australia,4 Canada,63 and the ITC four-country (Australia, Canada, the US and UK) study9 show that responses to health warnings such as noticing cigarette warnings and forgoing cigarettes predict subsequent quitting attempts among individual smokers. The ITC study found strong evidence that health warnings stimulate such reactions that are predictable antecedents of quitting attempts. It concluded that the stronger the warnings, the greater the reactions, and thus the greater the quitting activity they evoke.9
12A.3.6 Effect on use of Quitlines
Introducing graphic cigarette packet warnings and a 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.68 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 And they increased again following the introduction of larger graphic warnings as part Australia’s plain packaging of cigarette packs in 2012.69 Similarly, after the New Zealand Quitline number was featured prominently on packets, awareness, and use of the service increased. 70-72
12A.3.7 Effects of health warnings on young people
A growing body of research has examined the effects of the introduction of health warnings on young people.10, 11, 39, 40, 48, 49, 73-77 These studies provide good evidence that health warnings on tobacco packaging have influenced young people’s attitudes, intentions, and smoking behaviour.10, 11, 39, 48, 49, 78, 79
In a national survey in the UK, 90% of youth non-smokers reported that warnings had ‘put them off smoking’.49 National representative surveys of more than 26,000 respondents from 27 EU member states and Norway found that three out of ten non-smokers reported that health warnings had been effective in discouraging them from smoking.50 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 Canada48 and Australia10—see Section 12A.5.1 for further details.
In Nigeria,39 544 students were interviewed on their perceptions of graphic warnings. The majority of students reacted to the images with fear and indicated that they believed that the images would prevent people from initiating smoking. One study 40 involving school and university students in Lebanon reported that graphic warnings positively impacted both students’ intentions not to start smoking, and intentions to quit. In the US 77 health warnings have also been found to lower adolescents’ intention to smoke in the future among those with a moderate lifetime smoking history (between 1 and 100 cigarettes) and increased intention to quit smoking among those with a heavy lifetime smoking history (more than 100 cigarettes).
12A.3.8 Effectiveness among low-income smokers and other sub-populations
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; and (iii) differences 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).18 The impact was highest among smokers of low socio-economic status. An EU survey also found that young people and manual workers were slightly more likely to perceive health warnings as effective.50 See Section 12A.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.80 The findings of one important study 36 in Canada provides evidence that warning labels can improve treatment reach and reach equity within vulnerable populations. It assessed the impact of the introduction of warning labels with a quit line number, on selected vulnerable sub-populations. Treatment reach for the six-month period significantly improved compared to the same six-month period the year before. Warning labels improved reach equity for young males and those with an education level of high school or less.
12A.3.9 Evidence of wear-out of health warnings
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.81 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, 27 For example, findings from Australia’s triennial National Drugs Strategy Household Survey has shown a steady decline in the proportion of smokers who report that health warnings helped motivate them to quit or cut down. In 2016, 8.5% of smokers mentioned health warnings as being a factor motivating their attempt to change their smoking behaviour, down from 11.1% in 2013, 15.2% in 2010, and 19.4% in 2007.82 Findings of a 2018 survey on the impact of the 2012 graphic health warnings reported that 54% of Australian smokers and recent quitters took more notice of the graphic health warnings when they first came out, indicative of wear out of these health warnings over time.27
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.83
This evidence is supported by findings of a study published on the consequences of not rotating health warnings in Canada and the US.35 The study analysed the wear out of health warnings in (i) the US over a period of nine years (2002–2011) where the same set of four small text warnings on the side of the pack have been in place since 1984, and (ii) Canada, where the same set of 16 pictorial warnings covered 50% of the pack from 2001 to 2012. There was significant wear out in both countries over the nine-year study period. Wear out was greater in Canada than in the US possibly because of the drop in the novelty effect of the Canadian warnings. The Canadian warnings had been introduced just prior to the study whereas the health warnings in the US had already been in place for 17 years at the start of the study period.
Another study analysed wear out of health warning labels among Australian adolescents aged 13-17.84 The study used surveys conducted over four time periods: (i) prior to health warning introduction (2005) (ii) after six months (2006), (iii) two years (2008) and five years (2011) post- health warning introduction. While cognitive responses to graphic health warnings in 2006 and 2008 increased from 2005, by 2011 cognitive responses had declined and returned to 2005 levels. These findings suggest that when novel, graphic health warning labels on cigarette packs increase cognitive responses among adolescents. However, this effect diminishes after five years, suggesting more regular message refreshment is needed.
Wear out could be influenced by the characteristics of the audience. Findings of a 2018 study on the predictors of health warnings message wear out in the US found that the level of message wear out differed across different audience segments.29 Current smokers reported greater message fatigue than transitioning smokers and nonsmokers. Persons who were younger, male, and had higher levels of education and income reported higher levels of message fatigue than other groups.
12A.3.10 Industry attempts to undermine the effectiveness of health warnings
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.85 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.86 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).87
The effectiveness of health warning has also been undermined by promotional stickers88 and other design features on the packs89 which are visually distracting.
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 InDepth 11A Packaging as promotion: Evidence for and effects of plain packaging for full details.
Relevant news and research
For recent news items and research on this topic, click here. (Last updated July 2019)
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Report of efficacy of new warnings proposed for EU
Timea Reka Partos, Ron Borland, Hua-H Yong, James Thrasher, David Hammond. Cigarette packet warning labels can prevent relapse: findings from the International Tobacco Control 4-Country policy evaluation cohort study. Tob Control 2013; 22 e43-e50
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