12A.3 Evidence about the effects of health warnings

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. Nonetheless, there has been considerable research into the potential for health warnings to promote changes in attitudes and behaviours associated with reductions in 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.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). One reason for this is that new health warnings on packs are often rolled out simultaneously with other forms of tobacco control such as taxation increases and mass media campaigns. Or as notably happened in Australia, with plain packaging policy. While it may be possible to gather evidence of effects of health warnings on smoking behaviour, quantifying their contribution to changes in smoking prevalence or tobacco consumption is much more challenging.¹ The IARC instead recommends 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.¹

The world’s first graphic health warnings were implemented in Canada in 2001. Research before this time found that text-only health warnings effectively increased awareness of tobacco-related diseases and knowledge of the constituents of tobacco and may have prompted changes in smoking behaviours.^2,3 The effectiveness of graphic health warnings has been studied since 2001 in a multitude of countries, and has been the subject of numerous comprehensive reviews.^4,5 The International Tobacco Control (ITC) Four Country Survey is a multi-country survey of people who smoke which commenced in 2002 in in Canada, the United States, the United Kingdom and Australia. Because it incorporated both cohort and repeat cross-sectional elements it was able to assess the effects of the many tobacco control policies that have been implemented in those countries over time, enabling evaluation of policies at multiple points in time within the same country, with multiple countries as control/comparison groups.⁴

This section extracts findings from the large body of research on the effects of warnings implemented over the past three decades. Most of these studies assess the effects of graphic health warnings, as opposed to the earlier text only warning. See Section 12A.4 for a discussion of what is known about features of warnings believed to maximise their effectiveness. 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.

12A.3.1 Awareness of health warnings

A major review published in 2011⁶ identified a dozen studies published to December 2010 that documented high levels of awareness for health warnings introduced on tobacco packages.^3,7-17 Studies published since 2010 continue to show that the strengthening of health warnings with pictures and increased size resulted in warnings being more frequently noticed and read.^18-24

More people who smoke reported getting information about the risks of smoking from health warnings than from any other source, except TV, in a majority of countries.^4,6 Health warnings are also a prominent source of health information for young people who do not smoke and the general public.^6,8,12-15 Non-smokers have high level of recall for specific messages on packs.^8,14,15

12A.3.2 Increase in knowledge about health effects

Knowledge of health risks is an important predictor of cessation attempts and smoking cessation, and may help prevent smoking initiation.^6,25,26 Overall, health warnings contribute to increased knowledge about health effects.^6,27,28 High awareness of concepts covered in health warnings has been reported following the introduction of warnings in Belgium²⁹ and Europe.³⁰ Awareness of smoking-related conditions covered in health warnings is higher than awareness of conditions not covered at the time by warnings.^31-33 People who smoke 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.^4,33-35 For example, in Canada, which introduced a warning about smoking and impotence in 2001, people who smoke were almost three times more likely to know about that risk than those living in the US, the UK and Australia which did not have the same warning at the time of study.³⁴ Introduction of new or strengthened warnings has been shown to lead to increased knowledge of the subject matter contained in the warnings in Canada,³⁶ Australia,^3,31,37-41 the UK,³⁴ The Netherlands,⁴² France⁴³ and Kenya.⁴⁴ For graphic health warnings developed by the US Food and Drug Administration, but not yet implemented, those related to less widely known health effects resulted in greater learning of new information.⁴⁵

12A.3.3 Increase in thoughts about quitting

Health warnings can invoke in people who smoke thoughts not just about the harms of smoking but also thoughts about quitting.^{18,21,22,41,46} Exposure to health warnings occasionally leads to forgoing cigarettes that would otherwise have been smoked.^{21,22,41,47,48} Stronger warnings stimulate more of these reactions, including fear reactions.^33,41,49 Both rotating and non-rotating warnings can stimulate an interest in quitting.⁵⁰ Negative emotions elicited by health warnings encourage behaviour change, promoting attention to warnings and behavioural responses that positively predict quit attempts.^51-55 Multiple studies have shown an increase in quit intentions occurs after rollout of graphic health warnings.⁵⁶ In one study, the perceived severity of the health condition, the perceived vulnerability, response efficacy, and health anxiety elicited by a graphic health warning were associated with intention to quit.⁵⁷

Some people who smoke also take steps to avoid stronger warnings, particularly for graphic rather than text warnings.^58-62 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 people who smoke to try to smoke less or to try to quit. One-fifth of people who smoke reported such effects after introduction of enlarged text warnings in the EU from 2001.¹⁵ In countries such as Canada and Australia, even higher percentages of people have reported warnings as having prompted quitting behaviours. More than 40% of people who smoke in one Canadian survey reported that health warnings had motivated them to quit.⁵⁸ In response to a Government-sponsored survey in 2008,⁸ 57% of Australians who smoke 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 Australians who smoke reported that the enhanced graphic health warnings introduced in 2012 made them think about quitting.⁴¹ A survey of 1500 people who smoke conducted in Pakistan in 2014²¹ reported that 32% had attempted to quit following introduction of graphic health warnings in that country. In an experimental study in the US,⁶³ adding proposed new graphic health warnings to cigarette packs also effectively increased quit attempts and success.

12A.3.5 Changes in smoking behaviour, quit attempts and preventing relapse

Changes in smoking behaviours that are positively associated with subsequent quit attempts include forgoing some cigarettes and butting out cigarettes before they are finished.⁶⁴ Research from Australia,² Canada,⁴⁷ and the ITC four-country (Australia, Canada, the US and UK) study⁶⁰ show that responses to health warnings such as noticing cigarette warnings and forgoing cigarettes predict subsequent quitting attempts among individuals who smoke. 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.⁶⁰

Some studies have found that graphic health warnings increased quit attempts by eliciting aversive reactions, reducing positive perceptions and by keeping health messages vividly in the minds of people who smoke rather than changing thoughts and beliefs.^65,66

Seeing cigarettes packs is generally predictive of greater chances of relapse. However, once this is controlled for, researchers in the ITC study have found that exposure to warning labels can remind ex-smokers of their reasons for quitting, and in this way can reduce their chances of relapsing.⁶⁷ One way in which warning labels may work to reduce consumption (and potentially, relapse) is that the feelings of disgust evoked by some warnings can help people who smoke to resist the negative effect of exposure to smoking cues on their ability to resist smoking.⁶⁸

12A.3.6 Effect on use of Quitlines

Health warnings may increase the success of quit attempts by promoting the use of smoking cessation services. Introducing graphic warnings and a Quitline number on cigarette packs 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.⁶⁹ 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.⁷⁰ And they increased again following the introduction of larger graphic warnings as part of Australia’s plain packaging of cigarette packs in 2012.⁷¹ Similarly, after the New Zealand Quitline number was featured prominently on packs, awareness, and use of the service increased.^72-74

12A.3.7 Effects of health warnings on young people

A large body of research has examined the effects of the introduction of health warnings on young people.^{8,13,14,39,75-81} These studies provide strong evidence that health warnings on tobacco packaging have influenced young people’s attitudes, intentions, and smoking behaviour.^{8,13,14,39,79,82,83}

In a national survey in the UK, 90% of youth non-smokers reported that warnings had ‘put them off smoking’.¹⁴ National representative surveys of more than 26,000 adolescents (11-16 years) 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.¹⁵ Between one-fifth and two-thirds of youth non-smokers indicated that health warnings had helped prevent them from taking up smoking in Canada¹³ and Australia⁸—see Section 12A.5.1 for further details.

In Nigeria,⁷⁹ 544 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 study⁸⁰ 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 US⁸¹ 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).

A study of school students n in South Korea found that younger students (year 7) were more likely to decide not to smoke than older (year 12) students after seeing the new graphic health warnings.⁸⁴ Non-smoking students were more likely to view smoking as dangerous compared to those who smoked, used e-cigarettes or were exposed to secondhand smoke.⁸⁴ Another study in South Korea showed that quit attempts in adolescents who smoke were higher among those who had seen graphic health warnings compared to those who had not.⁸⁵ A qualitative study of the responses to plain packaging and health warnings of young females who smoked showed that while they found the warnings shocking and offensive, they also found them to be lacking in credibility and irrelevant to their life stage.⁸⁶

12A.3.8 Effectiveness among low-income people who smoke and other priority populations

A study conducted as part of the International Tobacco Control (ITC) Policy Evaluation study examined (i) ratings of the health warnings on warning salience, thoughts of harm and quitting and forgoing of cigarettes among people who smoke; (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).⁸⁷ The impact was highest among those of low socio-economic status. A later study using data from 2002 to 2020 from the ITC study found that the 2012 rollout of new graphic health warnings in Canada was associated with stronger cognitive and behavioural responses and more quit intentions, compared to the US where no graphic health warnings were issued. This effect was particularly strong in people from low socioeconomic groups.⁸⁸ There is also evidence that the 2001 Canadian graphic health warnings had similar effects on reductions in smoking across different education levels.⁸⁹

An EU survey also found that young people and manual workers were slightly more likely to perceive health warnings as effective.¹⁵ See Section 12A.4 for discussion about benefits of graphic warnings for those with lower levels of literacy.

Preliminary evidence suggests that countries with pictorial warnings demonstrate fewer disparities in health knowledge across educational levels.⁹⁰ The findings of one important study⁹¹ 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 equity by reaching 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.⁹² 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.^34,41,59,70 For example, findings from Australia’s triennial National Drugs Strategy Household Survey has shown a steady decline in the proportion of people who smoke who report that health warnings helped motivate them to quit or cut down. In 2016, 8.5% 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 2007.⁹³ Findings of a 2018 survey on the impact of the 2012 graphic health warnings reported that 54% of Australians who smoke and recently quit took more notice of the graphic health warnings when they first came out, indicative of wear-out of these health warnings over time.⁴¹

This evidence is supported by findings of earlier research examining consequences of not rotating health warnings in Canada and the US.⁹⁴ 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 13-17.⁹⁵ 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 newly implemented, graphic health warnings 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.⁹⁶ People who smoked reported greater message fatigue than transitioning smokers (quit smoking in the past two years or currently trying to quit) and nonsmokers. Persons who were younger, male, and had higher levels of education and income reported higher levels of message fatigue than other groups. A systematic review from 2021 found that graphic health warnings wear-out despite the format of the warning (pictorial or text) and recommended changing sets of graphic health warnings at the beginning of wear-out to maximise effectiveness.⁵⁶

12A.3.10 Other effects of graphic health warnings

 Preliminary evidence suggested that text-only or graphic health warnings many dissuade people from sharing or giving cigarettes as a present in China, which is a common social practice in this country.⁹⁷ The presence of graphic health warnings likely increases pack-hiding behaviour in social settings, which may be associated with aversive reactions from observers.⁹⁸ Large graphic health warnings on cigars are more effective than smaller text-only warnings at discouraging the use of blunts (where the hollowed out cigar leaf wrapper is used to smoke cannabis).⁹⁹

12A.3.11 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.¹⁰⁰ 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.¹⁰¹ 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).¹⁰²

The effectiveness of health warning has also been undermined by promotional stickers¹⁰³ and other design features on the packs¹⁰⁴ which are visually distracting.

Several researchers have highlighted the potential of package design to undermine the impact of health warnings. This was 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.

Test your knowledge

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