Table 3.
Study characteristics
| No. | Author(s), publication year | Location | Product | Study design | Sample size | Key findings |
|---|---|---|---|---|---|---|
| 1 | Anshari et al., 2018 | Australia, Canada, Mexico | Cigarette packs | Longitudinal | AU: 1671 | Over time, pictorial GHWs responses significantly changed in terms of increased noticing pictorial GHWs in Canada and Mexico, increased negative affect in Australia and decreased negative affect in Mexico. |
| CA: 2357 | ||||||
| MX: 2537 | ||||||
| 2 | Borland et al., 2009 | Australia, Canada, UK, US | Cigarette packs | Longitudinal | AU: 4111 | AU: all four indicators of impact increased following the introduction of GHW. Findings show partial wear-out of both graphic and text-only warnings, but the Canadian warnings have more sustained effects than UK ones. |
| UK: 4273 | ||||||
| CA: 4305 | ||||||
| 3 | Brewer et al., 2016 | US | Cigarette packs | RCT | 1071 | Smokers who had pictorial GHWs were more likely than those with text-only GHWs to attempt to quit smoking during trial. Pictorial GHWs increased forgoing, intentions to quit, negative emotional reactions, thinking about the harms, and conversations about quitting. |
| 4 | Brewer et al., 2019 | US | Cigarette packs | RCT | 2149 | Pictorial GHWs increased attention to, reactions to, and social interactions about warnings. However, pictorial GHWs changed almost no belief or attitude measures. Mediators of the impact of pictorial GHWs included harms of smoking and intentions to quit. |
| 5 | Cho et al., 2018 | Australia, Canada, Mexico, US | Cigarette packs | Longitudinal | AU: 1036 | Perceived risks significantly increased over time (AU & CA), where new more prominent GHWs included diseases that had not been described on prior GHWs. In MX, where pictures were changed but the diseases they described did not, perceived risks also increased. |
| CA: 1190 | ||||||
| MX: 1166 | ||||||
| 6 | Durkin et al., 2015 | Australia | Cigarette packs and roll-your-own (RYO) packs | Longitudinal | N (weighted) = 5441 | Plain Packaging (PP) early transition respondents showed significantly greater increases in stopping themselves from smoking and quit attempts. PP late transition respondents showed greater increases in intentions to quit and pack concealment. PP first year respondents showed higher levels of pack concealment, more premature stubbing and higher quit attempts. |
| 7 | Elton-Marshall et al., 2015 | China, Malaysia | Cigarette packs | Longitudinal | 2883 | Significant changes prior to the new GHW introduction in noticing and reading GHWs. Compared to Malaysia, text-only GHWs in China led to a significant change in only two of six key indicators of GHW effectiveness: forgoing and reading the GHWs. The change to pictorial GHWs in Malaysia led to significant increases in five of six indicators (noticing, reading, forgoing, avoiding, thinking about quitting). |
| 8 | Fathelrahman et al., 2010 | Malaysia | Cigarette packs | RCT | 70 | Exposure to pictorial GHWs increased awareness of risks, behavioral response and quitting intention. Interest in quitting increased significantly more in those exposed to pictorial GHWs. |
| 9 | Fathelrahman et al., 2013 | Malaysia, Thailand | Cigarette packs | Longitudinal | Pre GHW: 1018 | Multivariate predictors of “interest in quitting” were comparable across countries, but predictors of quit attempts varied. In both countries, cognitive reactions, forgoing and baseline knowledge were positively associated with interest in quitting at that wave. Thailand only: cognitive reactions, forgoing a cigarette” and interest in quitting were positively associated with quit attempts over the following inter-wave interval. |
| Post GHW: 803 | ||||||
| 10 | Glock & Kneer, 2009 | Germany | Cigarette packs | RCT | 60 | There was no major effect from the intervention condition, and after being confronted with warning labels, smokers decreased their perceived smoking-related risk. |
| 11 | Gravely et al., 2016a | Uruguay | Cigarette packs | Longitudinal | Wave 2: 1294 | All indicators of GHW effectiveness increased significantly, including salience, thinking about risks, thinking about quitting, avoiding looking, and stopping from having a cigarette ‘many times’. |
| Wave 3: 452 | ||||||
| 12 | Gravely et al., 2016b | India | Smokeless tobacco | Longitudinal | Scorpion GHW: 5991 | GHW label change in India from symbolic (scorpion) to pictorial GHWs did not result in significant increases on any of the GHW outcome indicators. |
| New pictorial GHW: 4634 | ||||||
| 13 | Green et al., 2014 | Mauritius | Cigarette packs | Longitudinal | Pre (w1): 598 | All indicators of warning effectiveness (salience, cognitive, and behavioral reactions) and the Label Impact Index (weighted combination of 4 indicators) increased significantly between Waves 1 and 2. However, between Waves 2 and 3, there was a significant decline in the proportion of smokers who reported “avoiding looking” at labels. |
| Post 12 months (w2): 555 | ||||||
| 14 | Green et al., 2019 | Canada | Cigarette packs | Longitudinal | 5863 | Adding messages to GHWs significantly increased awareness that smoking causes blindness and bladder cancer. Adding the warning that nicotine causes addiction did not significantly impact smokers’ awareness. Removing messages was shown to decrease awareness that cigarette smoke contains carbon monoxide and smoking causes impotence. |
| 15 | Hall et al., 2018 | US | Cigarette packs | RCT | 1071 | Pictorial GHWs increased negative affect, message reactance and quit intentions, but not perceived risk. Negative affect mediated the impact of pictorial warnings on quit intentions. |
| 16 | Hitchman et al., 2014 | Canada, US | Cigarette packs | Longitudinal | CA: 5309 | The effectiveness of both pictorial GHWs (CA) and text-only GHWs (US) warnings declined significantly over time. Pictorial GHWs showed greater declines in effectiveness than the text-only warnings. Despite the greater decline in pictorial GHWs, they were significantly more effective than the text-only GHWs throughout the study. |
| 17 | Kasza et al., 2017 | Australia, Canada, UK, US | Cigarette packs | Longitudinal | CA: 4884 | Between 2002 and 2015, smokers’ concern for personal health was the most frequently endorsed reason for thinking about quitting in the UK, Canada, the US and Australia, and across all reasons to quit smoking, concern for personal health had the strongest association with making a quit attempt at follow-up wave. |
| AU: 4482 | ||||||
| 18 | Kennedy et al., 2012 | Australia, Canada, UK, US | Cigarette packs | Longitudinal | AU: 3151 | After the introduction of the blindness warning, Australian smokers were more likely than before the blindness warning to report that they know that smoking causes blindness. In Australia, smokers aged over 55 years were less likely than those aged 18 to 24 to report that smoking causes blindness. |
| 19 | Li et al., 2015 | Australia, Canada, UK | Cigarette packs | Cohort | AU (t1): 1801 | The impact of warnings declined over time in all three countries. Having two rotating sets of warnings does not appear to reduce wear-out over a single set of warnings. Warning size may be more important than warning type in preventing wear-out, although both probably contribute interactively. |
| AU (t2): 1104 | ||||||
| 20 | Li et al., 2016 | Malaysia, Thailand | Cigarette packs and RYO packs | Longitudinal | TH (w3): 2465 | The main outcome was subsequent quit attempts. Following the implementation of GHWLs in Malaysia, reactions increased, in some cases to levels similar to the larger Thai warnings, but declined over time. In Thailand, reactions increased following implementation, with no decline for several years, and no clear effect of the small increase in warning size. Reactions, mainly cognitive responses, were consistently predictive of quit attempts in Thailand, but this was only consistently so in Malaysia after the change to GHWLs. |
| Th (w5): 2132 | ||||||
| MY (w2): 1640 | ||||||
| MY (w4): 2045 | ||||||
| MY (w6): 2000 | ||||||
| 21 | Mannocci et al., 2019 | Italy | Cigarette packs | Longitudinal | Pre: 788 | Significant increases of knowledge of health risk after pictorial GHWs introduction in a short period (8–18 months). The awareness about gangrene, blindness, premature labour and erectile dysfunction registered the higher increase before and after law implementation. |
| Post: 455 | ||||||
| 22 | Mays et al., 2014 | US | Cigarette packs | RCT | 740 | Gain-framed warnings generated significantly greater motivation to quit among smokers with high perceived risks compared with smokers with low perceived risks. Among smokers with high perceived risks, gain-framed messages were superior to loss-framed messages. |
| 23 | McQueen et al., 2015 | US | Cigarette packs | Longitudinal | 202 | Participants reported low avoidance and consistent use of the stickers. Smokers consistently paid more attention to graphic than text-only labels. Only 5 of the 9 GHWs were significantly associated with greater thoughts of health risks. Thinking about quitting and stopping smoking did not differ by label. |
| 24 | Nagelhout et al., 2016 | France, Germany, Netherlands | Cigarette packs | Longitudinal | UK: 1643 | Salience decreased between the surveys in France and showed a non-significant increase in the UK, cognitive responses increased in the UK and decreased in France, forgoing cigarettes increased in the UK and decreased in France, and avoiding warnings increased in France and the UK. |
| FR: 1540 | ||||||
| 25 | Ngan et al., 2016 | Vietnam | Cigarette packs | Longitudinal | Wave 1: 1462 | Two years after implementation, salience of the pictorial GHWs was higher than one year after implementation. The proportion of respondents who tried to avoid noting pictorial GHWs decreased from 35% in wave 1 to 23% in wave 2. However, avoidance increased 1.5 times the odds of presenting quit intention compared to those respondents who did not try to avoid looking/thinking about the pictorial GHWs |
| Wave 2: 1509 | ||||||
| 26 | Nicholson et al., 2017 | Australia | Cigarette packs | Cohort | 642 | Forgoing increased significantly only for those first surveyed prior to the introduction of plain packaging (PP); however, there were no significant interactions between forgoing and the introduction of new and enlarged graphic warning labels on PP in any model. |
| 27 | Osman et al., 2016 | Mexico | Cigarette packs | Longitudinal | 1340 | All GHW responses increased over time, except putting off smoking. |
| 28 | Parada et al., 2017 | US | Cigarette packs | RCT | Intervention: 1071 | Smokers in the intervention (pictorial GHWs) group thought more about the warning message and harms of smoking, reported higher levels of fear due to warnings, experienced more negative affect, expressed more intention to quit, and forewent smoking cigarettes more than participants in the control group. |
| Control: 1078 | ||||||
| 29 | Partos et al., 2013 | Australia, Canada, UK, US | Cigarette packs | Longitudinal | AU: 576 | Reporting that GHWs make quitting over time ‘a lot’ more likely (compared with ‘not at all’ likely) was associated with a lower likelihood of relapse 1 year later and this effect remained robust across all models tested, increasing in some. Reporting that GHWs make you more likely to remain smoking free was strongly correlated with reporting that GHWs make you think about health risks. |
| CA: 478 | ||||||
| UK: 512 | ||||||
| 30 | Popova & Ling, 2014 | Canada | Moist snuff, snus, and e-cigarettes | RCT | 76 | Pictorial GHWs increased perceived harm of moist snuff and e-cigarettes. Current warning label and pictorial GHW significantly lowered positive attitudes towards e-cigarettes. |
| 31 | Schneider et al., 2012 | Germany | Cigarette packs | RCT | 44 | Pictorial GHWs were associated with a significantly higher motivation to quit. A pictorial GHW was also associated with higher fear intensity. The effect of warnings appears to be independent of nicotine dependence and self-affirmation. |
| 32 | Swayampakala et al., 2014 | Australia, Canada, Mexico | Cigarette packs | Longitudinal | AU: 1001 | Smokers in countries with GHWs describing specific health risks had greater awareness and knowledge of those specific health risks (with only few exceptions) compared to smokers in countries that do not include the same GHWs health risks (e.g., risk of blindness in Australia, but not Mexico). |
| CA: 1001 | ||||||
| MX: 1000 | ||||||
| 33 | White et al., 2008 | Australia | Cigarette packs | Longitudinal | 2432 | Attention to and processing of warning labels increased from T1 to T2. Smokers considered quitting more at follow-up (T2). |
| 34 | Yong et al., 2013 | Thailand, Malaysia | Cigarette packs and RYO packs | Longitudinal | TH (w1): 3067 | After GHW change smokers’ awareness, cognitive, and behavioral reactions increased, with cognitive and behavioral effects sustained at follow-up (Thailand). Compared to smokers who smoke generic cigarettes, smokers of RYO reported lower salience but greater cognitive reactions to the new pictorial GHWs. |
| TH (w2): 1986 | ||||||
| 35 | Yong et al., 2016 | Australia | Cigarette packs | Longitudinal | Pre: 1104 | Attentional orientation towards GHWs and reported frequency of noticing warnings increased significantly after the policy change, but not more reading. Smokers also thought more about the harms of smoking and avoided the GHWs more after the policy change, but frequency of forgoing cigarettes did not change. |
| Post: 1093 |