Abstract Introduction We present data on 20-year (2002-2022) trends in reactions of smokers to Health Warning Label (HWL) changes (e.g., increasing warning size, requiring graphic images, mandating standardized packaging) in Canada, England, and Australia, compared to the US where HWLs did not change. Methods We analyzed weighted data from 16 waves of the International Tobacco Control Four Country Survey, comprising 99 438 observations from 49 034 adults (ages 18+) who smoked cigarettes (daily or non-daily), tracking indicators of HWL effectiveness including noticing HWLs and related thoughts about harms from smoking and quitting. Results The first HWL change studied in each country (Canada-2001; England-2003; Australia-2006) had the largest impact on all indicators of HWL effectiveness; subsequent changes in all three countries had less or no additional impact. Over 20 years, noticing and quitting thoughts (for daily smoking) decreased significantly in the US. In the last three waves (2018-2022), noticing remained lowest in the US. Thinking about harm and quitting were lower in the US than in Canada and England, but in Australia, levels of “Thinking about harms” were significantly lower than in the US. People smoking non-daily maintained higher levels on some key measures than those smoking daily. Conclusions In countries with long histories of public education about smoking harms, periodically strengthening HWLs on cigarette packs appears to have diminishing impacts on smokers’ reactions with long-term impacts of strong warnings small, especially for people smoking daily. The findings suggest short-term impacts of HWLs relate to the change from previous HWLs and not their absolute magnitude. Implications HWLs on cigarette packs remain important for discouraging smoking, but the effects of strengthening warnings on smokers’ reactions decline with time and are smaller where HWLs were already strong. Sustained effects may be greater for non-daily smokers. Countries with weak or no HWLs may benefit in the medium term from stronger HWLs, though returns diminish as HWL coverage increases. Future smoking models should not assume long-term large cessation effects from stronger HWLs as they can do in the short term but allow for a range of smaller impacts. This study did not assess HWLs’ impact in preventing uptake.
Dhungel et al. (Tue,) studied this question.