Introduction:
Plain packaging (PP) disrupts the role of tobacco industry advertising, promotion and sponsorship in sustaining the tobacco epidemic. As socioeconomic inequalities in smoking widen, the distributional impacts of tobacco control policies require increased attention. Ireland implemented PP in 2017, with a one-year “wash-out” period. This study evaluated impacts of PP overall, and by socioeconomic group, across three well-established outcome domains: tobacco product appeal; health warnings effectiveness; and perceptions of the harmful effects of smoking.

Material and Methods:
An uncontrolled before-and-after study used consecutive representative cross-sectional population surveys (2018-2019) to measure 13 PP outcome changes across three domains pre- (2018) versus post-implementation (2019). Multiple logistic regression derived Adjusted Odds Ratios (aOR) with 95% Confidence Intervals (CI) to compare outcomes post- versus pre-implementation controlling for age, gender, education level, and heaviness of smoking. A stratified analysis examined PP outcomes by education level.

Results:
Overall, significant expected policy impacts were observed across 6 of 13 outcome measures, e.g. PP implementation was associated with reduced pack appeal (aOR 2.34 (CI 1.99, 2.76), p<0.0001), and greater attribution of motivation to quit to health warnings (aOR 1.38 (CI 1.03, 1.84), p<0.03). Compared to more educated groups, people in less educated groups reported fewer significant expected policy impacts (4/13 vs 6/13 outcomes respectively); differences in effect were observed between groups across 5 outcomes. For example, versus more educated groups, people in less educated groups reported reduced pack appeal (aOR 1.44 (CI 1.09, 1.89) p=0.011 vs aOR 1.13 (CI 0.93, 1.37) p= 0.2049) but did not report greater attribution of motivation to quit to health warnings (0.81 (CI 0.44, 1.50), p=0.504 vs 1.66 (CI 1.19, 2.31), p=0.0031).

Conclusions:
These findings in Ireland join international studies to further consolidate evidence of PP effectiveness at overall population level. However, it highlights the extending evaluation to better understand the potential contribution of differential PP impacts to the complex challenge of widening socioeconomic inequalities in smoking.

This work has never been previously published. It was presented orally at the Faculty of Public Health Medicine in Ireland Scientific Meeting in 2022.