Short-term changes in quitting-related cognitions and behaviours after the implementation of plain packaging with larger health warnings: findings from a national cohort study with Australian adult smokers

BACKGROUND: Plain packaging (PP) with larger graphic health warnings (GHWs) was implemented in Australia in late 2012. This study examined effects of these packaging changes on short-term changes in quitting-related cognitions and behaviours. METHODS: We used a series of cohorts of Australian adult cigarette smokers originally sourced from a nationally representative cross-sectional tracking survey, followed up approximately 1 month after their baseline interview (n(weighted)=5441). Logistic regression analyses compared changes in seven quitting-related outcomes over this 1-month follow-up period for the cohorts surveyed before PP, over the period of transition to PP, and during the first year of PP, adjusting for baseline levels of the outcome and covariates. RESULTS: Compared to the referent group of smokers who completed their follow-up survey pre-PP, those who were followed-up in the early transition period showed significantly greater increases in rates of stopping themselves from smoking (OR=1.51, 95% CI (1.08 to 2.10)) and higher quit attempt rates (OR=1.43, 95% CI (1.00 to 2.03)), those followed-up in the late transition period showed greater increases in intentions to quit (OR=1.42, 95% CI (1.06 to 1.92)) and pack concealment (OR=1.55, 95% CI (1.05 to 2.31)), and those followed-up in the first year of PP showed higher levels of pack concealment (OR=1.65, 95% CI (1.01 to 2.72)), more premature stubbing out of cigarettes (OR=1.55, 95% CI (1.01 to 2.36)), and higher quit attempt rates (OR=1.52, 95% CI (1.01 to 2.30)). CONCLUSIONS: These findings provide some of the strongest evidence to date that implementation of PP with larger GHWs was associated with increased rates of quitting cognitions, microindicators of concern and quit attempts among adult cigarette smokers