The effect of tobacco tax increase on price-minimizing tobacco purchasing behaviours: A systematic review and meta-analysis.

ABSTRACT

BACKGROUND AND AIMS: Tobacco product excise taxes are a cost-effective method for reducing tobacco consumption, but industry pricing and marketing strategies encourage consumers to engage in price-minimizing behaviours (PMBs). We investigated the relationship between tobacco tax increases and PMBs, measuring whether PMBs intensify following tax increases, whether low-income consumers with higher nicotine dependence are more likely to engage in PMBs and whether PMBs are negatively related to smoking cessation. METHOD: This was a systematic review with meta-analysis of cross-sectional and longitudinal studies from seven databases up to March 2023, using studies that reported any product- and purchasing-related smoking behaviours post-tobacco tax increase in a general representative population. Sixty-eight studies were quality-assessed using the Newcastle-Ottawa scale. All studies were narratively synthesized, with five studies involving 13 068-26 575 participants providing data for pooled analyses on PMBs [purchasing lower-priced brands, roll-your-own (RYO) tobacco and cartons] pre- and post-tax increases using a random effects meta-analytical model. RESULTS: Fifty-seven studies reported on legal PMBs, and 17 studies reported illicit cigarette purchasing. Meta-analysis showed that consecutive tax increases were positively associated with purchasing RYO [odds ratio (OR) = 1.60, 95% confidence interval (CI) = 1.04-2.46], especially in higher tobacco taxing environments, with substantial heterogeneity (I2 = 96%). Lower income and higher nicotine dependence were associated with purchasing lower-priced brands and RYO, whereas higher income and nicotine dependence were associated with purchasing cartons, large-sized packs and cross-border sales. Less evidence associated illicit tobacco purchases with tax increases or PMBs with smoking cessation. CONCLUSIONS: Tobacco purchasers' PMBs vary widely by state, country and time-period within countries. Both legal and illegal PMBs, potentially influenced by industry pricing tactics, may exacerbate health inequalities and dilute the public health benefits of tobacco tax increases.