Impact of alcohol excise taxation and structural reforms on per capita consumption in Thailand, 1995–2021: an interrupted time-series analysis

Abstract

Background Alcohol taxation is a highly effective alcohol control policy, but adjustments for inflation and affordability are essential to sustain its impact. Between 1996 and 2017, Thailand implemented 11 excise tax increases and two structural reforms. This study examines the combined effects of these changes on alcohol consumption over time. Methods Interrupted time-series analyses, adjusting for autocorrelation and seasonality, were conducted using monthly recorded adult alcohol per capita consumption (APC) data from January 1995 to December 2021. We assessed the impact of tax increase policies that affected more than 15 % of the total alcohol market, and two structural reforms. Increases in 1997–98 were combined due to their temporal proximity. Results Excise tax increases in January 1997, March 2001, and September 2007 were associated with reductions in APC of 9.7 % (95 % CI: 4.1 %, 15.0 %), 4.8 % (95 % CI: -0.9 %, 10.2 %), and 6.7 % (95 % CI: 0.6 %, 12.3 %), respectively. Structural reforms in 2013 and 2017 had on average larger effects, reducing APC by 9.3 % (95 % CI: 1.1 %, 16.8 %) and 23.0 % (95 % CI: 14.5 %, 30.6 %), respectively. Modelling indicates that without these taxation policies, total recorded APC between 1995 and 2021 could have been on average 0.56 litres (L) higher in each year, and 1.99 L higher by 2021. Conclusion Alcohol excise taxation (i.e., excise tax increases and structural reforms) significantly reduced APC in Thailand. Future taxation policies should include automatic adjustments for changes in inflation and/or disposable household income to sustain their long-term public health impact.