Changes in Population-Level Consumption of Taxed and Non-Taxed Sugar-Sweetened Beverages (SSB) after Implementation of SSB Excise Tax in Thailand: A Prospective Cohort Study

Background: Thailand has implemented a sugar-sweetened beverage (SSB) excise tax since September 2017, but questions remain about changes in individual-level SSB consumption after tax implementation. This study aimed to analyze the change in taxed and non-taxed SSB consumption in the Thai population. Method: This cohort study was carried out in 2018 and 2019. A total of 5594 persons who participated in both years were included in the analysis. Descriptive and t-test analyses were carried out in order to identify the significance of the difference between taxed and non-taxed SSB consumption in 2018 and 2019. Results: A lower mean ratio of average taxed SSBs consumed to average non-taxed SSBs consumed was found to be statistically significant (p = 0.001). That is, the decline in taxed SSB consumption is significantly greater than that of the non-taxed consumption. The greater reduction in taxed SSB consumption than the non-taxed SSB consumption was found to be significant among males, older persons, the lower-income population, and the unemployed. Conclusions: Overall, the current SSB tax has the capacity to successfully discourage consumption of SSBs with high sugar level. The decline in SSB consumption is, however, not found across all socioeconomic groups. Thresholds for SSB-tiered tax structure may have to be reviewed.