The Impacts of Sugar Taxation Policies on Oral Health: A Mixed Methods Study

Background: Sugar-sweetened beverage (SSB) consumption is associated with increased risks of several health conditions. The Chilean government implemented a SSB tax as part of a tax reform in 2014. However, evidence on the effects of such taxation policies on oral health is limited. In this thesis, I aimed to estimate the impacts of Chile’s Sugar Tax on population oral health. Methods: I used convergent mixed methods across three linked studies: i) a systematic review exploring the association between different levels of SSB consumption and risks of caries and erosion; ii) a quantitative study assessing distributional changes in SSB consumption levels following implementation of Chile’s Sugar Tax policy; and iii) a qualitative case study exploring the policymaking process in Chile and its implications for oral health. Results: People who consume larger quantities of SSB have greater odds of having caries and erosion, and higher caries rates than people who consume smaller amounts. Baseline levels of SSB consumption were high in Chile and increased further after implementation of the Sugar Tax. Between 2011/12 and 2016/17 there was a net movement from low to high consumption levels for all socioeconomic groups, suggesting that future consumption levels will continue to expose the population to serious dental risk. The apparent failure of the policy might be explained by sub-optimal design resulting from a policymaking process that was more focused on raising revenue than improving population health, and which lacked transparency, public awareness, and a clear evidence base. Conclusion: Chile’s Sugar Tax had the potential to reduce SSB consumption and lower the population risk of oral disease, but policy implementation was flawed. Taxation policy remains a potentially useful tool for improving dental public health, but a more public health-oriented and evidence-informed policymaking process is required, which combines taxation changes with complementary public health approaches.