The Effect of City-Level Sugar-Sweetened Beverage Taxes on Longitudinal HbA1c and Incident Diabetes in Adults With Prediabetes.

ABSTRACT

OBJECTIVE: Prediabetes, which is a condition characterized by higher-than-normal blood glucose levels that are under the threshold for diabetes, impacts over one-third of U.S. adults. Excise taxes on sugar-sweetened beverages (SSBs) are a proposed policy intervention to lower population consumption of SSBs and generate revenue to support health-related programs, thus potentially delaying or preventing the development of diabetes in individuals with prediabetes. We leveraged data from Kaiser Permanente in California to examine the impact of SSB taxes in California on individual-level mean HbA1c levels and rates of incident diabetes. RESEARCH DESIGN AND METHODS: We compared two outcomes, mean HbA1c levels and rates of incident diabetes, among a matched cohort of adults with prediabetes who lived and did not live in SSB excise tax cities, using outcomes collected in the 6 years prior and 4 years following SSB tax implementation. We used multivariable linear mixed effects models to analyze longitudinal mean HbA1c and discrete-time survival models for incident diabetes. RESULTS: We included 68,658 adults in the analysis. In adjusted models, longitudinal mean HbA1c was 0.007% (95% CI 0.002, 0.011) higher in the tax cities compared with control individuals; while the estimated difference was statistically significant, it was not clinically significant (HbA1c <0.5%). There was no significant difference in the risk of incident diabetes between individuals living in tax and control cities. CONCLUSIONS: We found no clinically significant association between SSB taxes and either longitudinal mean HbA1c or incident diabetes among adults with prediabetes in the 4 years following SSB tax implementation.