National taxation on sugar-sweetened beverages and its association with overweight, obesity, and diabetes

Background: Consumption of sugar-sweetened beverages (SSBs) has been linked to several adverse health outcomes, thus many countries introduced taxation to reduce it. Objectives: To summarize national SSB taxation laws and to assess their association with obesity, overweight and diabetes. Methods: We conducted a systematic scoping review up to January 2022 on PubMed, Web of Science, Embase, and Google Search to identify taxes on SSBs. An interrupted time series analysis (ITSA) was conducted on 17 countries with taxation implemented in 2013 or before to evaluate the level and slope modifications in the rate of change of standardized prevalence rates of overweight, obesity, and diabetes. Random-effects meta-regression was used to assess whether year of entry into force of the law, national income, and tax design affected observed results. Results: We included 76 tax laws issued between 1940 and 2020 by 43 countries, which were heterogeneous in terms of tax design, amount, and taxed products. Among children and adolescents, ITSA showed level or slope reduction for prevalence of overweight and obesity in 5 (Brazil, Samoa, Palau, Panama, Tonga) and 6 (El Salvador, Uruguay, Nauru, Norway, Palau, Tonga) countries out of 17, respectively. No clear pattern of modification of results according to investigated factors emerged from the meta-regression analysis. Conclusions: Taxation is highly heterogeneous across countries in terms of products and design, which might influence its effectiveness. Our findings provide some evidence regarding a deceleration of the increasing prevalence rates of overweight and obesity among children occurring in some countries following introduction of taxation. PROSPERO registration number: CRD42021233309.