Dataset Information

Evaluation of Changes in Grams of Sugar Sold After the Implementation of the Seattle Sweetened Beverage Tax

ABSTRACT: Key Points

Question

To what extent were reductions in grams of sugar sold from taxed beverages offset by increases in sugar sold from potential substitution to untaxed beverages and foods after the 2018 implementation of the Sweetened Beverage Tax in Seattle, Washington?

Findings

In this study of beverage and food universal product codes using difference-in-differences analysis, after accounting for potential substitution to untaxed beverages, sweets, and stand-alone sugar, there were net reductions in grams of sugar sold from taxed sugar-sweetened beverages of 18% in year 1 post tax and 19% in year 2 post tax.

Meaning

Findings of this study suggest that sugar-sweetened beverage taxes may yield permanent reductions in added sugars sold from sugar-sweetened beverages in food stores.

Importance

Adults and children routinely exceed recommended intake amounts of added sugars established by dietary guidelines. Taxes are used as a policy tool to reduce demand for sugar-sweetened beverages (SSBs) given consumption-related adverse health outcomes but may induce substitution to other sources of added sugars.

Objective

To examine the extent to which changes in grams of sugar sold from taxed beverages may be offset by changes in grams of sugar sold from untaxed beverages, sweets, and stand-alone sugar after the implementation of the Seattle, Washington, Sweetened Beverage Tax (SBT) on January 1, 2018.

Design, Setting, and Participants

This study used difference-in-differences analyses to examine changes in grams of sugar sold from taxed and untaxed products in Seattle compared with Portland, Oregon, at year 1 and year 2 post tax. This study used Nielsen scanner data from supermarkets and mass merchandise as well as grocery, drug, convenience, and dollar stores on unit sales and measurements for beverage and food product universal product codes (UPCs) for each site for the pretax period (January 8-December 30, 2017) and the corresponding weeks in year 1 post tax (2018) and in year 2 post tax (2019). Nutritional analyses assessed grams of sugar for each UPC. The analytical balanced sample included 1326 taxed beverage UPCs, 239 untaxed beverage UPCs, 2054 sweets UPCs, and 81 stand-alone sugar UPCs. Statistical analysis was performed from January to August 2021.

Exposures

Implementation of the Seattle SBT.

Main Outcomes and Measures

Changes in grams of sugar sold from taxed beverages, untaxed beverages, sweets, and stand-alone sugar.

Results

At both year 1 and year 2 post tax in Seattle compared with Portland, grams of sugar sold from taxed beverages decreased 23% (year 2 posttax ratio of incidence rate ratios [RIRR] = 0.77; 95% CI, 0.73-0.80). Sugar sold from untaxed beverages increased at year 1 post tax by 4% (RIRR = 1.04; 95% CI, 1.00-1.07) with no change at year 2 post tax. Sugar sold from sweets increased by 4% at both year 1 and year 2 post tax (year 2 posttax RIRR = 1.04; 95% CI, 1.03-1.06). There were no changes in stand-alone sugar sold.

Conclusions and Relevance

This study using difference-in-differences analysis found a net 19% reduction in grams of sugar sold from taxed SSBs at year 2 post tax after accounting for changes in sugar sold from untaxed beverages, sweets, and stand-alone sugar. These results suggest that SSB taxes may effectively yield permanent reductions in added sugars sold from SSBs in food stores. This study uses difference-in-differences analysis to assess the association between introducing a sugar-sweetened beverage tax and net added sugars sold from sugar-sweetened beverages, after accounting for potential substitution to other key sources of added sugars.

SUBMITTER: Powell L

PROVIDER: S-EPMC8571660 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ImportanceHealth taxes are policy tools used to reduce harmful consumption of products and raise tax revenue, and they may also be associated with signaling (ie, informational and educational) factors that enhance their impact.ObjectivesTo examine changes in prices and volume sold of sweetened beverages following the implementation and repeal of the Cook County, Illinois, Sweetened Beverage Tax (SBT) compared with the comparison site of St Louis County and city, Missouri, which did not impose a tax.Design, setting, and participantsThis study used interrupted time series analyses to assess changes in price and volume sold of taxed (based on beverage type and sweetener status) and untaxed beverages in Cook County compared with St Louis following the implementation of the SBT on August 2, 2017, and its repeal effective December 1, 2017. Statistical analysis was performed from January to June 2020.ExposuresImplementation and repeal of the Cook County SBT.Main outcomes and measuresChanges in taxed and untaxed beverage prices and volume sold. Nielsen food store scanner data were obtained for weekly volume and dollar amount sold of nonalcoholic beverage universal product codes (UPCs) for each site in supermarkets and mass merchandise, grocery, drug, convenience, and dollar stores.ResultsThe analytic samples included 16 510 UPCs for volume and 2141 UPCs (balanced sample) for prices for 122 pretax weeks, 16 tax weeks, and 35 postrepeal weeks. Compared with St Louis, posttax implementation in Cook County resulted in a level increase in taxed beverage prices of 1.13 cents per fluid ounce (95% CI, 1.01 to 1.25 cents per fluid ounce), representing a slight overshifting, followed by a posttax repeal level decrease of -1.19 cents per fluid ounce (95% CI, -1.33 to -1.04 cents per fluid ounce), with no resulting change pretax to posttax repeal. Volume sold of taxed beverages in Cook County compared with St Louis exhibited a posttax implementation level decrease of 25.7% (β = -0.297; 95% CI, -0.415 to -0.179) and a posttax repeal level increase of 30.5% (β = 0.266, 95% CI, 0.124 to 0.408), with no net change in volume sold from pretax to 8 months after repeal.Conclusions and relevanceThis study using interrupted time series analysis found no net change in volume sold of taxed beverages following the implementation and repeal of the Cook County SBT, suggesting the tax had no signaling association. Repeals of such taxes may fully reverse their associations with reduced demand and harms associated with sweetened beverage intake.

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