Table 2.
Summary of study findings evaluating the impact of SSB taxes on sales, purchases and dietary intake, and transformation of results to a scaled rate ratio, search done in June 2018
| Study | Jurisdiction | Outcome | n | Measure | Main Results | RR (95% CIs) | SE | Tax Size or AVE | RR Scaled for a 10% Tax (95% CIs) | SE, Scaled | % Change, Scaled |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Falbe et al57 | Berkeley | Intake | 2679 | % change compared with control | Consumption of SSBs decreased 21% in Berkeley and increased 4% in comparison cities, P = .046 | 0.760 (0.580‐0.995) | 0.138 | 21.9 | 0.883 (0.781‐0.998) | 0.063 | ‐11.7 |
| Silver et al56 | Berkeley | Sales | 10 152 | % change | Posttax year 1 scanner data SSB sales (ounces/transaction) in Berkeley stores declined 9.6% (P < .001, volume sold per transaction) compared to estimates if the tax were not in place, but rose 6.9% (P < .001) for non‐Berkeley stores. | 0.904 (0.851‐0.960) | 0.031 | 21.9 | 0.955 (0.929‐0.982) | 0.014 | −4.5 |
| Silver et al56 | Berkeley | Intake | 1236 | % change | Self‐reported mean daily SSB intake in grams declined (−19.8%, P = .49) from baseline to posttax but was not statistically significant. | 0.802 (0.429‐1.501) | 0.320 | 21.9 | 0.905 (0.68‐1.203) | 0.145 | −9.5 |
| Vall Castello49 | Catalonia | Sales | 284 464 | Absolute difference | Purchases of SSBs are reduced by 4.7 L per product, establishment and week (standard error for absolute difference was 1.111), which implies a reduction by 15.42% with respect to the mean of SSB purchases before the reform (mean 30.48 L) | 0.846 (0.774‐0.917) | 0.043 | 11.4 | 0.900 (0.852‐0.947) | 0.027 | −10.0 |
| Caro31 | Chile | Purchases | 1795 | % change | Households decreased monthly per capita purchase volumes of (high sugar) SSBs by 3.4% (95% CI: −5.9% to −0.9%) and 4.0% by calories (95% CI: −6.3% to −1.9%) | 0.966 (0.941‐0.991) | 0.013 | 5.0 | 0.933 (0.885‐0.982) | 0.026 | −6.7 |
| Nakamura33 | Chile | Purchases | 2836 | % change | 21.6% reduction in high tax soft drink volumes purchased, P < .001 | 0.784 (0.719‐0.854) | 0.044 | 5.0 | 0.615 (0.517‐0.729) | 0.088 | −38.5 |
| Capacci et al50 | France | Purchases | 416 | % change, uncertainty reported for absolute difference | 15.3% reduction for the average household of drinks for home consumption with a standard error for the 46 mL rate difference of 0.001 (regional calculation). | 0.847 (0.841‐0.854) | 0.004 | 9.7 | 0.843 (0.836‐0.85) | 0.004 | −15.7 |
| Colchero et al54 (PLoS One) | Mexico | Sales | 57 164 | % change | Pre vs both years posttax: decline of 7.3%, P < .01 (pre vs year 1 posttax: decline of 6.2%; pre vs year 2 posttax: decline of 8.7%) | 0.927 (0.875‐0.982) | 0.029 | 6.7 | 0.893 (0.819‐0.973) | 0.044 | −10.7 |
| Colchero et al32 (J Nutr) | Mexico | Purchases | 75 954 | % change | 6.3% reduction (P < 0.001) in the observed purchases of SSBs in 2014 compared with the expected purchases in that same year based on trends from 2008 to 2012 | 0.937 (0.926‐0.948) | 0.006 | 6.7 | 0.907 (0.892‐0.924) | 0.009 | −9.3 |
| Colchero et al53 (H Affairs) | Mexico | Purchases | 6645 | % change | Purchases of taxed beverages decreased 5.5% in 2014 and 9.7% in 2015, yielding an average reduction of 7.6% over the study period, P < .01 | 0.924 (0.870‐0.981) | 0.031 | 6.7 | 0.889 (0.812‐0.972) | 0.046 | −11.1 |
| Aguilar et al52 | Mexico | Purchases | 9953 | % change | 6.3% decrease in sugar drink consumption with a standard error of 0.006 (Table 2) | 0.937 (0.926‐0.948) | 0.006 | 6.7 | 0.907 (0.892‐0.924) | 0.009 | −9.3 |
| Colantuoni and Rojas48 | Cleveland, Ohio | Sales | 720 | % change | 2% decline with a standard error of 0.04 | 0.980 (0.906‐1.060) | 0.040 | 5.0 | 0.960 (0.821‐1.123) | 0.080 | −4.0 |
| Portland, Maine | Sales | 576 | % change | 2% decline with a standard error of 0.04 | 0.980 (0.906‐1.060) | 0.040 | 5.5 | 0.964 (0.836‐1.112) | 0.073 | −3.6 | |
| Fletcher et al47 (J Public Econ ) | United States | Intake | 21 040 | Absolute difference | 1 percentage point increase in the soft drink tax rate reduces the amount of calories consumed by soda by nearly 6 cal, which is about 5% of the average calories from soda. Standard error for the −18 calorie rate difference was 7.333. | 0.762 (0.607‐0.947) | 0.114 | 4.6 | 0.554 (0.337‐0.889) | 0.247 | −44.6 |
| Fletcher et al46 (H Affairs) | United States | Intake | 20 968 | Absolute difference | 319.671 g of soda consumed between states that have ever had a soft drink tax vs vs 312.091 in those without a soft drink tax, and P = .569 for a test of the difference | 1.024 (0.941‐1.108) | 0.042 | 4.7 | 1.052 (0.878‐1.244) | 0.089 | 5.2 |
| Fletcher et al45 | United States | Intake | 35 940 | Absolute difference, per 1% tax | 1.566 increase in calories from soda (only) for every 1% increase in tax, P = .526. The mean level of calories from soft drinks was 130. (Linear specification was preferred) | 1.062 (0.882‐1.269) | 0.093 | 5.0 | 1.127 (0.778‐1.610) | 0.186 | 12.7 |
| Sturm et al44 | United States | Intake | 7414 | Absolute difference | Soda tax was associated with −0.006 less drinks per week (mean was 6.1 drinks per week), standard error for absolute difference was 0.201 | 0.999 (0.934‐1.064) | 0.033 | 3.5 | 0.997 (0.824‐1.193) | 0.094 | −0.3 |
| European Competitiveness and Sustainable Industrial Policy Consortium51 | Finland | Sales | % change | Soft drinks: “slightly downward trend” between 1999 and 2013. Since 2007, demand in decline. Years following tax implementation demand declined at a faster pace: 2011: −0.7%, 2012: −3.1%, 2013: −0.9%. Uncertainty was not available so could not be included in meta‐analysis. | |||||||
| France | Sales | % change | Cola 2012: −3.3%, 2013: −3.4%. Decrease in demand of 6.7% for regular cola for 2012 and 2013 combined. Demand for regular cola and low calorie cola has “steadily been increasing until 2011.” After 2011, “both beverages show a decline in demand.” Years following tax implementation: Regular cola: 2012: −3.3%, 2013: −3.4%. Uncertainty was not available so could not be included in meta‐analysis. | ||||||||
| Hungary | Sales | % change | Cola 2011: −2.7%, 2012: −7.5%, 2013: −6.0%. Demand for cola decreased by 10.2%. BUT, was already experiencing declining demand pretax, although decline appears to be accelerated by the tax. Uncertainty was not available so could not be included in meta‐analysis. | ||||||||
| Andalón and Gibson55 | Mexico | Purchases | 17 404 | % change | Average soda quantity acquired decreased by −4.6%. Uncertainty was not available and so could not be included in meta‐analysis. | 0.954 | 6.7 | 0.932 | −6.8 | ||
| Zhong58 | Philadelphia | Intake | 1777 | Odds ratio | OR 0.84 (CI: 0.56‐1.26), 30 day volume for SSBs was used as the primary outcome. Only odds ratio reported, so could not be included in meta‐analysis. |
0.840* (0.560‐1.260) |
0.207 | 33.3 | 0.949* (0.839‐1.073) | 0.062 | −5.1 |
Note . Scaled RRs (and corresponding scaled upper and lower CIs) were calculated to express the effect size of each study according to a per 10% change in the level of SSB tax. The calculation was done by using this formula: scaled RR = study RR (10 %/ level of jurisdiction's tax as a percentage of price ) . Absolute measures were divided the absolute change by the original level of consumption. Percentage change measures of effect were converted into a RR by adding one. If a RR was reported per 1% tax change (tax elasticity), then this measure of effect was scaled to the size of the SSB tax. If a volumetric tax was examined, the ad valorem equivalent of the jurisdiction's tax calculated from the volumetric tax and the import unit value of sweetened drinks. n = total individuals, households or sales data points analysed, eg, in the final model.
Abbreviations: AVE, ad valorem equivalent; RR, rate ratio; SE, standard error; SSB, sugar‐sweetened beverage.
*
This study reported ORs rather than rate ratio.