Yichen Zhong, Amy H. Auchincloss, Brian K. Lee, Genevieve P. Kanter

On January 1, 2017, Philadelphia implemented a beverage tax of $0.015/ounce on sugar ("regular") and sugar-substitute ("diet") beverages. The purpose of this study was to evaluate the immediate impact of the tax on residents' consumption of soda, fruit drinks, energy drinks, and bottled water. A repeat cross-sectional study design used data from a random-digit-dialing phone survey during a no-tax period (December 6-31, 2016) and a tax period (January 15-February 31, 2017) among 899 respondents in Philadelphia, Pennsylvania, and 878 respondents in three nearby comparison cities. Survey questions included frequency and volume of bottled water and beverages. Outcomes were daily consumption, and 30-day consumption frequency and volume. Propensity score-weighted difference-in-differences regression was used to control for secular time trend and confounding. Covariates were sociodemographics, BMI, health status, smoking, and alcohol use. Analyses were conducted in 2017. Within the first 2 months of tax implementation, relative to the comparison cities, in Philadelphia the odds of daily consumption of regular soda was 40% lower (OR=0.6, 95% CI=0.37, 0.97); energy drink was 64% lower (OR=0.36, 95% CI=0.17, 0.76); bottled water was 58% higher (OR=1.58, 95% CI=1.13, 2.20); and the 30-day regular soda consumption frequency was 38% lower (ratio of consumption frequency=0.62, 95% CI=0.40, 0.98). Early results suggest that the tax influenced daily consumption of regular soda, energy drinks, and bottled water. Future studies are needed to evaluate longer-term impact of the tax on sugared beverage consumption and substitutions.