The health and financial impacts of a sugary drink tax across different income groups in Canada

Abstract

Background: Overconsumption of sugar-sweetened beverages (SSBs) contributes to childhood and adult obesity and numerous related diseases, including heart disease, strokes, cancers, and type 2 diabetes. It also increases healthcare costs. Sugary drink taxes have been implemented in several countries to curb sugar intake. However, there is a concern that sugary drink taxes are regressive. This study assessed the health and financial impacts of a simulated sugary drink tax across different income groups in Canada.

Methods: A proportional multi-state life table-based Markov model simulated the 2016 Canadian population by income quintile. The model applied a 20 % tax on sugary drinks and determined the effects on type 2 diabetes and BMI-related diseases compared to no intervention. The income-specific parameters modelled included: population demographics; cross- and own-price elasticities; mean BMI; sugary drink consumption; mortality; and disease epidemiology.

Results: A 20 % sugary drink tax was estimated to reduce the consumption of sugary drinks by an average of around 15 %, with a greater reduction in the lowest income quintile. The estimated mean reduction in BMI ranged from 0.21 to 0.33, dependent upon sex and income quintile; these reductions were greater among the lower income quintiles for both females and males. The 20 % sugary drink tax was estimated to avert approximately 690,000 DALYs over a lifetime among the 2016 Canadian adult population; estimated DALYs averted were approximately 156,000, 140,000, 137,000, 134,000, and 125,000 for the lowest through to the highest income quintile, respectively. Lifetime health care savings were estimated to be $2.27bn, $2.16bn, $2.17bn, $2.12bn, and $1.98bn for the lowest through to the highest income quintile, respectively. The estimated annual tax burden for the 2016 Canadian population was $1.4bn. The average absolute tax burden was estimated to be $39.00 to $44.30 per person, with the middle-income quintile bearing the heaviest absolute tax burden. The lowest income quintile would pay the highest proportion of income in tax, implying that the tax is regressive.

Conclusions: Low-income Canadians would gain the most health benefit from a sugary drinks tax. However, the lowest income quintile would also pay the largest proportion of income in tax. A tax on sugary drinks is therefore financially regressive but forecast to reduce health disparities across Canada.

Keywords: Economic evaluation; Equity; Obesity; Sugar taxation.