Open Access Highly Accessed Research article

The potential impact on obesity of a 10% tax on sugar-sweetened beverages in Ireland, an effect assessment modelling study

Adam DM Briggs1, Oliver T Mytton12, David Madden3, Donal O’Shea4, Mike Rayner1* and Peter Scarborough1

Author Affiliations

1 British Heart Foundation Health Promotion Research Group, Nuffield Department of Population Health, University of Oxford, Oxford, UK

2 UK Health Forum, London, UK

3 School of Economics, University College Dublin, Dublin, Ireland

4 Department of Endocrinology, St Columcille’s Hospital, Health Service Executive, Loughlinstown, Ireland

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BMC Public Health 2013, 13:860  doi:10.1186/1471-2458-13-860

Published: 17 September 2013

Abstract

Background

Some governments have recently shown a willingness to introduce taxes on unhealthy foods and drinks. In 2011, the Irish Minister for Health proposed a 10% tax on sugar sweetened beverages (SSBs) as a measure to combat childhood obesity. Whilst this proposed tax received considerable support, the Irish Department of Finance requested a Health Impact Assessment of this measure. As part of this assessment we set out to model the impact on obesity.

Methods

We used price elasticity estimates to calculate the effect of a 10% SSB tax on SSB consumption. SSBs were assumed to have an own-price elasticity of −0.9 and we assumed a tax pass-on rate to consumers of 90%. Baseline SSB consumption and obesity prevalence, by age, sex and income-group, for Ireland were taken from the 2007 Survey on Lifestyle and Attitude to Nutrition. A comparative risk assessment model was used to estimate the effect on obesity arising from the predicted change in calorie consumption, both for the whole population and for sub-groups (age, sex, income). Sensitivity analyses were conducted on price-elasticity estimates and tax pass-on rates.

Results

We estimate that a 10% tax on SSBs will result in a mean reduction in energy intake of 2.1 kcal/person/day. After adjustment for self-reported data, the 10% tax is predicted to reduce the percentage of the obese adult population (body mass index [BMI] ≥30 kg/m2) by 1.3%, equating to 9,900 adults (95% credible intervals: 7,750 to 12,940), and the overweight or obese population (BMI ≥ 25 kg/m2) by 0.7%, or 14,380 adults (9,790 to 17,820). Reductions in obesity are similar for men (1.2%) and women (1.3%), and similar for each income group (between 1.1% and 1.4% across income groups). Reductions in obesity are greater in young adults than older adults (e.g. 2.9% in adults aged 18–24 years vs 0.6% in adults aged 65 years and over).

Conclusions

This study suggests that a tax on SSBs in Ireland would have a small but meaningful effect on obesity. While such a tax would be perceived as affecting the whole population, from a health prospective the tax will predominantly affect younger adults who are the main consumers of SSBs.

Keywords:
Taxation; Obesity; Overweight; Nutrition; Sugar-sweetened beverages