The impact of the sugar tax on childhood dental caries in England
| ISRCTN | ISRCTN17412377 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN17412377 |
| ClinicalTrials.gov (NCT) | Nil known |
| Clinical Trials Information System (CTIS) | Nil known |
| Protocol serial number | NIHR159649 |
| Sponsor | Queen Mary University of London |
| Funder | National Institute for Health and Care Research |
- Submission date
- 17/07/2024
- Registration date
- 02/08/2024
- Last edited
- 22/07/2024
- Recruitment status
- No longer recruiting
- Overall study status
- Ongoing
- Condition category
- Oral Health
Plain English summary of protocol
Background and study aims
Many young children in England suffer from tooth decay (holes in teeth). The disease leads to pain and trouble chewing. Many of these children will end up in hospitals to have their teeth pulled out. Tooth decay is common among children in poor and rural areas. It is also common among ethnic groups. Soft drinks play a major role in this problem. They are a main source of sugars in children’s diets. They are also a major cause of tooth decay. Reducing the intake of soft drinks through health policies could reduce the high rates of tooth decay. Groups at risk of tooth decay will benefit more. The UK government enforced a tax on soft drinks in April 2018. A recent study showed a promising 12% decline in tooth extractions done in hospitals following the tax. Yet, it is still unclear whether the tax helped reduce the gap in tooth decay rates between social groups. Some people argue that the tax unfairly affects the poor. They will pay more taxes, as a share of their income, to consume soft drinks. This study aims to address two questions: 1. How does the sugar tax impact the distribution of severe tooth decay across social groups, ethnic backgrounds, and living areas? and, 2. What are the economic benefits of the sugar tax?
Who can participate?
Children aged 17 years old and under in England who have existing data on tooth extractions in hospitals in England between 2008 and 2024
What does the study involve?
The study will check for changes in tooth extractions in hospitals before, during, and after the sugar tax was enforced. These checks will be done across social groups, ethnic groups and areas. The second part of the project will calculate public savings due to the sugar tax. The study findings will be shared in various ways. These include workshops, layperson sum-ups, and press releases. Website content will be created for the public, health authorities, consultants, and service managers. Also, the results will be presented in papers and oral reports.
What are the possible benefits and risks of participating?
This study will not recruit participants. The people in the Lay Advisory Group will be compensated for their time and effort, receive relevant training (as needed) and get a chance to gain experience in project management, research activities and dissemination of findings.
Where is the study run from?
Queen Mary University of London
When is the study starting and how long is it expected to run for?
July 2024 to January 2026
Who is funding the study?
National Institute for Health and Care Research (NIHR) (UK)
Who is the main contact?
Prof Eduardo Bernabe, e.bernabe@qmul.ac.uk
Contact information
Public, Scientific, Principal investigator
Centre for Dental Public Health & Primary Care
Institute of Dentistry
Queen Mary University of London
Office 7, Floor 4, Royal London Dental Hospital
Turner Street
London
E1 2AD
United Kingdom
 ORCID ID |
0000-0002-1858-3713 |
|---|---|
| Phone | 44 (0)20 7882 3704 |
| e.bernabe@qmul.ac.uk |
Study information
| Primary study design | Observational |
|---|---|
| Study design | Quasi-experimental design |
| Secondary study design | Cohort study |
| Study type | Participant information sheet |
| Scientific title | The distributional and financial impacts of the soft drinks industry levy on childhood dental caries in england |
| Study objectives | The aim of this study is to evaluate the impact of the soft drinks industry levy (SDIL) on social inequalities in severe dental caries among children in England and resulting financial outcomes. |
| Ethics approval(s) | Ethics approval not required |
| Ethics approval additional information | This project is based on secondary analysis of adminsitrative data. |
| Health condition(s) or problem(s) studied | Childhood dental caries |
| Intervention | The soft drinks industry levy (SDIL) came into effect in England on 6th April 2018. The SDIL is a two-tiered levy: drinks with >=8 g of sugar per 100 ml are taxed at 24 pence per litre (higher levy tier) while drinks with 5 to <8 g of sugar per 100 ml are taxed at 18 pence per litre (lower levy tier). Drinks with <5 g of sugar per 100 ml are not levied. In April 2023, the SDIL was extended to include packaged concentrates which are mixed with sugar and diluted by a fountain machine to dispense a drink containing a total sugar content of 5+ g per 100 ml. |
| Intervention type | Other |
| Primary outcome measure(s) |
Social inequalities (absolute and relative) in admission rates for caries-related extractions according to area deprivation, ethnicity and urbanicity measured using NHS Digital data at one time point |
| Key secondary outcome measure(s) |
The following secondary outcome measures assess the inequalities in the below negative control outcomes to account for confounding events and co-interventions ad are measured using NHS Digital data at one time point. These control outcomes are common reasons for hospitalization among children that were affected by the lockdowns during the pandemic but are unlikely to be affected by the SDIL: |
| Completion date | 31/01/2026 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Child |
| Lower age limit | 0 Years |
| Upper age limit | 17 Years |
| Sex | All |
| Target sample size at registration | 4 |
| Key inclusion criteria | Children that were admitted to hospital for the primary or control outcomes between 2008 and 2024 |
| Key exclusion criteria | Not meeting the participant inclusion criteria |
| Date of first enrolment | 01/11/2024 |
| Date of final enrolment | 30/06/2025 |
Locations
Countries of recruitment
- United Kingdom
- England
Study participating centre
Mile End Road
London
E1 4NS
United Kingdom
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|---|
| IPD sharing plan summary | Not expected to be made available |
| IPD sharing plan | The datasets generated during and/or analysed during the current study are not expected to be made available due to an existing agreement with NHS Digital that prevents us from sharing the data with third parties. |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
Editorial Notes
18/07/2024: Study's existence confirmed by National Institute for Health and Care Research (NIHR) (UK).
