Introduction
Dental caries (tooth decay) is the most common non-communicable disease globally.1 In England, tooth extraction due to caries is the main reason for elective admission to hospital in children aged 5–9 years and nearly 90% of extractions in young children are due to decay.2 When left untreated, childhood dental caries is associated with pain, problems eating and socialising, and reduced school attendance. In England, approximately 60 000 school days are missed by children each year due to tooth extractions in hospital.2 The requirement for general anaesthesia, which itself is associated with distress, tiredness and bleeding,3 is the primary reason children attend hospital for tooth extractions and is most common in young children (<4 years) and when pain is widespread.4
Oral health among children has been improving for more than a decade, although large inequalities still exist, with children living in the most socioeconomically deprived areas having twice the number of decayed, missing (due to decay) and filled teeth (DMFT) as those from the least deprived.2 Population-level interventions that have the potential to improve oral health, particularly in early-life and in deprived communities, are an important component in addressing inequalities in oral health. A multitude of risk factors for dental caries have been identified including socioeconomic factors,5 less-than-twice daily toothbrushing,6 frequent exposure to free dietary sugars1 and (in infants) frequent bottle feeding especially at bedtime.7 While the UK government has concluded that water fluoridation is a safe and cost-effective way to reduce childhood tooth decay,5 it is not universally implemented. Furthermore, fluoridation schemes on their own are not sufficient to completely prevent tooth decay meaning additional interventions are necessary.1
WHO recommends added sugar should be limited to less than 10% of energy intake and that restricting sugars below 5% would provide further benefits to health, including dental health.1 In England, sugar-sweetened beverages (SSBs) are a major source of dietary added sugars in children, accounting for around 30% of added sugars in children 1–3 years and over 50% by late adolescence.8 WHO has recommended taxation of SSBs in order to reduce consumption of sugar9 and to date over 50 countries have implemented SSB taxes.10
In March 2016, the UK government announced a soft drinks industry levy (SDIL) with the aim of reducing sugar intake.11 The two-tier tax, which was implemented in April 2018, is designed to encourage manufacturers to reformulate their drinks rather than pass the tax on to the consumer. Manufacturers of soft drinks containing ≥8 g of sugar/100 mL are subject to a levy of £0.24 /L and those with ≥5 to <8 g of sugar/100 mL are taxed at £0.18 /L. Soft drinks containing <5 g/100 mL sugar are not liable for the levy and 100% fruit juices, powder to make drinks, milk and milk-based drinks and drinks with 1.2% alcohol by volume or more are exempt irrespective of sugar content. Through reformulation, the UK SDIL led to large reductions in the sugar levels in soft drinks12 and there was a reduction in sugar purchased from soft drinks.13 Furthermore, the SDIL was found to be associated with an 8% relative reduction in prevalence of obesity in girls aged 10/11 years who were in their last year of primary school education; however, this was not found in boys of the same age or in younger children who were in their first year of primary school.14
While the relationship between SSBs and dental caries is well established, there is limited evidence on the impacts of SSB taxes on oral health. One microsimulation study reported that an SSB tax alone was unlikely to have a significant impact on dental caries.15 However, other modelling studies have predicted that SSB taxes, based on a 20% tax16–18 or reformulation,19 would lead to reductions in dental caries and school absences attributable to dental health.20 These studies almost exclusively focus on age groups with permanent dentition, with some indicating the greatest benefits in children aged 15–19 years16 and 6–12 years,18 or in children16 and adults17 from lower income households.
We are aware of only one prior empirical study on a sugar tax and dental health. That study reported that taxes on unhealthy foods and drinks in Mexico were associated with a reduction in dental caries in adults. Associations in children aged 1–12 years were lower than in adults and no associations were observed in children aged 1–5 years.21 However, the study did not specifically examine tooth extractions due to dental caries—an indicator of more severe caries, especially in younger children.
We used hospital episode data from England to study changes in the incidence rates of hospital admission for carious tooth extraction in children in the 22 months following the implementation of the UK SDIL (1) overall, (2) by age and (3) by area-based deprivation.