英国ソフトドリンク産業税と虫歯関連抜歯における不平等の影響

This study evaluated the impact of the Soft Drinks Industry Levy (SDIL) on socioeconomic inequalities in hospital admissions for caries-related extractions in England. The study used monthly data on hospital admissions in NHS hospitals in England between March 2007 and December 2024 for 0- to 17-y-olds. Admission rates for caries-related extractions were standardised by population size (per 100,000 person-months) and stratified by area deprivation quintiles. The slope and relative indices of inequality (SII and RII) were used to evaluate the magnitude of the absolute and relative inequalities in admission rates by area deprivation. Admission rates for tonsillectomy were chosen as a negative control outcome. A segmented regression model was fitted with a parameterization that incorporated 4 key policy and contextual phases: SDIL announcement, implementation, COVID-19 lockdown, and postlockdown recovery. When the counterfactual and observed trends were compared, there were absolute reductions in the SII for caries-related extractions of 3.89 (95% CI: 2.38, 5.39) and 9.27 (95% CI: 7.15, 11.40) at 22 and 80 mo after implementation, corresponding to relative reductions of 9.16% (95% CI: 3.18, 15.13) and 25.54% (95% CI: 15.74, 35.34), respectively. There were also absolute reductions in the RII of 0.03 (95% CI: 0.01, 0.05) at 22 and 80 mo after implementation, corresponding to relative reductions of 13.52% (95% CI: 4.56, 22.48) and 12.74% (95% CI: 4.49, 20.99). No differences in SII or RII were observed for tonsillectomy admission rates. The introduction of the SDIL was associated with reductions in deprivation-related inequalities in admission rates for caries-related extractions among children in England.