Supplementary Material for: Italian Deprivation Index and Dental Caries in 12-Year-Old Children: A Multilevel Bayesian Analysis

Evidence from the literature has shown that people with a lower socioeconomic status enjoy less good health than people with a higher socioeconomic status. The Italian deprivation index (DI) was used with the aim to evaluate the association between the DMFT index and risk factors for dental caries, including city population and DI. The study included 4,305 12-year-old children living in 38 cities classified by demographic size as small, midsize and large. Zero-inflated negative binomial multilevel regression models were used to assess risk factors for DMFT and to address excess of zero DMFT and overdispersion through a Bayesian approach. The difference in the average level of DMFT among children living in cities with different DI quintile was not statistically significant (p = 0.578). The DI and ln(population), included as city-level fixed effects in the two-level variance components model, were not statistically significant. Consuming sweet drinks on average increased the mean DMFT of a susceptible child, while having a highly educated mother reduced it. Unobserved heterogeneity among cities was detected for the probability to be non-susceptible to caries (city-level variance = 0.26 with 95% credibility interval 0.09-0.57), while no territorial effect was found for the mean DMFT of the susceptible children. Our results suggest that the DI and city population did not play a role in explaining between-city variability. Interventions against social deprivation can be influential on the perception of oral health in Italian 12-year-old children to the extent that they can also affect individual level factors.

已有文献证实，社会经济地位较低人群的健康状况劣于社会经济地位较高人群。本研究采用意大利贫困指数（Italian deprivation index, DI），旨在探究龋失补牙指数（DMFT index）与龋齿危险因素（包括城市人口规模与DI）之间的关联。本次研究纳入了来自38座按人口规模划分为小型、中型及大型的城市的4305名12岁儿童。本研究采用零膨胀负二项多层回归模型，通过贝叶斯方法评估DMFT的危险因素，并处理DMFT零值过多与过度离散的问题。居住于不同DI五分位城市的儿童，其平均DMFT水平的差异无统计学意义（p=0.578）。在两水平方差成分模型中，作为城市层面固定效应纳入的DI与对数人口（ln(population)）均未表现出统计学显著性。平均而言，饮用甜饮料会升高易感儿童的平均DMFT水平，而母亲受教育程度较高则会降低该水平。在儿童对龋齿不易感的概率维度上，检测到城市间存在不可观测异质性（城市层面方差为0.26，95%可信区间为0.09~0.57）；但未发现易感儿童的平均DMFT存在地域效应。本研究结果表明，DI与城市人口规模无法解释城市间的变异情况。针对社会贫困的干预措施可通过作用于个体层面因素，进而对意大利12岁儿童的口腔健康认知产生影响。