Celeste Roger Keller, Nadanovsky Paulo, Ponce de Leon Antonio, Fritzell Johan
Universidade Estadual do Rio de Janeiro, Instituto de Medicina Social, Rio de Janeiro, Brazil.
Soc Sci Med. 2009 Nov;69(10):1468-75. doi: 10.1016/j.socscimed.2009.08.005. Epub 2009 Sep 16.
We evaluate the association between income inequality (Gini index) and oral health and in particular the role of alternative models in explaining this association. We also studied whether or not income at the individual level modifies the Gini effect. We used data from an oral health survey in Brazil in 2002-2003. Our analysis included 23,568 15-19 and 22,839 35-44 year-olds nested in 330 municipalities. Different models were fitted using multilevel analysis. The outcomes analysed were the number of untreated dental caries (count), having at least one missing tooth (dichotomous) and being edentulous (dichotomous). To assess interaction as a departure from additivity we used the Synergy Index. For this, we dichotomized the Gini coefficient (high vs low inequality) by the median value across municipalities and the individual income in the point beyond which it showed roughly no association with oral health. Adjusted rate ratio of mean untreated dental caries, respectively for the 15-19 and 35-44 age groups, was 1.12 and 1.16 for each 10 points increase in Gini scale. Adjusted odds ratio of a 15-19 year-old having at least one missing tooth or a 35-44 year-old being edentulous was, respectively, 1.19 and 1.01. High income inequality had no statistically significant synergistic effect with being poor or living in a poor municipality. Higher levels of income inequality at the municipal level were associated with worse oral health and there was an unexplained residual effect after controlling for potential confoundings and mediators. Municipal level income inequality had a similar, detrimental effect, among individuals with lower or higher income.
我们评估收入不平等（基尼指数）与口腔健康之间的关联，特别是替代模型在解释这种关联中所起的作用。我们还研究了个体层面的收入是否会改变基尼效应。我们使用了2002年至2003年巴西口腔健康调查的数据。我们的分析纳入了嵌套在330个市中的23568名15至19岁以及22839名35至44岁的人群。使用多水平分析拟合了不同模型。分析的结果是未治疗龋齿的数量（计数）、至少有一颗缺失牙（二分变量）以及无牙（二分变量）。为了评估交互作用是否偏离可加性，我们使用了协同指数。为此，我们根据各市的中位数将基尼系数二分（高不平等与低不平等），并根据个体收入在大致与口腔健康无关联的那个点进行二分。在基尼系数每增加10个点时，15至19岁和35至44岁年龄组未治疗龋齿平均数的调整率比分别为1.12和1.16。15至19岁至少有一颗缺失牙或35至44岁无牙的调整比值比分别为1.19和1.01。高收入不平等与贫困或生活在贫困市并无统计学上显著的协同效应。市级层面较高的收入不平等水平与较差的口腔健康相关，在控制了潜在的混杂因素和中介因素后仍存在无法解释的残余效应。市级层面的收入不平等在低收入或高收入个体中具有类似的有害影响。
