Abstract：
OBJECTIVE: Early childhood caries (ECC) is a widespread oral disease that harms children\'s health in China. Although previous studies have linked ECC prevalence to socioeconomic status, few have measured the degree of socioeconomic inequality. This study aimed to evaluate the socioeconomic inequality of ECC in children aged 3 to 5 years in China and identify the contributor to the inequality.
METHODS: We extracted data on 3 to 5-year-old children from the fourth National Oral Health Survey. We measured the inequality of ECC by the average household income per capita. We used the average household income per capita to measure the inequality of ECC. To describe inequality both qualitatively and quantitatively, we used the following methods: concentration curve, Erreygers-corrected concentration index, relative index of inequality and slope index of inequality. We also applied a decomposition based on the probit model to identify the factors that contributed to inequality.
RESULTS: The prevalence of ECC in Chinese preschool children was 63.11% (95% CIs: 60.54%, 65.61%). The negative value of the Erreygers-corrected concentration index (-0.0459; 95% CIs: -0.0594, -0.0324), slope index of inequality (-0.0674; 95% CIs: -0.0876, -0.0471) and the positive value of relative index of inequality (0.7484; 95% CIs: 0.6856, 0.8169) all indicated that ECC prevalence was higher among children from low-income families. The main factors contributing to inequality were average household income, parents\' educational level and living areas.
CONCLUSIONS: There is a pro-poor inequality in ECC among 3 to 5-year-old children in China.
CONCLUSIONS: To improve oral health equality, policymakers should focus more on children from low-income families, with less educated parents and living in rural areas.
METHODS: We extracted data on 3 to 5-year-old children from the fourth National Oral Health Survey. We measured the inequality of ECC by the average household income per capita. We used the average household income per capita to measure the inequality of ECC. To describe inequality both qualitatively and quantitatively, we used the following methods: concentration curve, Erreygers-corrected concentration index, relative index of inequality and slope index of inequality. We also applied a decomposition based on the probit model to identify the factors that contributed to inequality.
RESULTS: The prevalence of ECC in Chinese preschool children was 63.11% (95% CIs: 60.54%, 65.61%). The negative value of the Erreygers-corrected concentration index (-0.0459; 95% CIs: -0.0594, -0.0324), slope index of inequality (-0.0674; 95% CIs: -0.0876, -0.0471) and the positive value of relative index of inequality (0.7484; 95% CIs: 0.6856, 0.8169) all indicated that ECC prevalence was higher among children from low-income families. The main factors contributing to inequality were average household income, parents\' educational level and living areas.
CONCLUSIONS: There is a pro-poor inequality in ECC among 3 to 5-year-old children in China.
CONCLUSIONS: To improve oral health equality, policymakers should focus more on children from low-income families, with less educated parents and living in rural areas.
摘要：
目的：儿童早期龋病（ECC）是一种危害中国儿童健康的广泛口腔疾病。尽管以前的研究已经将ECC患病率与社会经济地位联系起来，很少有人衡量社会经济不平等的程度。本研究旨在评估中国3至5岁儿童ECC的社会经济不平等，并确定不平等的原因。
方法：我们从第四次全国口腔健康调查中提取了3至5岁儿童的数据。我们通过人均家庭平均收入来衡量ECC的不平等。我们使用人均家庭收入来衡量ECC的不平等。定性和定量描述不等式，我们使用了以下方法:浓度曲线,Erreygers校正浓度指数,不平等的相对指数和不平等的斜率指数。我们还应用了基于probit模型的分解来识别导致不平等的因素。
结果：中国学龄前儿童的ECC患病率为63.11％（95％CIs：60.54％，65.61%）。Erreygers校正浓度指数的负值（-0.0459；95％CIs：-0.0594，-0.0324），不平等的斜率指数(-0.0674;95%CIs:-0.0876,-0.0471)和相对不平等指数的正值(0.7484;95%CIs:0.6856,0.8169)均表明低收入家庭儿童的ECC患病率较高。造成不平等的主要因素是平均家庭收入，父母的教育水平和生活区。
结论：中国3至5岁儿童的ECC存在有利于穷人的不平等。
结论：为了改善口腔健康平等，政策制定者应该更多地关注低收入家庭的孩子，父母受教育程度较低，生活在农村地区。
方法：我们从第四次全国口腔健康调查中提取了3至5岁儿童的数据。我们通过人均家庭平均收入来衡量ECC的不平等。我们使用人均家庭收入来衡量ECC的不平等。定性和定量描述不等式，我们使用了以下方法:浓度曲线,Erreygers校正浓度指数,不平等的相对指数和不平等的斜率指数。我们还应用了基于probit模型的分解来识别导致不平等的因素。
结果：中国学龄前儿童的ECC患病率为63.11％（95％CIs：60.54％，65.61%）。Erreygers校正浓度指数的负值（-0.0459；95％CIs：-0.0594，-0.0324），不平等的斜率指数(-0.0674;95%CIs:-0.0876,-0.0471)和相对不平等指数的正值(0.7484;95%CIs:0.6856,0.8169)均表明低收入家庭儿童的ECC患病率较高。造成不平等的主要因素是平均家庭收入，父母的教育水平和生活区。
结论：中国3至5岁儿童的ECC存在有利于穷人的不平等。
结论：为了改善口腔健康平等，政策制定者应该更多地关注低收入家庭的孩子，父母受教育程度较低，生活在农村地区。
