Supplementary Material for: Are Area-Level Socioeconomic Factors Associated with Dental Caries and Tooth Loss? A Systematic Review

Introduction: Area-level socioeconomic factors are within the social determinants of health, encompassing conditions in which people are born, grow, live, work, and age, which influence health beyond individual characteristics. This review examines the association between area-level socioeconomic factors and dental caries and tooth loss. The hypothesis is that individuals residing in more socioeconomically deprived areas experience higher odds of dental caries and tooth loss, independent of individual socioeconomic status. Methods: A systematic search was conducted in PubMed, Scopus, Embase, and Web of Science. Studies reporting clinical or self-reported dental caries or tooth loss, and evaluating area-level socioeconomic deprivation or income (neighbourhood, municipality, or region) using multilevel models were included. Results: Of 4,671 screened records, 44 studies (41 cross-sectional) published from 2006 to 2024 were included. The most common exposures were area socioeconomic deprivation indices (n=24), area average income (n=21), and the Human Development Index (HDI) (n=13). Quantitative synthesis was precluded by heterogeneity of aggregation levels, outcomes (tooth loss, caries experience, and untreated caries), and outcome measurement (dichotomous/continuous). Most studies adjusted for individual-level socioeconomic factors (82%). The hypothesised association was most consistent for tooth loss (e.g. functional dentition or edentulism, 6/6 studies), at a medium level of aggregation (13/15), and for the HDI (10/13). Studies using ordered categories frequently demonstrated clear socioeconomic gradients. Conclusion: The findings support the hypothesis that residing in more affluent areas is associated with better oral health outcomes, specifically lower levels of tooth loss and, to a lesser extent, dental caries, after adjusting for individual-level socioeconomic factors.引言：区域层面社会经济因素属于健康社会决定因素范畴，涵盖人们出生、成长、居住、工作及衰老所处的环境条件，此类因素对健康的影响超越个体自身特征。本综述旨在探讨区域层面社会经济因素与龋病（dental caries）及牙齿缺失（tooth loss）之间的关联。本研究假设为：即使在控制个体社会经济地位的前提下，居住在社会经济剥夺程度更高区域的个体，罹患龋病及出现牙齿缺失的风险更高。 方法：本研究在PubMed、Scopus、Embase及Web of Science数据库中开展系统检索。纳入标准为：研究报告了临床或自我报告的龋病（dental caries）或牙齿缺失（tooth loss）结局，并采用多水平模型（multilevel models）评估了区域层面（街区、市级或区级）的社会经济剥夺状况或收入水平。 结果：本研究共筛选出4671条文献记录，最终纳入2006年至2024年发表的44项研究（其中41项为横断面研究）。最常见的暴露因素为区域社会经济剥夺指数（n=24）、区域平均收入（n=21）及人类发展指数（HDI，Human Development Index）（n=13）。由于聚合层级、结局指标（牙齿缺失、龋病患病情况及未治疗龋病）及结局测量方式（二分类/连续性变量）存在异质性，无法开展定量合成分析。绝大多数研究（82%）均对个体层面的社会经济因素进行了校正。假设的关联在以下场景中最为一致：牙齿缺失结局（如功能性牙列或无牙颌，共6项研究均得到验证）、中等聚合层级（15项研究中有13项）及人类发展指数（HDI）（13项研究中有10项）。采用有序分类变量的研究常可观察到清晰的社会经济梯度。 结论：本研究结果支持以下假设：在控制个体层面社会经济因素后，居住在社会经济条件更优越的区域与更良好的口腔健康结局相关，具体表现为更低的牙齿缺失比例，且对龋病的保护作用相对较弱。