Data Sheet 1_Using system dynamics mapping to explore synergy in an equity-focused obesity prevention framework.docx

IntroductionAddressing health inequities across chronic diseases is a critical public health objective, and policy, systems, and environmental (PSE) change approaches are integral to achieving this goal. However, assumptions about mechanisms of effect or population salience of PSE approaches do not necessarily generalize to inequitable social and economic contexts, partially due to limited ability to operationalize the dynamic complexity of such contexts. Systems thinking applications have the potential to characterize this complexity and improve understanding of where and how to intervene.
MethodsThe Getting to Equity in Obesity Prevention Framework (GTE) posits a theory of change involving PSE-related considerations for achieving equity grouped into four categories with a general systems feedback structure. We used systems mapping with a case study to explore the anticipated synergy across categories of the GTE. Data were extracted from a narrative account of childhood obesity prevention initiatives in a predominantly African American and Hispanic, urban public-school district: the Philadelphia Childhood Obesity Declines Project. Project documentation described PSE strategies and contextual influences thought to have contributed to concurrently observed declines in child obesity prevalence and disparities in this population.
ResultsOur final dynamic framework, which was anchored by Philadelphia's Universal Feeding Pilot for school meals, identified synergies among intervention strategies. The systems map revealed how planned and unplanned processes accumulated to align with the observed disparities reductions in the participating school district, consistent with the GTE theory of change. Community context dynamics, which evolved over time, were prominent features of the map.
DiscussionThis case study enhances the utility of the GTE framework when paired with systems mapping enabled by detailed documentation of PSE initiatives and relevant contextual influences. This suggests that prospective mapping of considerations prompted by the GTE could improve anticipation of unplanned pathways, intervention design, and implementation and supports a need for greater priority for using systems mapping or other systems science tools and methodologies in obesity-prevention research and practice.

引言
解决各类慢性病相关的健康公平性问题是公共卫生领域的核心目标，而政策、系统与环境（Policy, Systems, and Environmental, PSE）变革方法是实现该目标的关键组成部分。然而，关于PSE方法的作用机制或人群显著性的假设，未必能推广至存在社会与经济不公平性的场景中，部分原因在于难以将此类场景的动态复杂性进行可操作化处理。系统思维应用则有望刻画这类复杂性，并提升对干预时机与方式的认知。

研究方法
《肥胖预防公平性实现框架》（Getting to Equity in Obesity Prevention Framework, GTE）提出了一套变革理论，围绕实现健康公平的相关PSE要素展开，该理论被划分为四大类别，并具备通用系统反馈结构。本研究采用系统映射结合案例研究的方法，探究GTE各类别间的预期协同效应。研究数据提取自一个以非裔美国人与西班牙裔群体为主的城市公立学区的儿童肥胖预防举措叙事性记录——费城儿童肥胖率下降项目（Philadelphia Childhood Obesity Declines Project）。项目文档记录了被认为同时推动了该群体儿童肥胖患病率下降与公平性差距改善的PSE策略与场景影响因素。

研究结果
本研究最终得到的动态框架以费城学校供餐通用供餐试点（Philadelphia's Universal Feeding Pilot for school meals）为核心锚点，明确了各类干预策略间的协同关系。系统映射图揭示了计划性与非计划性过程如何累积，最终与参与学区观察到的公平性改善结果相契合，这与GTE的变革理论一致。随时间演变的社区场景动态特征，是该映射图的核心显著特征。

讨论
本案例研究结合对PSE举措与相关场景影响因素的详细记录，借助系统映射方法，提升了GTE框架的应用价值。这表明，基于GTE框架引导的前瞻性系统映射，能够提升对非计划性路径的预判能力，优化干预设计与实施流程；同时也呼吁在肥胖预防研究与实践中，应更优先采用系统映射或其他系统科学工具与方法。