The Impact of Improvements in Built- and Social-Environments and Housing on Obesity in Public Housing Residents: Evidence from a Natural Experiment in South Los Angeles

摘要 肥胖是一个首要的公共卫生问题，其患病率在弱势群体中继续增加。 有证据表明，肥胖与邻里建筑和社会环境特征有关。 这些包括步行性、锻炼机会、绿色空间、食品店和社会凝聚力。但它不是 明确这些特征本身是否会导致肥胖。确定因果关系很重要， 公共卫生努力减少健康差距。我们建议通过研究一种自然的 在一个高度贫困的城市社区进行实验。洛杉矶市正在重新开发乔丹唐斯， 700个单位的过时公屋计划。在5年内，重建将建立-（1）700个新单位， 现有居民，（2）700个新的混合收入住房居民单位，将改变社会环境， (3)一个新的社区中心与健身房，（4）零售空间，将提供健康饮食的机会，（5） 绿色空间，将增加身体活动的机会，以及（6）额外的建筑环境 促进身体活动和健康饮食的改进措施（例如步行和自行车道，街道 照明）。我们的目标是研究这些改善对约旦唐斯居民身体质量指数的影响 (BMI)超重和肥胖。在目标1中，我们将比较约旦唐斯的这些结果的变化 居民和对照组（2个类似公共住房项目的居民）5年。在目标2中，我们 理清重建的三个主要组成部分的影响：建筑环境，社会 环境和新住宅。我们会利用重建计划 发生在几个阶段。在次要目标3中，我们将评估重建为什么会影响BMI， 超重和肥胖。为了做到这一点，我们将跟踪身体活动，饮食行为，个人和社会 调解员我们的数据收集将包括亲自调查，24小时饮食回忆和加速度计。最后， 在次要目标4中，我们将探讨性别、种族和年龄的调节作用。我们的研究是时间- 敏感，因为重建的第一阶段将于2018年第四季度完成。因此，征聘和 基线数据收集必须在2018年秋季完成。

ABSTRACT Obesity is a top public health concern and its prevalence continues to increase in disadvantaged populations. Evidence suggests that obesity is associated with neighborhood built and social environment characteristics. These include walkability, exercise opportunities, green space, food outlets and social cohesion. But it is not clear whether these characteristics themselves cause obesity. Establishing causality is important to inform public health efforts to reduce health disparities. We propose to address this gap by studying a natural experiment in a high-poverty urban community. The city of Los Angeles is redeveloping Jordan Downs, an obsolete 700-unit public housing project. Over 5 years, the redevelopment will build–(1) 700 new units for existing residents, (2) 700 units for new mixed-income housing residents that will alter the social environment, (3) a new community center with a gymnasium, (4) retail space that will offer healthy eating opportunities, (5) green space that will increase opportunities for physical activity, and (6) additional built environment enhancements that will promote physical activity and healthy eating (e.g. walking and bike lanes, street lighting). Our goal is to study the effect of these improvements on Jordan Downs' residents' body mass index (BMI), overweight and obesity. In Aim 1, we will compare changes in these outcomes for the Jordan Downs residents and a control group (residents of 2 similar public housing projects) for 5 years. In Aim 2, we will disentangle the effects of three major components of the redevelopment: built environment, social environment and new housing. We will do this by taking advantage of the fact that the redevelopment will occur in several phases. In Secondary Aim 3, we will assess why, or why not, the redevelopment affected BMI, overweight and obesity. To do this, we will track physical activity, dietary behavior, and individual- and social mediators. Our data collection will include in-person surveys, 24-hr dietary recalls, and accelerometry. Finally, in Secondary Aim 4 we will explore the moderating effects of sex, race-ethnicity and age. Our study is time- sensitive because the first phase of redevelopment will be complete by Q4 of 2018. Thus, recruitment and baseline data collection must be complete by fall of 2018.