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 肥胖是一个最大的公共卫生问题，其在弱势群体中的流行率继续上升。 有证据表明，肥胖与社区建设和社会环境特征有关。 这些问题包括可步行、锻炼机会、绿色空间、食品供应和社会凝聚力。但事实并非如此 明确这些特征本身是否会导致肥胖。确定因果关系很重要，需要告知 公共卫生努力缩小健康差距。我们建议通过研究一种自然的 在高度贫困的城市社区进行试验。洛杉矶市正在重新开发乔丹唐斯，一个 淘汰700套公房项目。在五年内，重建计划将兴建-(1)700个新单位，供 现有居民，(2)将改变社会环境的新的混合收入住房居民700套， (3)一个带健身房的新社区中心，(4)提供健康饮食机会的零售空间，(5) 将增加体育活动机会的绿色空间，以及(6)额外的建筑环境 将促进身体活动和健康饮食的增强措施(例如步行和自行车道、街道 照明)。我们的目标是研究这些改进对乔丹唐斯居民身体质量指数的影响 (BMI)、超重和肥胖。在目标1中，我们将比较乔丹唐斯的这些结果的变化 居民和对照组(2个类似的公共房屋项目的居民)为期5年。在目标2中，我们将 拆解重建的三个主要组成部分的影响：建成环境、社会 环境和新住房。我们会利用这项重建计划将会 分几个阶段发生。在次要目标3中，我们将评估重建为什么或为什么不会影响BMI， 超重和肥胖。为了做到这一点，我们将跟踪身体活动、饮食行为以及个人和社会 调解人。我们的数据收集将包括面对面调查、24小时饮食召回和加速测量。最后， 在第二目标4中，我们将探索性别、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，招聘和 基线数据收集必须在2018年秋季之前完成。

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.