Effects of the Built Environment, Crime & Food Prices on BMI, Activity & Eating

描述（由申请人提供）：美国最大的公共卫生挑战之一是肥胖的流行。环境与身体活动、饮食行为以及（在较小程度上）肥胖之间的联系最近得到了支持。虽然这些关联可能代表了一种因果关系，但之前的研究并没有充分排除几种可能的替代解释。例如，一个重视并喜欢步行的人更有可能搬到适合步行的社区；因此，邻里关系的影响很可能与个人属性相混淆。向公平住房机会转移示范项目（MTO）为研究社区特征对肥胖、体育活动和水果/蔬菜摄入量的作用提供了一个很好的环境。MTO的目标是确定搬到“较好”社区的人是否比没有搬到的同类人在教育、经济和健康等各种结果方面有所改善。为了确保在相似的人之间进行比较，家庭被随机分配到三个组中的一个：实验组（他们被要求搬到人口普查区，其中不到10%的人生活在贫困中），第8节组和对照组。MTO数据的主要优势是参与者被随机分为治疗组和对照组，这可能会消除这些组之间的基线差异。由于许多减肥干预措施失败，MTO研究的一个重要发现是，实验组的成年参与者（N=3526）在随机分组后4至7年的BMI明显低于对照组。此外，实验组的人吃水果和蔬菜的频率更高，而第8节实验组的人运动的频率也高于对照组。因此，我们研究的目的是检验在不同研究组中看到的这些结果的差异是否由参与者的环境属性介导。换句话说，我们将检查实验组中的人是否更有可能暴露在支持性环境中，以及环境特征的差异是否解释了治疗（即随机化）效果。本研究将MTO中期评估数据与参与者所在社区的环境特征联系起来。MTO中期评估包括关于健康结果的信息，包括身体质量指数、身体活动水平、水果和蔬菜的消费以及人口统计信息。将收集并与中期评估相关联的环境特征包括：食品供应、食品价格、商业和公共可获得的体育活动资源、城市赞助的娱乐中心、街道连通性、土地使用、居住密度、犯罪统计和人口普查数据。

DESCRIPTION (provided by applicant): One of the greatest public health challenges in the US is the epidemic of obesity. Support for an association between the environment and physical activity, eating behavior and, to a lesser extent, obesity has been recently documented. While these associations may represent a causal relationship, there are several possible alternative explanations that previous research has not adequately ruled out. For example, a person that values and enjoys walking is more likely to move to a walkable neighborhood; so the effect of neighborhood is likely confounded with individual attributes. The Moving to Opportunity for Fair Housing Demonstration (MTO) provides an excellent setting to examine the role of neighborhood characteristics on obesity, physical activity and fruit/vegetable intake. The goal of MTO was to determine whether persons who moved to "better" neighborhoods would experience improvements in a variety of outcomes such as education, economic and health compared to similar persons who did not move. To ensure that comparisons were made between similar persons, families were randomly assigned to one of three groups: the experimental group (who were required to move to census tracts where less than 10% of persons lived in poverty), the Section 8 group and the control group. The key advantage of the MTO data is participants were randomized to treatment and control groups, which would likely eliminate any baseline differences among these groups. Since many weight loss interventions fail, an important finding of the MTO study was that adult participants (N=3526) in the experimental group had a significantly lower BMI 4 to 7 years after randomization compared to controls. Additionally, those in the experimental group had a higher frequency of fruit and vegetable consumption and those in the Section 8 experimental group had a greater frequency of physical activity relative to controls. Thus the purpose of our research is to examine whether the differences in these outcomes seen across study groups were mediated by attributes of the participant's environment. In other words, we will examine whether those in the experimental groups were more likely to be exposed to supportive environments, and whether differences in environmental characteristics explain the treatment (i.e., randomization) effect. This study will link MTO Interim Evaluation data with environmental characteristics of participant's neighborhoods. The MTO Interim Evaluation included information on health outcomes including BMI, physical activity levels and consumption of fruit and vegetables along with demographic information. Environmental characteristics that will be collected and linked with the Interim Evaluation include: food availability, food prices, commercially and publicly available physical activity resources, city-sponsored recreation centers, connectivity of streets, land use, residential density, crime statistics and census data. PUBLIC HEALTH RELEVANCE: The relevance of this research to public health is threefold. It will provide perhaps the best evidence to date on whether environmental attributes are causally related to obesity levels, physical activity and fruit and vegetable consumption at the individual level; it will provide information to inform policy makers on how to better spend public housing financial resources to reduce the burden of obesity in this population; and it will suggest whether built environment changes are a cost effective strategy to reduce the epidemic of obesity.