The effect of light rail transit on physical activity: a natural experiment

描述（由申请人提供）：尽管多运动对健康有很多好处，但大多数美国成年人没有获得足够的身体活动。人们对影响身体活动的环境因素（如社区设计和交通基础设施）的兴趣和证据日益增长，但这些研究却受到截面设计的阻碍，这种设计限制了得出因果推理的能力。本研究利用了交通环境即将发生的显著变化，即在南金县（西雅图地区）引入轻轨交通（LRT），以及LRT站点周围社区建筑环境的可能变化，以更好地了解建筑环境对交通相关步行和整体身体活动的因果影响。使用病例对照纵向面板控制设计，将对1000名居住在LRT站点附近（1英里半径内；病例）或远离（对照）的成年人进行评估，这些成年人在人口统计学上相似，并且在最初的社区建成环境中，将在引入LRT服务之前（基线），之后不久（第1阶段）和超过2年后（第2阶段）进行评估。假设居住在轻轨附近的居民在短期和长期内相对于居住在较远的居民而言，与交通相关的步行（例如，从家、工作到轻轨站）和总体力活动都会增加。短期内的增加可能仅限于轻轨使用者，但据推测，长期的交通步行和总体力活动的增加将源于轻轨的使用和轻轨站点周围促进步行的建成环境的变化。这些变化将包括增加住宅密度、土地使用组合和零售通道，以及行人基础设施。个人的交通步行将通过7天旅行日记进行评估，身体活动将通过加速度计进行评估。小区建设环境及其变化将通过地块级土地利用评估进行评估。此外，亦会考虑现有非轻铁交通基础设施（例如巴士路线）的改变及可用性。在交通资源和建成环境发生显著变化的一段时间内，对同一个人的交通方式和身体活动的变化进行前瞻性评估是一项罕见的、但有效的环境对健康行为影响的测试。需要这样的评价来推进积极生活研究领域，更重要的是，使决策者更好地了解交通系统和建筑环境变化的后果。公共卫生相关性：拟议的项目对公共卫生政策和研究具有重要意义，对健康产生影响

DESCRIPTION (provided by applicant): The majority of U.S. adults fail to obtain adequate physical activity, despite the numerous health benefits associated with being more active. Growing interest in and evidence regarding the environmental factors that affect physical activity, such as neighborhood design and transportation infrastructure, has been hampered by cross-sectional designs that limit the ability to draw causal inference. The present study takes advantage of an upcoming marked change in the transportation environment, the introduction of light rail transit (LRT) in south King County (Seattle area) and likely changes in the neighborhood built environment around LRT stations, to better understand the causal effects of built environment on transportation-related walking and overall physical activity. Using a case-control longitudinal panel controlled design, 1000 adults living either close to (within 1 mile radius; case) or far from (control) an LRT station who are similar demographically and in initial neighborhood built environment, will be assessed prior to (baseline), soon after (post 1), and more than 2 years after (post 2) the introduction of LRT service. It is hypothesized that residents living close to LRT will have an increase in transportation-related walking (e.g., to/from LRT stations from home, work) and total physical activity relative to residents living farther away in both the short- and long-term. The short-term increases will likely be confined to LRT users, but it is hypothesized that long-term increases in transport walking and total physical activity will result from LRT use and changes in the built environment around LRT stations that promote walking. Such changes would include increases in residential density, land use mix and retail access, and pedestrian infrastructure. Individuals' transport walking will be assessed via 7-day travel diaries and physical activity assessed via accelerometry. Neighborhood built environment and changes therein will be assessed via parcel-level land use evaluation. In addition, changes in existing non-LRT transportation infrastructure (e.g., bus routes) and availability will also be considered. The prospective evaluation of changes in the same individuals' transport modes and physical activity over a period of expected marked change in transportation resources and built environment is a rare, but potent test of the impact environment can have on health behaviors. Such evaluations are needed to move forward the field of active living research and more importantly to better inform policy makers regarding consequences of changes in transportation systems and the built environment. PUBLIC HEALTH RELEVANCE: The proposed project has significance for public health policy and research, with health impact implications for the growing public transportation system in the U.S. and broader implications for the field of built environment and physical activity. This ability to better draw causal inference from the impact of built environment on transportation-related and total physical activity is critical to informing whether built environment modification can evoke such needed health behavior changes and is therefore essential to informing public health policy.