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

描述(申请人提供)：大多数美国成年人无法获得足够的体力活动，尽管更多的运动对健康有很多好处。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，越来越感兴趣，也越来越多的证据受到横断面设计的阻碍，这些设计限制了得出因果推理的能力。本研究利用交通环境即将发生的显著变化、南金县(西雅图地区)引入轻轨交通(LRT)以及轻轨车站周围社区建筑环境可能发生的变化，以更好地了解建成环境对与交通相关的步行和整体体力活动的因果影响。采用病例对照纵向面板对照设计，对1000名居住在轻轨车站附近(半径1英里以内)或远离(对照)轻轨车站的成年人进行评估，这些成年人在人口统计学和初始社区建筑环境方面相似，将在轻轨服务引入前(基线)、后不久(POST 1)和超过2年(POST 2)进行评估。根据假设，居住在轻铁附近的居民在短期和长期内，与居住在较远的居民相比，与交通相关的步行(例如，从家到轻铁站往返工作)和总的体力活动都会增加。短期的增长可能仅限于轻便铁路的使用者，但据推测，交通步行和总体力活动的长期增长将是由于轻便铁路的使用和促进步行的轻铁站周围建筑环境的变化造成的。这些变化将包括增加居住密度、土地使用组合和零售通道以及行人基础设施。个人的交通工具步行将通过7天的旅行日记和通过加速度计评估的体力活动进行评估。社区建成环境及其变化将通过宗地级土地利用评价进行评估。此外，亦会考虑更改现有的非轻便铁路运输基础设施(例如巴士路线)和是否有足够的服务。在交通资源和建筑环境预期显著变化的一段时间内，对相同个人的交通方式和体力活动的变化进行前瞻性评估，是一种罕见但有力的环境对健康行为影响的测试。需要这样的评估来推动积极的生活研究领域，更重要的是，为了更好地向决策者通报交通系统和建筑环境变化的后果。公共卫生相关性：拟议项目对公共卫生政策和研究具有重要意义，对以下方面的健康影响具有影响 美国日益增长的公共交通系统以及对建筑环境和体力活动领域的更广泛影响。这种能够更好地从建成环境对交通相关和总体体力活动的影响中得出因果推断的能力，对于告知建成环境修改是否可以引起这种必要的健康行为变化至关重要，因此对于告知公共卫生政策是至关重要的。

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.