Ogilvie David, Mitchell Richard, Mutrie Nanette, Petticrew Mark, Platt Stephen
Medical Research Council Social and Public Health Sciences Unit, Glasgow, Scotland.
Am J Prev Med. 2006 Aug;31(2):118-26. doi: 10.1016/j.amepre.2006.03.030.
There is little evidence about the effects of environmental interventions on population levels of physical activity. Major transport projects may promote or discourage physical activity in the form of walking and cycling, but researching the health effects of such "natural experiments" in transport policy or infrastructure is challenging.
Case study of attempts in 2004-2005 to evaluate the effects of two major transport projects in Scotland: an urban congestion charging scheme in Edinburgh, and a new urban motorway (freeway) in Glasgow.
These interventions are typical of many major transport projects. They are unique to their context. They cannot easily be separated from the other components of the wider policies within which they occur. When, where, and how they are implemented are political decisions over which researchers have no control. Baseline data collection required for longitudinal studies may need to be planned before the intervention is certain to take place. There is no simple way of defining a population or area exposed to the intervention or of defining control groups. Changes in quantitative measures of health-related behavior may be difficult to detect.
Major transport projects have clear potential to influence population health, but it is difficult to define the interventions, categorize exposure, or measure outcomes in ways that are likely to be seen as credible in the field of public health intervention research. A final study design is proposed in which multiple methods and spatial levels of analysis are combined in a longitudinal quasi-experimental study.
关于环境干预对人群身体活动水平的影响，证据很少。大型交通项目可能会促进或抑制步行和骑自行车等形式的身体活动，但研究此类交通政策或基础设施方面“自然实验”的健康影响具有挑战性。
对2004 - 2005年在苏格兰评估两个大型交通项目影响的尝试进行案例研究：爱丁堡的城市拥堵收费计划和格拉斯哥的一条新城市高速公路（快车道）。
这些干预措施是许多大型交通项目的典型代表。它们因具体情况而异。它们不能轻易地与它们所处的更广泛政策的其他组成部分分开。它们的实施时间、地点和方式是研究人员无法控制的政治决策。纵向研究所需的基线数据收集可能需要在干预确定实施之前就进行规划。没有简单的方法来界定受干预影响的人群或区域，也没有办法界定对照组。与健康相关行为的定量测量变化可能难以检测到。
大型交通项目显然有影响人群健康的潜力，但难以以公共卫生干预研究领域可能被视为可信的方式界定干预措施、对暴露情况进行分类或测量结果。本文提出了一种最终研究设计，即在纵向准实验研究中结合多种方法和不同空间层面的分析。
