Benton Jack S, Anderson Jamie, Hunter Ruth F, French David P
School of Psychological Sciences, University of Manchester, Coupland 1 Building, Oxford Road, Manchester, M13 9PL, UK.
Department of Architecture, University of Cambridge, Cambridge, UK.
Int J Behav Nutr Phys Act. 2016 Oct 7;13(1):107. doi: 10.1186/s12966-016-0433-3.
Evidence regarding the association of the built environment with physical activity is influencing policy recommendations that advocate changing the built environment to increase population-level physical activity. However, to date there has been no rigorous appraisal of the quality of the evidence on the effects of changing the built environment. The aim of this review was to conduct a thorough quantitative appraisal of the risk of bias present in those natural experiments with the strongest experimental designs for assessing the causal effects of the built environment on physical activity.
Eligible studies had to evaluate the effects of changing the built environment on physical activity, include at least one measurement before and one measurement of physical activity after changes in the environment, and have at least one intervention site and non-intervention comparison site. Given the large number of systematic reviews in this area, studies were identified from three exemplar systematic reviews; these were published in the past five years and were selected to provide a range of different built environment interventions. The risk of bias in these studies was analysed using the Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions (ACROBAT-NRSI).
Twelve eligible natural experiments were identified. Risk of bias assessments were conducted for each physical activity outcome from all studies, resulting in a total of fifteen outcomes being analysed. Intervention sites included parks, urban greenways/trails, bicycle lanes, paths, vacant lots, and a senior citizen's centre. All outcomes had an overall critical (n = 12) or serious (n = 3) risk of bias. Domains with the highest risk of bias were confounding (due to inadequate control sites and poor control of confounding variables), measurement of outcomes, and selection of the reported result.
The present review focused on the strongest natural experiments conducted to date. Given this, the failure of existing studies to adequately control for potential sources of bias highlights the need for more rigorous research to underpin policy recommendations for changing the built environment to increase physical activity. Suggestions are proposed for how future natural experiments in this area can be improved.
有关建筑环境与身体活动之间关联的证据正在影响政策建议，这些建议主张改变建筑环境以提高人群层面的身体活动水平。然而，迄今为止，尚未对改变建筑环境所产生影响的证据质量进行严格评估。本综述的目的是对那些具有最强实验设计的自然实验中存在的偏倚风险进行全面定量评估，这些实验用于评估建筑环境对身体活动的因果效应。
符合条件的研究必须评估改变建筑环境对身体活动的影响，包括环境变化前至少一次身体活动测量以及变化后至少一次身体活动测量，并且至少有一个干预地点和非干预对照地点。鉴于该领域有大量的系统评价，研究是从三篇典型的系统评价中识别出来的；这些评价发表于过去五年，被选来提供一系列不同的建筑环境干预措施。使用Cochrane干预非随机研究偏倚风险评估工具（ACROBAT-NRSI）分析这些研究中的偏倚风险。
确定了12项符合条件的自然实验。对所有研究的每个身体活动结果进行偏倚风险评估，总共分析了15个结果。干预地点包括公园、城市绿道/小径、自行车道、小路、空地和一个老年人中心。所有结果总体上都存在关键（n = 12）或严重（n = 3）的偏倚风险。偏倚风险最高的领域是混杂因素（由于对照地点不足以及对混杂变量控制不佳）、结果测量和报告结果的选择。
本综述聚焦于迄今为止进行的最强有力的自然实验。鉴于此，现有研究未能充分控制潜在的偏倚来源，这凸显了需要更严格的研究来为改变建筑环境以增加身体活动的政策建议提供依据。针对该领域未来自然实验如何改进提出了建议。
