Policy Standards for Healthy Built Environments: A Systematic Review of Health Impact Assessments and Nonrandomized Evaluations of Implemented Policies.

The use of policy standards for the built environment is increasingly explored, yet evidence on their health impact is limited. This systematic review assesses the impact and projected effects of built environment policy standards on health, alongside factors influencing observed changes and lessons learned. We conducted a comprehensive search across 11 databases for studies published between 1990 and 2024 evaluating policy standards targeting the domains of publicly accessible urban green space (UGS), transportation, or food environment in upper-middle- and high-income countries and reporting a health-related outcomes. Prospective modeling and retrospective studies with before and after or comparison groups were eligible. Data extraction covered mortality, morbidity, health determinants, unanticipated findings and reported implementation lessons. Risk-of-bias assessment employed the ROBINS-I and PROBAST tools as well as an additional quality appraisal for HIAs. Of 11,247 records screened, 27 studies were included. Health Impact Assessments (HIAs) on UGS policy standards estimated, among other outcomes, up to 25 fewer projected deaths/100,000; one HIA on superblocks (mixed domains) projected twice that number. A HIA on a transport standard projected 3.1% less cardiovascular morbidity. In evaluations of applied policy standards, a transport intervention was associated with more walking. Two of three applied food stocking studies were associated with increased healthy food sales. In mixed-domain studies, the Liveable Neighborhood Guidelines were associated with increased odds for walking outcomes and sense of community, and studies on 20-minute neighborhoods were associated with increased odds for walking outcomes, but no change in BMI or food-related outcomes. Several applied studies reported unplanned effects such as spillover effects of the intervention to neighboring areas and increased revenues. HIAs highlighted addressing gentrification and ensuring quality of UGS. The wide range of outcomes and methods limited comparability across studies, while the modeling nature of HIAs and the observational design of most applied studies complicated the risk-of-bias assessment and generally resulted in low certainty of evidence. Many applied policy standards were associated with beneficial health behaviors, suggesting applied policy standards can be effective for improving health outcomes. HIAs projected health effects of various extents. However, it remains important to assess potential unintended consequences and evaluate whether policy standards contribute to reducing health inequalities.