Greenspace in urban areas may have greater protective health effects than elsewhere. Urban dwellers experience more environmental harmful exposures, attentional demands, and stressors than their suburban/rural counterparts.

In this systematic review, we synthesize the results of studies that examined how the greenspace and health relationship varies by urbanicity. We searched for articles in April 2019 that found positive associations between greenspace and physical health. Included articles tested for effect modification by urbanicity among one or more (of eight total) outcomes relevant to health and environmental equity. We coded results as 1 = stronger association in more urban areas, −1 = stronger association in less urban areas, or 0 = no difference.

We found 57 analyses in 37 articles that met our inclusion criteria. Among these analyses, 50.9% showed no difference, 38.6% showed a stronger association for more urban areas, and 10.5% showed a stronger association for less urban areas. More urban areas had stronger associations for cardiovascular-related, birth, and mortality outcomes and for greenspace measured within 500 m.

Stronger greenspace-health associations in more urban areas might be explained in part by the mechanistic pathways underlying these associations. Greenspace can reduce harms from environmental exposures (i.e., air pollution, noise, heat, and artificial light at night) in addition to alleviating attentional demands, reducing chronic stressors, and promoting healthy behavior - factors which might be more necessary, prevalent, or stronger in urban areas. These potential explanations warrant further investigation.

The findings of this review inform public health policy and planning professionals who are attempting to make cities livable for all residents.

城市地区的绿地可能比其他地方具有更大的保护性健康影响。城市居民比郊区/农村居民经历更多的环境有害暴露、注意力需求和压力源。

在这篇系统综述中，我们综合了研究绿色空间和健康关系如何因城市化而变化的研究结果。我们在 2019 年 4 月搜索了发现绿色空间与身体健康之间存在正相关关系的文章。包括测试城市化对与健康和环境公平相关的一项或多项（共八项）结果的影响修改的文章。我们将结果编码为 1 = 在更多城市地区更强的关联，-1 = 在更少城市地区更强的关联，或 0 = 没有差异。

我们在 37 篇文章中发现了 57 项分析符合我们的纳入标准。在这些分析中，50.9% 显示没有差异，38.6% 显示更多城市地区的关联更强，10.5% 显示更少城市地区的关联更强。更多的城市地区与心血管相关、出生和死亡率结果以及 500 m 内测量的绿地有更强的关联。

更多城市地区更强的绿色空间-健康关联可能部分是由这些关联背后的机制途径来解释的。除了减轻注意力需求、减少慢性压力源和促进健康行为之外，绿色空间还可以减少环境暴露（即空气污染、噪音、热量和夜间人造光）造成的危害——这些因素可能更必要、更普遍或更强大在城市地区。这些潜在的解释值得进一步调查。

本次审查的结果为公共卫生政策和规划专业人士提供了信息，他们正在努力使城市适合所有居民。