Effects of vacant lots on human health: A systematic review of the evidence

Author: Olivia Poole
About the Author: Olivia Poole is a third year at Northwestern University studying social/environmental policy and data science. She is passionate about using environmental policy and science to narrow healthcare disparities, and also very interested in urban agriculture and food sovereignty. 

Research shows a vacant lot is not empty – it holds health risks and benefits.
Published in April 2021, this article aimed to answer the research question: How do poor quality greenspaces (e.g. vacant lots) influence health? While there are some limiting factors to this study and review, they point to opportunities for more research in this field.

After conducting a systematic review, the researchers consolidated the current literature about the effects of vacant lots on human health to summarize findings and identify gaps in the existing body of evidence to suggest future research.

Using PRISMA guidelines – the global standard for systematic and scoping literature reviews – the researchers found 438 articles, which were winnowed to 22; 11 used controlled experimental designs. 

The researchers broke down the results from the selected articles into several categories but did not use a specific coding mechanism/scheme/framework at this point. Subsequently, they split the results into two categories of investigation: health outcomes (like stress) and health risks (like crime). 

The reported health outcomes were stress, mental health, self-reported physical activity, heart rate, homicide rates, and blood lead levels. The reported health risks were crime, gun violence, insect vectors, parasites, heavy metal contamination and injuries.

Among the 11 experimental studies, 73% showed that “greening” of vacant lots improved health; 18% showed some neutral effects; and one study showed a decline in health.

Following the results, the researchers included a section on the limitations they found, to inform readers of potential areas of study. 

The main limitations of the evidence presented in the articles analyzed were the narrow health outcomes investigated, small sample size, the short follow-up times, and the limited geographic scope of the studies.

Overall, however, the article provided an efficient but encompassing review of the current knowledge, as well as the gaps, about how vacant lots, and the greening of them, impact human health. 
Several points are worth noting:  The extensive introduction describes “pathways” – both direct and indirect – by which greenspace exposure could improve health provides valuable information for in diverse stakeholders interested in the health benefits of nature. Further, the need for longitudinal research, mentioned in the “future directions” section, is a call to action for all researchers in the field.
The Journal of Landscape and Urban Planning is one of an increasing number of journals that includes a section on policy implications of article. Including policy implications in more papers would be incredibly useful to those of us working at the intersection of research and policy outcomes.

- Olivia Poole

Source Article: Sivak, C. J., A. L. Pearson and P. Hurlburt (2021). "Effects of vacant lots on human health: A systematic review of the evidence." Landscape and Urban Planning 208: 104020. http://www.sciencedirect.com/science/article/pii/S0169204620315048

---