A systematic review of quantitative studies on the impact of blue space on urban human health

Blue spaces are an integral part of cities. This review of 43 articles found a positive association between urban blue spaces and health, with particularly strong evidence for positive associations with reduced premature mortality and obesity, and better self-reported mental health and wellbeing.

1 Introduction
Blue spaces are an integral part of cities. There are an increasing number of quantitative research studies that have explored the salutogenic benefits of blue space in urban contexts and a review is required.

2 Methods
This review followed Cochrane and PRISMA guidelines. Seven databases (PubMed, CINAHL, PsychINFO, Scopus, Science Direct, Web of Science and MEDLINE) were searched for quantitative studies from inception until 1 August 2019 using keywords and MeSH terms. Two reviewers independently screened
articles and appraised their quality using a tool developed by Gascon et al. [1].

3 Results
From 4493 screened citations, 43 studies were included. Eligible articles were published between 2003 and 2019. Quality appraisal rated the majority of studies as ‘Excellent’ (N = 7) or ‘Good’ (N = 24). Although synthesis proved challenging due to methodological and results heterogeneity, a positive
association was found between urban blue spaces and health, with particularly strong evidence found for positive associations with reduced premature mortality and obesity, and better self-reported mental health and wellbeing.

4 Conclusion
Although evidence is growing within the field of urban blue health, the findings are heterogeneous. While standardisation in the way blue space and health outcomes are measured will improve consistency within the field, the positive associations reported to date in several areas of importance to health are promising, irrespective of confounding factors. Further research is required to harness the benefits of urban blue spaces for public health and guide blue space development. In particular, research should aim to understand the mechanisms which exist between urban blue space and health as well as how to maximise exposure to these spaces. It would also be worthwhile to explore further the impacts of smaller urban water features that may also provide benefits.