Greenness, Blue Spaces and Human Health: An Updated Umbrella Review of Epidemiological Meta-analyses

We systematically summarizes and evaluates the relationship between green and blue spaces and human health through an umbrella review of epidemiological meta- analyses up to the year 2024. Green spaces have been recognized for their ecological services, including air purification and biodiversity protection, which contribute to the enhancement of life quality and well-being. The review highlights significant advancements in research methodologies and the emergence of new evidence linking green spaces with reduced risks of various health issues, such as type 2 diabetes, obesity, cardiovascular diseases, and improved mental health. The study follows the PRISMA guidelines and includes meta-analyses from PubMed, Embase, and Cochrane databases, focusing on new evidence and methodological improvements. Inclusion criteria encompass studies on human populations, exposure to green and blue spaces, and health outcomes such as mortality, disease risk, and physiological indicators. Data extraction and quality assessment of evidence and methods are conducted using the GRADE system and AMSTAR 2 tool. The review finds that green space exposure is associated with reduced all-cause mortality, cardiovascular disease mortality, incidence of diabetes and metabolic syndrome, low birth weight, and mental health improvements. Blue spaces also show positive associations with health outcomes, including reduced obesity rates and improved psychological well-being. However, the evidence regarding green space exposure and specific health outcomes like cancer, asthma, and allergic rhinitis remains heterogeneous and unclear. The review underscores the need for future research to address methodological limitations, incorporate various green space indicators, and explore the complex mechanisms of human-environment interactions. It concludes by emphasizing the importance of green and blue spaces in urban planning and public health strategies to improve residents health and quality of life.