Greenspace and human microbiota: A systematic review.

BACKGROUND: Potential effect of greenspace exposure on human microbiota have been explored by a number of observational and interventional studies, but the results remained mixed. We comprehensively synthesized these studies by performing a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. METHODS: Comprehensive literature searches in three international databases (PubMed, Embase, and Web of Science) and three Chinese databases (China National Knowledge Infrastructure, Wanfang, and China Biology Medicine disc) were conducted from inception to November 1, 2023. Observational and interventional studies that evaluated associations between greenspace exposure and human microbiota at different anatomical sites were included. Studies were assessed using the National Toxicology Program's office of Health Assessment and Translation risk of bias tool and certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation framework. Two authors independently performed study selection, data extraction, and risk of bias assessment, and evidence grading. Study results were synthesized descriptively. RESULTS: Twenty studies, including 11 observational studies and 9 interventional studies, were finally included into the systematic review. The microbiota of the included studies was from gut (n = 13), skin (n = 10), oral cavity (n = 5), nasal cavity (n = 5) and eyes (n = 1). The majority of studies reported the associations of greenspace exposure with increased diversity (e.g., richness and Shannon index) and/or altered overall composition of human gut (n = 12) and skin microbiota (n = 8), with increases in the relative abundance of probiotics (e.g., Ruminococcaceae) and decreases in the relative abundance of pathogens (e.g., Streptococcus and Escherichia/Shigella). Due to limited number of studies, evidence concerning greenspace and oral, nasal, and ocular microbiota were still inconclusive. CONCLUSION: The current evidence suggests that greenspace exposure may diversify gut and skin microbiota and alter their composition to healthier profiles. These findings would be helpful in uncovering the potential mechanisms underlying greenspace and human health and in promoting a healthier profile of human microbiota.

Exploring the association between campus environment of higher education and student health: A systematic review of findings and measures.

Numerous studies have investigated the relationship between the neighborhood environments and residents' health. However, other important settings, such as university campuses, have received little attention. This paper conducted a systematic review and synthesized existing empirical works examining the association between the university/college campuses built and natural environments and students' health. Following the PRISMA guidelines, we searched nine databases using keywords related to higher-education campuses and health-related outcomes. A total of 19 articles were identified, including fifteen cross-sectional studies, three experimental studies, and one longitudinal study. The majority of the studies were conducted in Asian countries and published in the past five years. The findings indicate that active transportation infrastructure, such as increased road intersections and better walkability, were found to be positively associated with students' physical activity. The natural environments, including perceived naturalness, blue space, and greenness was shown to support student's mental health and quality of life. Specifically, blue space was found to be the most preferred place for mental restoration, and scattered trees demonstrated a supportive effect in reducing depression symptoms. Even just viewing virtual trees had a restorative effect and feel less anxiety. Additionally, during the summer, tree shadows were identified as the most important factors for enhancing thermal comfort. This review emphasizes the crucial role of campus environments in promoting college students' health. Future longitudinal studies and investigations using multiple campuses would provide a more comprehensive understanding of this relationship. Such endeavors can contribute to the development of evidence-based strategies for designing and planning healthy campus environments that optimize students' well-being.

COVID-19 and campus users: A longitudinal and place-based study of university mobilities in Texas.

The COVID-19 pandemic has disrupted people's daily routines, including travel behaviors, social interactions, and work-related activities. However, the potential impacts of COVID-19 on the use of campus locations in higher education such as libraries, food courts, sports facilities, and other destinations are still unknown. Focusing on three largest universities in Texas (Texas A&M university, the University of Texas at Austin, and Texas Tech University), this study compares changes in campus destination visitations between pre and post COVID-19 outbreak (2019 Fall and 2021 Fall semesters, respectively) using the mobility data from SafeGraph. It also examines the potential moderation effects of walkable distance (i.e. 1 km) and greenery (i.e. NDVI value). The results presented the significant effects of COVID-19 on decreasing visitations to various campus places. The visitation decreased more significantly for people living within 1 km (defined as a walkable distance) of campus and for the food, eating, and drinking places and the sports, recreation, and sightseeing places. This finding suggests that those living near campus (mostly students) decreased their reliance on campus destinations, especially for eating/drinking and recreation purposes. The level of greeneries at/around campus destinations did not moderate campus visitations after COVID-19. Policy implications on campus health and urban planning were discussed.

Contextual and environmental factors that influence health: A within-subjects field experiment protocol.

Background: Despite the growing research on environment-physical activity (PA) relationships, field experimental studies are limited. Such studies offer opportunities to focus on real-world environmental exposure and related PA and health outcomes, allowing researchers to better isolate the causal effect of exposures/interventions. Focusing on the street/pedestrian environment as a routine setting for people's daily activities, this research aims to develop and test a field experiment protocol that integrates instantaneous assessments of the environment, PA, and health outcomes. The protocol involves the use of state-of-the-art environmental monitoring and biosensing techniques and focuses on physically active road users (pedestrians and bicyclists) who are more directly exposed to their surrounding environment than others such as drivers. Methods/Design: An interdisciplinary research team first identified the target measurement domains for the health outcomes (e.g., stress, thermal comfort, PA) and the street-level environmental exposures (e.g., land use, greenery, infrastructure conditions, air quality, weather) guided by the previous literature which was primarily observational. Portable or wearable measurement instruments (e.g., GPS, accelerometer, biosensor, mini camera, smartphone app, weather station, air quality sensor) were identified, pilot tested, and selected for the identified measures. We ensured that these measures are readily linkable using the time stamp and include eye-level exposures as they impact the users' experiences more directly yet missing in most prior studies relying on secondary, aerial-level measures. A 50-min experimental route was then determined to include typical everyday environments in park and mixed-use settings and to engage participants in three common modes of transportation (walking, bicycling, and driving). Finally, a detailed staff protocol was developed, pilot-tested, and used in a 36-participant within-subject field experiment in College Station, TX. The experiment was successfully executed, showing its potential to support future field experiments that can provide more accurate real-time, real-environment, and multi-dimensional information. Discussion: Our study demonstrates the feasibility of capturing the multifold health benefits/harms related to walking and bicycling in varying urban environments by combining field experiments with environmental, behavioral, and physiological sensing. Our study protocol and reflections can be helpful for a broad spectrum of research addressing the complex and multi-level pathways between the environment, behavior, and health outcomes.

Life Course Nature Exposure and Mental Health Outcomes: A Systematic Review and Future Directions.

Recently, an emerging body of literature has examined the relationships between early life nature exposure and mental health in later life; however, no critical synthesis yet exists regarding the extent and strength of these relationships. This study presents the first systematic review of studies in this growing area. Following the PRISMA framework, we searched six databases (i.e., Scopus, Web of Science, MEDLINE, Embase, PsycINFO, and CINAHL); conducted identification, screening, eligibility, and inclusion analyses; and identified a final set of 29 articles. The review set comprises primarily longitudinal studies, with several cross-sectional studies using retrospective measures of childhood nature exposure. The majority of included studies were published between 2016 and 2020 and conducted in Europe and North America. Five domains of mental health outcomes are associated with early-life nature exposure: incidence of mental disorders, psychiatric symptoms and emotions, conduct problems in children, cognitive function, and subjective well-being. The evidence lends support to an overall beneficial role of early nature exposure on mental health, although inconsistencies are reported. Taken together, the evidence does not suggest that exposure at any given life stage is more saliently associated with mental health outcomes than at others. We discuss the validity concerns and methodological remedies and offer directions for future research.