The following citations are of recent literature that show the benefits of nature or green space on human health and interactions. From mental health, to obesity rates, to pre- and post-natal health, to crime rates – the nearness of nature promotes positive outcomes in many aspects of human life. As the following papers show, application of nature does not necessarily need to be done in a directly therapeutic model. Scroll through the paper abstracts, use the citations to find the full articles, and be inspired to access nature and green space in your life and help others do the same.
Barton J, Pretty J (2010) What is the best dose of nature and green exercise for improving mental health? A multi-study analysis. Environmental science & technology 44:3947-3955
Green exercise is activity in the presence of nature. Evidence shows it leads to positive short and long-term health outcomes. This multistudy analysis assessed the best regime of dose(s) of acute exposure to green exercise required to improve self-esteem and mood (indicators of mental health). The research used meta-analysis methodology to analyze 10 UK studies involving 1252 participants. Outcomes were identified through a priori subgroup analyses, and dose−responses were assessed for exercise intensity and exposure duration. Other subgroup analyses included gender, age group, starting health status, and type of habitat. The overall effect size for improved self-esteem was d = 0.46 (CI 0.34−0.59, p < 0.00001) and for mood d = 0.54 (CI 0.38−0.69, p < 0.00001). Dose responses for both intensity and duration showed large benefits from short engagements in green exercise, and then diminishing but still positive returns. Every green environment improved both self-esteem and mood; the presence of water generated greater effects. Both men and women had similar improvements in self-esteem after green exercise, though men showed a difference for mood. Age groups: for self-esteem, the greatest change was in the youngest, with diminishing effects with age; for mood, the least change was in the young and old. The mentally ill had one of the greatest self-esteem improvements. This study confirms that the environment provides an important health service.
Bell JF, Wilson JS, Liu GC (2008) Neighborhood greenness and 2-year changes in body mass index of children and youth. American J. Preventive Medicine 35:547-553
Background: Available studies of the built environment and the BMI of children and youth suggest a contemporaneous association with neighborhood greenness in neighborhoods with high population density. The current study tests whether greenness and residential density are independently associated with 2-year changes in the BMI of children and youth.
Methods: The sample included children and youth aged 3–16 years who lived at the same address for 24 consecutive months and received well-child care from a Marion County IN clinic network within the years 1996–2002 (n3831). Multiple linear regression was used to examine associations among age- and gender-speciﬁc BMI z-scores in Year 2, residential density, and a satellite-derived measure of greenness, controlling for baseline BMI z-scores and other covariates. Logistic regression was used to model associations between an indicator of BMI z-score increase from baseline to Time 2 and the above-mentioned predictors.
Results: Higher greenness was signiﬁcantly associated with lower BMI z-scores at Time 2 regardless of residential density characteristics. Higher residential density was not associated with Time 2 BMI z-scores in models regardless of greenness. Higher greenness was also associated with lower odds of children’s and youth’s increasing their BMI z-scores over 2 years (OR0.87; 95% CI0.79, 0.97).
Conclusions: Greenness may present a target for environmental approaches to preventing child obesity.Children and youth living in greener neighborhoods had lower BMI z-scores at Time 2, presumably due to increased physical activity or time spent outdoors. Conceptualizations of walkability from adult studies, based solely on residential density, may not be relevant to children and youth in urban environments.
Berman MG, Kross E, Krpan KM, Askren MK, Burson A, Deldin PJ, Kaplan S, Sherdell L, Gotlib IH, Jonides J (2010) Interacting with nature improves cognition and affect for individuals with depression. J. Affective Disorders 140:300-305
Background: This study aimed to explore whether walking in nature may be beneficial for individuals with major depressive disorder (MDD). Healthy adults demonstrate significant cognitive gains after nature walks, but it was unclear whether those same benefits would be achieved in a depressed sample as walking alone in nature might induce rumination, thereby worsening memory and mood.
Methods: Twenty individuals diagnosed with MDD participated in this study. At baseline, mood and short term memory span were assessed using the PANAS and the backwards digit span (BDS) task, respectively. Participants were then asked to think about an unresolved negative autobiographical event to prime rumination, prior to taking a 50-min walk in either a natural or urban setting. After the walk, mood and short-term memory span were reassessed. The following week, participants returned to the lab and repeated the entire procedure, but walked in the location not visited in the first session (i.e., a counterbalanced within-subjects design).
Results: Participants exhibited significant increases in memory span after the nature walk relative to the urban walk, p<.001, ηp2=.53 (a large effect-size). Participants also showed increases in mood, but the mood effects did not correlate with the memory effects, suggesting separable mechanisms and replicating previous work.
Limitations: Sample size and participants’ motivation.
Conclusions: These findings extend earlier work demonstrating the cognitive and affective benefits of interacting with nature to individuals with MDD. Therefore, interacting with nature may be useful clinically as a supplement to existing treatments for MDD.
Dadvand P, de Nazelle A, Figueras F, Basagaña X, Su J, Amoly E, Jerrett M, Vrijheid M, Sunyer J, Nieuwenhuijsen MJ (2012) Green space, health inequality and pregnancy. Environment International 40:110-115
Green spaces have been suggested to improve physical and mental health and well-being by increasing physical activity, reducing air pollution, noise, and ambient temperature, increasing social contacts and relieving psychophysiological stress. Although these mechanisms also suggest potential beneficial effects of green spaces on pregnancy outcomes, to our knowledge there is no available epidemiological evidence on this impact. We investigated the effects of surrounding greenness and proximity to major green spaces on birth weight and gestational age at delivery and described the effect of socioeconomic position (SEP) on these relationships. This study was based on a cohort of births (N = 8246) that occurred in a major university hospital in Barcelona, Spain, during 2001–2005. We determined surrounding greenness from satellite retrievals as the average of Normalized Difference Vegetation Index (NDVI) in a buffer of 100 m around each maternal place of residence. To address proximity to major green spaces, a binary variable was used to indicate whether maternal residential address is situated within a buffer of 500 m from boundaries of a major green space. For each indicator of green exposure, linear regression models were constructed to estimate change in outcomes adjusted for relevant covariates including individual and area level SEP. None of the indicators of green exposure was associated with birth weight and gestational age. After assessing effect modification based on the level of maternal education, we detected an increase in birth weight (grams) among the lowest education level group (N = 164) who had higher surrounding NDVI (Regression coefficient (95% confidence interval (CI) of 436.3 (43.1, 829.5)) or lived close to a major green space (Regression coefficient (95% CI)) of 189.8 (23.9, 355.7)). Our findings suggest a beneficial effect of exposure to green spaces on birth weight only in the lowest SEP group.
Donovan GH, Michael YL, Butry DT, Sullivan AD, Chase JM (2011) Urban trees and the risk of poor birth outcomes. Health & Place 17:390-393
This paper investigated whether greater tree-canopy cover is associated with reduced risk of poor birth outcomes in Portland, Oregon. Residential addresses were geocoded and linked to classified-aerial imagery to calculate tree-canopy cover in 50, 100, and 200 m buffers around each home in our sample (n=5696). Detailed data on maternal characteristics and additional neighborhood variables were obtained from birth certificates and tax records. We found that a 10% increase in tree-canopy cover within 50 m of a house reduced the number of small for gestational age births by 1.42 per 1000 births (95% CI—0.11–2.72). Results suggest that the natural environment may affect pregnancy outcomes and should be evaluated in future research.
Gandelman N, Piani G, Ferre Z (2012) Neighborhood determinants of quality of life. J Happiness Studies 13:547-563
In this paper we analyze various dimensions of the quality of life in Uruguay. The results suggest that differences in overall happiness and in domain satisfaction can partly be explained by different levels of access to public goods. We find that the monetary equivalent value of public goods such as electricity, running water, sewage system, drainage, waste disposal system, street lighting, sidewalks in good condition, trees in the street, and the absence of air or noise pollution is considerable.
Keywords: Public goods, Neighborhood amenities, Quality of life
Lachowycz K, Jones AP (2011) Greenspace and obesity: a systematic review of the evidence. Obesity Reviews 12:e183-e189
Open-access available at: http://onlinelibrary.wiley.com/doi/10.1111/j.1467-789X.2010.00827.x/full
Greenspace is theoretically a valuable resource for physical activity and hence has potential to contribute to reducing obesity and improving health. This paper reports on a systematic review of quantitative research examining the association between objectively measured access to greenspace and (i) Physical activity, (ii) Weight status and (iii) Health conditions related to elevated weight. Literature searches were conducted in SCOPUS, Medline, Embase and PYSCHINFO. Sixty studies met the inclusion criteria and were assessed for methodological quality and strength of the evidence. The majority (68%) of papers found a positive or weak association between greenspace and obesity-related health indicators, but findings were inconsistent and mixed across studies. Several studies found the relationship varied by factors such as age, socioeconomic status and greenspace measure. Developing a theoretical framework which considers the correlates and interactions between different types of greenspace and health would help study design and interpretation of reported findings, as would improvement in quality and consistency of greenspace access measures. Key areas for future research include investigating if and how people actually use greenspace and improving understanding of the mechanisms through which greenspace can improve health and, in particular, if physical activity is one such mechanism.
Mitchell R, Popham F (2008) Effect of exposure to natural environment on health inequalities: an observational population study. Lancet 372:1655-1660
Studies have shown that exposure to the natural environment, or so-called green space, has an independent effect on health and health-related behaviours. We postulated that income-related inequality in health would be less pronounced in populations with greater exposure to green space, since access to such areas can modify pathways through which low socioeconomic position can lead to disease. We classified the population of England at younger than retirement age (n=40813236) into groups on the basis of income deprivation and exposure to green space. We obtained individual mortality records (n=366348) to establish whether the association between income deprivation, all-cause mortality, and cause-specific mortality (circulatory disease, lung cancer; and intentional self-harm) in 2001-05, varied by exposure to green space measured in 2001, with control for potential confounding factors. We used stratified models to identify the nature of this variation. The association between income deprivation and mortality differed significantly across the groups of exposure to green space for mortality from all causes (p<0.0001) and circulatory disease (p=0.0212), but not from lung cancer or intentional self-harm. Health inequalities related to income deprivation in all-cause mortality and mortality from circulatory diseases were lower in populations living in the greenest areas. The incidence rate ratio (IRR) for all-cause mortality for the most income deprived quartile compared with the least deprived was 1.93 (95% CI 1.86-2.01) in the least green areas, whereas it was 1.43 (1.34-1.53) in the most green. For circulatory diseases, the IRR was 2.19 (2.04-2.34) in the least green areas and 1.54 (1.38-1.73) in the most green. There was no effect for causes of death unlikely to be affected by green space, such as lung cancer and intentional self-harm. Populations that are exposed to the greenest environments also have lowest lewis of health inequality related to income deprivation. Physical environments that promote good health might be important to reduce socioeconomic health inequalities.
Troy A, Grove JM, O’Neil-Dunne J (2012) The relationship between tree canopy and crime rates across an urban–rural gradient in the greater Baltimore region. Landscape and Urban Planning 106:262-270
The extent to which urban tree cover influences crime is in debate in the literature. This research took advantage of geocoded crime point data and high resolution tree canopy data to address this question in Baltimore City and County, MD, an area that includes a significant urban–rural gradient. Using ordinary least squares and spatially adjusted regression and controlling for numerous potential confounders, we found that there is a strong inverse relationship between tree canopy and our index of robbery, burglary, theft and shooting. The more conservative spatially adjusted model indicated that a 10% increase in tree canopy was associated with a roughly 12% decrease in crime. When we broke down tree cover by public and private ownership for the spatial model, we found that the inverse relationship continued in both contexts, but the magnitude was 40% greater for public than for private lands. We also used geographically weighted regression to identify spatial non-stationarity in this relationship, which we found for trees in general and trees on private land, but not for trees on public land. Geographic plots of pseudo-t statistics indicated that while there was a negative relationship between crime and trees in the vast majority of block groups of the study area, there were a few patches where the opposite relationship was true, particularly in a part of Baltimore City where there is an extensive interface between industrial and residential properties. It is possible that in this area a significant proportion of trees is growing in abandoned lands between these two land uses.