Lifelong Residential Exposure to Green Space and Attention: A Population-based Prospective Study

How does the macroenvironment influence brain and behaviour-a review of current status and future perspectives

The environment influences brain and mental health, both detrimentally and beneficially. Existing research has emphasised the individual psychosocial 'microenvironment'. Less attention has been paid to 'macroenvironmental' challenges, including climate change, pollution, urbanicity, and socioeconomic disparity. Notably, the implications of climate and pollution on brain and mental health have only recently gained prominence. With the advent of large-scale big-data cohorts and an increasingly dense mapping of macroenvironmental parameters, we are now in a position to characterise the relation between macroenvironment, brain, and behaviour across different geographic and cultural locations globally. This review synthesises findings from recent epidemiological and neuroimaging studies, aiming to provide a comprehensive overview of the existing evidence between the macroenvironment and the structure and functions of the brain, with a particular emphasis on its implications for mental illness. We discuss putative underlying mechanisms and address the most common exposures of the macroenvironment. Finally, we identify critical areas for future research to enhance our understanding of the aetiology of mental illness and to inform effective interventions for healthier environments and mental health promotion.

Associations of residential green space with internalizing and externalizing behavior in early childhood

BACKGROUND

Green space exposures may promote child mental health and well-being across multiple domains and stages of development. The aim of this study was to investigate associations between residential green space exposures and child mental and behavioral health at age 4-6 years.

METHODS

Children's internalizing and externalizing behaviors in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) cohort in Shelby County, Tennessee, were parent-reported on the Child Behavior Checklist (CBCL). We examined three exposures-residential surrounding greenness calculated as the Normalized Difference Vegetation Index (NDVI), tree cover, and park proximity-averaged across the residential history for the year prior to outcome assessment. Linear regression models were adjusted for individual, household, and neighborhood-level confounders across multiple domains. Effect modification by neighborhood socioeconomic conditions was explored using multiplicative interaction terms.

RESULTS

Children were on average 4.2 years (range 3.8-6.0) at outcome assessment. Among CANDLE mothers, 65% self-identified as Black, 29% as White, and 6% as another or multiple races; 41% had at least a college degree. Higher residential surrounding greenness was associated with lower internalizing behavior scores (-0.66 per 0.1 unit higher NDVI; 95% CI: -1.26, -0.07) in fully-adjusted models. The association between tree cover and internalizing behavior was in the hypothesized direction but confidence intervals included the null (-0.29 per 10% higher tree cover; 95% CI: -0.62, 0.04). No associations were observed between park proximity and internalizing behavior. We did not find any associations with externalizing behaviors or the attention problems subscale. Estimates were larger in neighborhoods with lower socioeconomic opportunity, but interaction terms were not statistically significant.

CONCLUSIONS

Our findings add to the accumulating evidence of the importance of residential green space for the prevention of internalizing problems among young children. This research suggests the prioritization of urban green spaces as a resource for child mental health.

Understanding the pathways between the use of urban green spaces and self-rated health: A case study in Mexico City

In recent decades, extensive research has demonstrated the positive impact of urban green spaces (UGS) on public health through several pathways. However, in the context of Latin America, particularly Mexico City, there remains a notable scarcity of evidence linking UGS use to health outcomes and an insufficient understanding of the pathways or factors underlying these associations. Therefore, this study employs Structural Equation Modeling (SEM) to investigate the intricate pathways between UGS use and residents' perceived health in Mexico City, a densely populated urban center. The SEM integrates three key mediators: sentiments towards UGS, UGS quality, and time spent within these spaces. Survey data was collected through an online survey distributed via social media in May 2020 (n = 1,707). The findings indicate a minor yet significant direct link between UGS use and self-reported health (0.0427, p < 0.1). Conversely, the indirect pathways through sentiments towards UGS, UGS quality, and time spent in UGS were highly significant (0.1950, p < 0.01), underscoring their substantial role as mediators in the UGS use-health association. While a comprehensive understanding of the mechanisms linking perceived health to UGS use in Mexico City requires further research, this study proposes that fostering positive sentiments towards UGS, enhancing UGS quality, and encouraging extended visits to green areas could potentially amplify the perceived health benefits associated with UGS use among residents. These insights offer valuable inputs for policymaking, emphasizing the importance of integrating public perspectives to optimize nature-based solutions and broaden their positive impact within Mexico City.

Residential green and blue spaces and working memory in children aged 6-12 years old. Results from the INMA cohort

Availability of green and blue spaces in the area of residence has been related to various health outcomes during childhood, including neurodevelopment. Some studies have shown that children living in greener and/or bluer areas score better on cognitive tasks although the evidence is inconsistent. These protective effects are hypothesized to occur in part through reductions in air pollution exposure and odds of attention-deficit/hyperactivity disorder (ADHD). This study analysed the effects of residential green and blue spaces on working memory of children in the Spanish INfancia y Medio Ambiente (INMA) birth cohort and the potential joint mediating role of air pollution and ADHD. The study samples were composed of 1738 six-to eight-year-olds (M = 7.53, SD = 0.68, 49% female) and 1449 ten-to twelve-year-olds (M = 11.18, SD = 0.69, 50% female) living in Asturias, Gipuzkoa, Sabadell or Valencia, Spain. Individual Normalized Difference Vegetation Index (NDVI) values in 100-, 300- and 500-m buffers and availability of green and blue spaces >5000 m2 in 300-m buffers were calculated using Geographic Information Systems software. Individual NO2 values for the home environment were estimated using ESCAPE's land use regression models. ADHD diagnosis was reported by participants' parents via a questionnaire. Working memory was measured with numbers and colours (in the younger group only) N-back tests (2- and 3-back d'). Mixed-effects models informed of the beneficial effects of NDVI in a 300-m buffer on numerical working memory in the younger sample although the results were not consistent for all d' scores considered and failed to detect significant effects through the candidate mediators. Availability of major blue spaces did not predict working memory performance. Provision of green spaces may play a role in children's working memory but further research is required.

How does the macroenvironment influence brain and behaviour - a review of current status and future perspectives

The environment influences mental health, both detrimentally and beneficially. Current research has emphasized the individual psychosocial 'microenvironment'. Less attention has been paid to 'macro-environmental' challenges including climate change, pollution, urbanicity and socioeconomic disparity. With the advent of large-scale big-data cohorts and an increasingly dense mapping of macroenvironmental parameters, we are now in a position to characterise the relation between macroenvironment, brain, and behaviour across different geographic and cultural locations globally. This review synthesises findings from recent epidemiological and neuroimaging studies, aiming to provide a comprehensive overview of the existing evidence between the macroenvironment and the structure and functions of the brain, with a particular emphasis on its implications for mental illness. We discuss putative underlying mechanisms and address the most common exposures of the macroenvironment. Finally, we identify critical areas for future research to enhance our understanding of the aetiology of mental illness and to inform effective interventions for healthier environments and mental health promotion.

Availability, accessibility, and use of green spaces and cognitive development in primary school children

Green spaces may have beneficial impacts on children's cognition. However, few studies explored the exposure to green spaces beyond residential areas, and their availability, accessibility and uses at the same time. The aim of the present study was to describe patterns of availability, accessibility, and uses of green spaces among primary school children and to explore how these exposure dimensions are associated with cognitive development. Exposures to green space near home, school, commuting route, and other daily activity locations were assessed for 1607 children aged 6-11 years from six birth cohorts across Europe, and included variables related to: availability (NDVI buffers: 100, 300, 500 m), potential accessibility (proximity to a major green space: linear distance; within 300 m), and use (play time in green spaces: hours/year), and the number of visits to green spaces (times/previous week). Cognition measured as fluid intelligence, inattention, and working memory was assessed by computerized tests. We performed multiple linear regression analyses on pooled and imputed data adjusted for individual and area-level confounders. Availability, accessibility, and uses of green spaces showed a social gradient that was unfavorable in more vulnerable socioeconomic groups. NDVI was associated with more playing time in green spaces, but proximity to a major green space was not. Associations between green space exposures and cognitive function outcomes were not statistically significant in our overall study population. Stratification by socioeconomic variables showed that living within 300 m of a major green space was associated with improved working memory only in children in less deprived residential areas (β = 0.30, CI: 0.09,0.51), and that more time playing in green spaces was associated with better working memory only in children of highly educated mothers (β per IQR increase in hour/year = 0.10; 95% CI: 0.01, 0.19). However, studying within 300 m of a major green space increased inattention scores in children in more deprived areas (β = 15.45, 95% CI: 3.50, 27.40).

Diversity of Studies on Neighborhood Greenspace and Brain Health by Racialized/Ethnic Group and Geographic Region: A Rapid Review

Studies examining associations between greenspace and Alzheimer's disease and related dementia (ADRD) outcomes are rapidly on the rise, yet no known literature reviews have summarized the racialized/ethnic group and geographic variation of those published studies. This is a significant gap given the known disparities in both greenspace access and ADRD risk between racialized/ethnic groups and between developed versus developing countries. In this rapid literature review, we (1) describe the diversity of published greenspace-brain health studies with respect to racialized/ethnic groups and geographic regions; (2) determine the extent to which published studies have investigated racialized/ethnic group differences in associations; and (3) review methodological issues surrounding studies of racialized/ethnic group disparities in greenspace and brain health associations. Of the 57 papers meeting our inclusion criteria as of 4 March 2022, 21% (n = 12) explicitly identified and included individuals who were Black, Hispanic/Latinx, and/or Asian. Twenty-one percent of studies (n = 12) were conducted in developing countries (e.g., China, Dominican Republic, Mexico), and 7% (n = 4) examined racialized/ethnic group differences in greenspace-brain health associations. None of the studies were framed by health disparities, social/structural determinants of health, or related frameworks, despite the known differences in both greenspace availability/quality and dementia risk by racialized/ethnic group and geography. Studies are needed in developing countries and that directly investigate racialized/ethnic group disparities in greenspace-brain health associations to target and promote health equity.

Exposure to greenspace and bluespace and cognitive functioning in children - A systematic review

BACKGROUND

The field of greenspace and bluespace research in relation to cognitive outcomes is rapidly growing. Several systematic reviews have already been published on this topic but none of them are specific to cognitive outcomes in the entire age range of children. Moreover, only a few of them have examined the effects of bluespace in addition to greenspace. Also, theses reviews are focused either only on observational studies or experimental studies. Our systematic review focuses on cognitive outcomes in relation to greenspace and bluespace in children and adolescents aged 0-18; it captures both observational and experimental studies. Cognitive outcomes are presented according to an evidence-based taxonomy of human cognitive abilities: the Cattell-Horn-Carroll (CHC) theory.

METHODS

We conducted searches in the PubMed and PsychInfo databases, from their inception dates to 17 December 2021. We used three-text terms related to outcome, exposure, and population as well as MeSH terms for outcome and population. Further, the reference lists and existing reviews were searched ("snowball" search) until 21 April 2022 to detect additional studies. For the results reporting, we followed the updated guidelines of the Preferred Reporting Items for Systematic reviews and Meta Analyses (PRISMA). We included observational and experimental studies on greenspace or bluespace exposure in relation to cognitive functioning, published in English, German, or Polish. Two reviewers independently checked study eligibility and extracted data. Two reviewers evaluated the risk of bias according to the Office of Health Assessment and Translation (OHAT) tool. At all stages, discrepancies between the two reviewers were solved via discussion with a third reviewer.

RESULTS

Records identified from PubMed (n = 2030) and PsycINFO (n = 1168) were deduplicated and screened. Twenty one reports were first selected. The "snowball" search revealed 16 additional reports. Altogether, 39 studies (17 experimental and 22 observational) published in 37 reports were qualified. The data extraction showed that the methodology used in the studies was heterogenous and the findings were inconsistent. The majority of the studies investigated attentional functioning, which we subdivided into two categories according to the CHC theory: attentional control and reaction and decision speed (12 studies) and attentional control and processing speed (10 studies). Eleven studies investigated working memory and/or short-term memory that we categorized as CHC working memory capacity. Nine studies investigated intellectual functioning, which we categorized as CHC general ability, fluid reasoning, and comprehension-knowledge. Two studies investigated visual-spatial skills, which we categorized as CHC visual processing and psychomotor speed. One study measured parent-reported attention; two studies examined early childhood/cognitive development; three studies examined decision-making and self-regulation, which can be categorized as several CHC theory abilities.

DISCUSSION

The heterogeneity of the included studies does not permit clear conclusions for our review. In accordance with previous systematic reviews, greenspace and bluespace were not more strongly related to a particular domain of cognitive functioning than other cognitive domains, and no effects of age or type of exposure assessment on the association between nature and cognition were detected. Further research is needed, including state-of-the-art of assessment of cognitive outcomes and diverse exposure assessment methods within both observational and experimental approaches. Expertise will be required in several domains, such as environmental epidemiology, cognitive psychology, and neuropsychology. Systematic review registration number (INPLASY): 202220018.

Residential green space improves cognitive performances in primary schoolchildren independent of traffic-related air pollution exposure

BACKGROUND

Cognitive performances of schoolchildren have been adversely associated with both recent and chronic exposure to ambient air pollution at the residence. In addition, growing evidence indicates that exposure to green space is associated with a wide range of health benefits. Therefore, we aimed to investigate if surrounding green space at the residence improves cognitive performance of primary schoolchildren while taking into account air pollution exposure.

METHODS

Cognitive performance tests were administered repeatedly to a total of 307 primary schoolchildren aged 9-12y, living in Flanders, Belgium (2012-2014). These tests covered three cognitive domains: attention (Stroop and Continuous Performance Tests), short-term memory (Digit Span Forward and Backward Tests), and visual information processing speed (Digit-Symbol and Pattern Comparison Tests). Green space exposure was estimated within several radii around their current residence (50 m to 2000 m), using a aerial photo-derived high-resolution (1 m²) land cover map. Furthermore, air pollution exposure to PM_2.5 and NO₂ during the year before examination was modelled for the child's residence using a spatial-temporal interpolation method.

RESULTS

An improvement of the children's attention was found with more residential green space exposure independent of traffic-related air pollution. For an interquartile range increment (21%) of green space within 100 m of the residence, a significantly lower mean reaction time was observed independent of NO₂ for both the sustained-selective (-9.74 ms, 95% CI: -16.6 to -2.9 ms, p = 0.006) and the selective attention outcomes (-65.90 ms, 95% CI: -117.0 to -14.8 ms, p = 0.01). Moreover, green space exposure within a large radius (2000 m) around the residence was significantly associated with a better performance in short-term memory (Digit-Span Forward Test) and a higher visual information processing speed (Pattern Comparison Test), taking into account traffic-related exposure. However, all associations were attenuated after taking into account long-term residential PM_2.5 exposure.

CONCLUSIONS

Our panel study showed that exposure to residential surrounding green space was associated with better cognitive performances at 9-12 years of age, taking into account traffic-related air pollution exposure. These findings support the necessity to build attractive green spaces in the residential environment to promote healthy cognitive development in children.

Association of indoor dust microbiota with cognitive function and behavior in preschool-aged children

BACKGROUND

Childhood cognitive development depends on neuroimmune interactions. Immunomodulation by early-life microbial exposure may influence neuropsychological function. In this study, we investigate the association between residential indoor microbiota and cognition and behavior among preschoolers.

RESULTS

Indoor-settled dust bacterial and fungal characteristics were assessed using 16S and ITS amplicon sequencing (microbial diversity) and qPCR measurements (microbial loads). Child behavior was assessed using four scales: peer relationship, emotional, conduct, and hyperactivity was assessed by the Strengths and Difficulties Questionnaire (SDQ). Cognitive function was assessed using four tasks of the Cambridge Neuropsychological Test Automated Battery (CANTAB) software. The first two tasks were designed to assess attention and psychomotor speed (Motor Screening (MOT) and Big/Little Circle (BLC)) and the last two to evaluate the child's visual recognition/working memory (Spatial Span (SSP) and Delayed Matching to Sample (DMS)). Among the 172 included children (age 4-6 years), we observed a 51% (95%CI;75%;9%) lower odds of children scoring not normal for hyperactivity and a decrease of 3.20% (95%CI, -6.01%; -0.30%) in BLC response time, for every IQR increase in fungal Shannon diversity. Contrarily, microbial loads were directly associated with SDQ scales and response time. For example, a 2-fold increase in Gram-positive bacterial load was associated with 70% (95%CI 18%; 156%) higher odds of scoring not normal for hyperactivity and an increase of 5.17% (95%CI 0.87%; 9.65%) in DMS response time.

CONCLUSIONS

Our findings show that early-life exposure to diverse indoor fungal communities is associated with better behavioral and cognitive outcomes, whereas higher indoor microbial load was associated with worse outcomes. Video Abstract.

Assessing the impact of urban greenspace on physical health: An empirical study from Southwest China

Introduction

As the world becomes increasingly urbanized and human-nature contact declines, urban greenspace's impact on human health has garnered growing interest across academic disciplines. Various definitions and multiple indicators of greenspace have been utilized, with most studies finding an overall positive association between greenspace and health. Nevertheless, studies directly comparing how different greenspace indicators impact different disease types have been limited. Moreover, to verify the robustness of conclusions drawn, studies should compare multiple measures of greenspace across various spatial scales. Thus, a more comprehensive analysis is necessary to help inform future study design, especially in determining which greenspace indicators would be most useful in data-limited areas.

Methods

Chengdu, the capital city of Sichuan Province, is West China's largest and most urban city, being typical of other large cities in lower to middle-income countries (LMICs). With twenty county-level jurisdictions spanning various degrees of urbanization, Chengdu's landscape heterogeneity and large population make it ideal for studying greenspace's impact on public health. This study took Chengdu as a case study to assess the association and potential impact of three traditional measures of greenspace (Normalized Difference Vegetation Index, Enhanced Vegetation Index, and Fractional Vegetation Cover) and urban ratio (% of population being urban) on hospitalization rates and medical expenses paid for three major disease categories (circulatory system diseases, neoplasms, and respiratory system diseases).

Results and discussion

We found greenspace did have a significant impact on public health, but this relationship differed by disease type. Greenspace exhibited significant positive association with respiratory diseases, but insignificant negative associations with the other disease categories. Urban ratio showed significant negative association with greenspace abundance. The higher the urban ratio (e.g., less greenspace), the more money was paid on medical expenses. This relationship was found not only in terms of urban ratio being positively correlated with medical expenses, but also in that all three greenspace indicators were negatively correlated with medical expenses. Consequently, in future health outcome studies, urban ratio could be an acceptable negative indicator of greenness in LMICs where urban ratio is likely to imply less greenness.

Greenspace and health outcomes in children and adolescents: A systematic review

An increasing body of evidence has linked greenspace and various health outcomes in children and adolescents, but the conclusions were inconsistent. For this review, we comprehensively summarized the measurement methods of greenspace, resultant health outcomes, and potential mechanisms from epidemiological studies in children and adolescents (aged ≤19 years). We searched for studies published and indexed in MEDLINE and EMBASE (via Ovid) up to April 11, 2022. There were a total of 9,291 studies identified with 140 articles from 28 countries finally assessed and included in this systematic review. Over 70% of the studies were conducted in highly urbanised countries/regions, but very limited research has been done in low-and middle-income countries and none in Africa. Measures of greenspace varied. Various health outcomes were reported, including protective effects of greenspace exposure on aspects of obesity/overweight, myopia, lung health, circulatory health, cognitive function, and general health in children and adolescents. The associations between greenspace exposure and other health outcomes were inconsistent, especially for respiratory health studies. We pooled odds ratios (OR) using random-effects meta-analysis for health outcomes of asthma (OR = 0.94, 95%CI: 0.84 to 1.06), allergic rhinitis (OR = 0.95; 95% CI: 0.73 to 1.25), and obesity/overweight (OR = 0.91, 95%CI: 0.84 to 0.98) with per 0.1 unit increase in normalized difference in vegetation index (NDVI). These associations have important implications for the assessment and management of urban environment and health in children and adolescents.

Neighborhood influences on the development of self-regulation among children of color living in historically disinvested neighborhoods: Moderators and mediating mechanisms

We present a conceptual model of the ways in which built and social environments shape the development of self-regulation in early childhood. Importantly, in centering children of color growing up in historically disinvested neighborhoods, we first describe how systemic structures of racism and social stratification have shaped neighborhood built and social environment features. We then present evidence linking these neighborhood features to children's development of self-regulation. Furthermore, we take a multilevel approach to examining three potential pathways linking neighborhood contexts to self-regulation: school environment and resources, home environment and resources, and child health behaviors. Finally, we consider how racial-ethnic-cultural strengths and multilevel interventions have the potential to buffer children's development of self-regulation in disinvested neighborhood contexts. Advancing multilevel approaches to understand the development of self-regulation among children of color living in historically disinvested neighborhoods is an important step in efforts to promote equity in health and education.

Higher buccal mtDNA content is associated with residential surrounding green in a panel study of primary school children

BACKGROUND

Mitochondria are known to respond to environmental stressors but whether green space is associated with mitochondrial abundance is unexplored. Furthermore, as exposures may affect health from early life onwards, we here evaluate if residential green space is associated with mitochondria DNA content (mtDNAc) in children.

METHODS

In primary schoolchildren (COGNAC study), between 2012 and 2014, buccal mtDNAc was repeatedly (three times) assessed using qPCR. Surrounding low (<3m), high (≥3m) and total (sum of low and high) green space within different radii (100m-1000m) from the residence and distance to the nearest large green space (>0.5ha) were estimated using a remote sensing derived map. Given the repeated measures design, we applied a mixed-effects model with school and subject as random effect while adjusting for a priori chosen fixed covariates.

RESULTS

mtDNAc was assessed in 246 children with a total of 436 measurements (mean age 10.3 years). Within a 1000m radius around the residential address, an IQR increment in low (11.0%), high (9.5%), and total (13.9%) green space was associated with a respectively 15.2% (95% CI: 7.2%-23.7%), 10.8% (95% CI: 4.5%-17.5%), and 13.4% (95% CI: 7.4%-19.7%) higher mtDNAc. Conversely, an IQR increment (11.6%) in agricultural area in the same radius was associated with a -3.4% (95% CI: 6.7% to -0.1%) lower mtDNAc. Finally, a doubling in distance to large green space was associated with a -5.2% (95% CI: 7.9 to -2.4%) lower mtDNAc.

CONCLUSION

To our knowledge, this is the first study evaluating associations between residential surrounding green space and mtDNAc in children. Our results showed that green space was associated with a higher mtDNAc in children, which indicates the importance of the early life environment. To what extent these findings contribute to later life health effects should be further examined.

Long-Term Exposure to Greenspace and Cognitive Function during the Lifespan: A Systematic Review

Recent advances in environmental psychology highlighted the beneficial role of greenspace exposure on cognition. We conducted a systematic review of the available studies on the association of long-term exposure to greenspace and cognitive functions across the lifespan. PRISMA guidelines and the PECOs method were applied to screen for eligible studies. Twenty-five studies from Scopus, PubMed, and PsycINFO met the inclusion criteria. Six studies were longitudinal and nineteen cross-sectional. Fifteen studies focused on schoolchildren, six studies on adults, and four on the elderly. Twenty studies used the NDVI to assess greenspace exposure and the remaining used other indexes. Eight studies employed academic achievement as the outcome, eight studies global cognition, six studies attention/executive functions, and three studies memory. The evidence was inconsistent but suggestive for a beneficial role of greenspace exposure on cognitive functions. Further studies are required, especially among adults and older people, by adopting longitudinal designs.

Growing up green: a systematic review of the influence of greenspace on youth development and health outcomes

Youth growing up in places with more greenspaces have better developmental outcomes. The literature on greenspace and youth development is largely cross-sectional, thus limited in terms of measuring development and establishing causal inference. We conducted a systematic review of prospective, longitudinal studies measuring the association between greenspace exposure and youth development outcomes measured between ages two and eighteen. We searched Cochrane, PubMed, CINAHL, Scopus, and Environment Complete, and included prospective cohort, quasi-experimental, and experimental studies on greenspace and youth development. Study quality was assessed using a 10-item checklist adapted from a previously published review on greenspace and health. Twenty-eight studies met criteria for review and were grouped into five thematic categories based on reported outcomes: cognitive and brain development, mental health and wellbeing, attention and behavior, allergy and respiratory, and obesity and weight. Seventy-nine percent of studies suggest an association between greenspace and improved youth development. Most studies were concentrated in wealthy, Western European countries, limiting generalizability of findings. Key opportunities for future research include: (1) improved uniformity of standards in measuring greenspace, (2) improved measures to account for large latency periods between greenspace exposure and developmental outcomes, and (3) more diverse study settings and populations.

Residential greenspace and early childhood development and academic performance: A longitudinal analysis of Australian children aged 4-12 years

INTRODUCTION

Exposure to greenspaces has beneficial effects on children's mental health and development. This study explores the association between residential exposure to greenspace and early childhood development and academic outcomes.

METHODS

Children were from Mothers and their Children's Health (MatCH) study, a sub-study of the Australian Longitudinal Study on Women's Health. We obtained data on early childhood development from the Australian Early Development Census (AEDC), a population-wide census data (n = 936 children, mean age: 5.3, SD: 0.5 years). Academic performance relative to the national minimum standard (NMS) (i.e., in reading, writing, grammar and punctuation, spelling, and numeracy) of children with Year 3 and 5 data were from the 'National Assessment Program - Literacy and Numeracy' (NAPLAN) (n = 1679 children). Annual exposure to green and non-green vegetation was measured using the Normalized Difference Vegetation Index (NDVI) and fractional cover of non-photosynthetic vegetation (fNPV), respectively, within 100 m and 500 m buffer zone of maternal residential address. We calculated greenspace exposure at the year of test and average exposure throughout childhood. Greenspace exposures were standardised and odds ratio (ORs) with 95% confidence intervals (95% CI) were estimated using generalised estimating equation models, adjusting for potential confounders.

RESULTS

Exposure to fNPV within 500 m buffer of homes at the year of test and during child's lifetime was associated with academic scores below/at NMS at Year 3 (baseline) and Year 5 (follow-up) for the domains of reading, writing, and grammar and punctuation. Surrounding residential greenness was not significantly associated with NAPLAN scores. No association was found between residential greenspace and developmental vulnerability on one or more AEDC domains across both exposure windows.

CONCLUSION

Our study revealed that long-term and short-term exposure to non-green vegetation around homes is linked to poor academic performance in children. Further research on fNPV is required to verify these findings, with additional longitudinal studies.

Effects of residential greenness on attention in a longitudinal study at 8 and 11-13 years

In an urbanizing world, with 55% of the population living in cities, it is essential to design friendly and healthy ones. An emerging body of evidence has associated greenspace exposure with improved cognitive development, including attentional function; however, the longitudinal studies looking at the association with attentional function are still scarce. Therefore, the objective of this study was to analyze the association of the exposure to greenspace and attention in school children. This study was based on 751 participants at 8 years and 598 at 11-13 years of two sub-cohorts of the INMA cohort study in Gipuzkoa and Asturias, Spain. Greenspace exposure at home was characterized using four indicators: (i) average of Normalized Difference Vegetation Index (NDVI) and (ii) Vegetation Continuous Field (VCF) in buffers of 100 m, 300 m, and 500 m around the residential address, (ii) availability of a green space within 300 m from the residential address, and (iv) residential distance to green spaces. Participants' attention was characterized twice at ages of 8 and 11 years, using the computerized Attentional Network Test (ANT). General linear models were used for the cross-sectional analyses and linear mixed effects model for the longitudinal analyses. Our cross-sectional analyses showed a statistical significant protective association between average NDVI at 300 m and inattentiveness (-7.20, CI 95%: 13.74; -0.67). In our longitudinal analyses, although we generally observed beneficial associations between greenspace exposure and attention, none attained statistical significance. No statistically significant indirect effect were seen for NO₂. Our findings add to the emerging body of evidence on the role of green spaces in neurodevelopment, which can provide the evidence base for implementing intervention aimed at promoting neurodevelopment in urban children.

Residential green space in association with the methylation status in a CpG site within the promoter region of the placental serotonin receptor HTR2A

Green space could influence adult cognition and childhood neurodevelopment , and is hypothesized to be partly driven by epigenetic modifications. However, it remains unknown whether some of these associations are already evident during foetal development. Similar biological signals shape the developmental processes in the foetal brain and placenta.Therefore, we hypothesize that green space can modify epigenetic processes of cognition-related pathways in placental tissue, such as DNA-methylation of the serotonin receptor HTR2A. HTR2A-methylation was determined within 327 placentas from the ENVIRONAGE (ENVIRonmental influence ON early AGEing) birth cohort using bisulphite-PCR-pyrosequencing. Total green space exposure was calculated using high-resolution land cover data derived from the Green Map of Flanders in seven buffers (50 m-3 km) and stratified into low (<3 m) and high (≥3 m) vegetation. Residential nature was calculated using the Land use Map of Flanders. We performed multivariate regression models adjusted for several a priori chosen covariables. For an IQR increment in total green space within a 1,000 m, 2,000 m and 3,000 m buffer the methylation of HTR2A increased with 1.47% (95%CI:0.17;2.78), 1.52% (95%CI:0.21;2.83) and 1.42% (95%CI:0.15;2.69), respectively. Additionally,, we found 3.00% (95%CI:1.09;4.91) and 1.98% (95%CI:0.28;3.68) higher HTR2A-methylation when comparing residences with and without the presence of nature in a 50 m and 100 m buffer, respectively. The methylation status of HTR2A in placental tissue is positively associated with maternal green space exposure. Future research is needed to understand better how these epigenetic changes are related to functional modifications in the placenta and the consequent implications for foetal development.

The influence of early-life residential exposure to different vegetation types and paved surfaces on early childhood development: A population-based birth cohort study

BACKGROUND

Growing evidence suggests that exposure to green space is associated with improved childhood health and development, but the influence of different green space types remains relatively unexplored. In the present study, we investigated the association between early-life residential exposure to vegetation and early childhood development and evaluated whether associations differed according to land cover types, including paved land.

METHODS

Early childhood development was assessed via kindergarten teacher-ratings on the Early Development Instrument (EDI) in a large population-based birth cohort (n = 27,539) in Metro Vancouver, Canada. The residential surrounding environment was characterized using a high spatial resolution land cover map that was linked to children by six-digit residential postal codes. Early-life residential exposure (from birth to time of EDI assessment, mean age = 5.6 years) was calculated as the mean of annual percentage values of different land cover classes (i.e., total vegetation, tree cover, grass cover, paved surfaces) within a 250 m buffer zone of postal code centroids. Multilevel models were used to analyze associations between respective land cover classes and early childhood development.

RESULTS

In adjusted models, one interquartile range increase in total vegetation percentage was associated with a 0.33 increase in total EDI score (95% CI: 0.21, 0.45). Similar positive associations were observed for tree cover (β-coefficient: 0.26, 95% CI: 0.15, 0.37) and grass cover (β-coefficient: 0.12, 95% CI: 0.02, 0.22), while negative associations were observed for paved surfaces (β-coefficient: -0.35, 95% CI: -0.47, -0.23).

CONCLUSIONS

Our findings indicate that increased early-life residential exposure to vegetation is positively associated with early childhood developmental outcomes, and that associations may be stronger for residential exposure to tree cover relative to grass cover. Our results further indicate that childhood development may be negatively associated with residential exposure to paved surfaces. These findings can inform urban planning to support early childhood developmental health.

Park access and mental health among parents and children during the COVID-19 pandemic

BACKGROUND

Time spent outdoors and in nature has been associated with numerous benefits to health and well-being. We examined relationships between park access and mental health for children and parents during the COVID-19 pandemic. We also explored associations between park access and co-participation of parent and child in time outdoors, and child and parent physical activity.

METHODS

We used data from 1,000 respondents to a nationally representative U.S. survey of parent-child dyads during October-November 2020. Park access was defined as an affirmative response to: "do you have a park that you can safely walk to within 10 min of your home?" Child mental health was operationalized as the Strengths and Difficulties Questionnaire (SDQ) total difficulties score. The Patient Health Questionnaire-4 (PHQ-4) total score assessed parent mental health and the International Physical Activity Questionnaire (IPAQ) assessed parent physical activity. Child physical activity and co-participation in outdoor activity were reported as number of days in the prior week. Linear regression was used to examine relationships between park access and health outcomes in models adjusted for child and parent characteristics and COVID-19 impact.

RESULTS

Our sample included 500 parents of children ages 6-10 years, and 500 parent-child dyads of children ages 11-17 years. Park access was associated with a lower SDQ total score among children (β: -1.26, 95% CI: -2.25, -0.27) and a lower PHQ-4 total score among parents (β: -0.89, 95% CI: -1.39, -0.40). In models stratified by child age, these associations were observed for SDQ scores among adolescents ages 11-17 and for PHQ-4 scores among parents of children ages 6-10 years. Park access was also associated with 0.50 more days/week of co-participation in outdoor time (95% CI: 0.16, 0.84), and higher levels of parent physical activity (β: 1009 MET-min/week, 95% CI: 301, 1717), but not child physical activity (β: 0.31 days/week, 95% CI: -0.03, 0.66).

CONCLUSIONS

Park access was associated with better mental health among children and parents, and more parent physical activity and parent-child co-participation in outdooractivity during the COVID-19 pandemic. Access to nearby parks may be an important resource to promote health and well-being, for both individuals and families.

Early life exposure to residential green space impacts cognitive functioning in children aged 4 to 6 years

INTRODUCTION

During early childhood, neuronal networks are highly susceptible to environmental factors. Previous research suggests that green space exposure is beneficial for cognitive functioning. Here, we investigate the associations between residential green space exposure and behavioral problems and cognitive development in children aged four to six years.

METHOD

We included children participating in the ENVIRONAGE birth cohort. Residential green spaces were calculated based on high-resolution land cover data within several buffers (50-1,000 m) around the residence. The children's behavior was assessed with the Strengths and Difficulties Questionnaire (SDQ) among 411 children. In addition, to evaluate cognitive function, 456 children completed four tasks of the Cambridge Neuropsychological Test Automated Battery (CANTAB). We used multivariate logistic and linear regression models while accounting for potential confounders and covariables.

RESULTS

An interquartile (IQR) increase of residential green space within 50 m was associated with a 38% (95% CI: 56;14) lower odds of a child having hyperactivity problems. Additionally, we found a beneficial influence of residential green space in close proximity (50-100 m) on the attention and psychomotor speed, represented by the Motor Screening Task. For example, we found a decrease of 0.45 (95% CI: -0.82;-0.09) pixel units from target center with an IQR increase of residential green space in a 50 m buffer. In addition, we observed an improved visual recognition/working memory, represented by the Delayed Matching to Sample Task within all included buffers (50-1000 m). For example, we observed a decrease of 4.91% (95 %CI: -7.46;-2.36) probability of an error occurring if the previous trial was correct and a 2.02% (95 %CI: 0.08; 3.97) increase of correct trials with an IQR increase of green space within a 100 m buffer.

CONCLUSION

This study provides additional indications for a beneficial influence of green space exposure on the development of behavioral problems and cognitive function as young as four years of age.

Neighborhood environmental exposures and incidence of attention deficit/hyperactivity disorder: A population-based cohort study

BACKGROUND

Emerging studies have associated low greenspace and high air pollution exposure with risk of child attention deficit/hyperactivity disorder (ADHD). Population-based studies are limited, however, and joint effects are rarely evaluated. We investigated associations of ADHD incidence with greenspace, air pollution, and noise in a population-based birth cohort.

METHODS

We assembled a cohort from administrative data of births from 2000 to 2001 (N ∼ 37,000) in Metro Vancouver, Canada. ADHD was identified by hospital records, physician visits, and prescriptions. Cox proportional hazards models were applied to assess associations between environmental exposures and ADHD incidence adjusting for available covariates. Greenspace was estimated using vegetation percentage derived from linear spectral unmixing of Landsat imagery. Fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) were estimated using land use regression models; noise was estimated using a deterministic model. Exposure period was from birth until the age of three. Joint effects of greenspace and PM_2.5 were analysed in two-exposure models and by categorizing values into quintiles.

RESULTS

During seven-year follow-up, 1217 ADHD cases were diagnosed. Greenspace was associated with lower incidence of ADHD (hazard ratio, HR: 0.90 [0.81-0.99] per interquartile range increment), while PM_2.5 was associated with increased incidence (HR: 1.11 [1.06-1.17] per interquartile range increment). NO₂ (HR: 1.01 [0.96, 1.07]) and noise (HR: 1.00 [0.95, 1.05]) were not associated with ADHD. There was a 50% decrease in the HR for ADHD in locations with the lowest PM_2.5 and highest greenspace exposure, compared to a 62% increase in HR in locations with the highest PM_2.5 and lowest greenspace exposure. Effects of PM_2.5 were attenuated by greenspace in two-exposure models.

CONCLUSIONS

We found evidence suggesting environmental inequalities where children living in greener neighborhoods with low air pollution had substantially lower risk of ADHD compared to those with higher air pollution and lower greenspace exposure.

Effects of air pollution and green spaces on impaired lung function in children: a case-control study

The occurrences of impaired lung function during childhood could substantially influence the health states of the respiratory system in adults. So, the effects of air pollution and green spaces on impaired lung function in children were investigated in this study. The lung function of each student was tested every year from 2015 to 2017 and the method of case-control study was applied. 2087 students aged from 9 to 11 years old of primary schools in Tianjin were ultimately included in this study. The method of propensity score matching (PSM) was performed to minimize the confounding bias and the conditional logistic regression model was carried out to evaluate the effects of indoor and outdoor environmental risk factors on the occurrences of impaired lung function in children. For every interquartile range (IQR) increase in the mixture of six air pollutants at the lag1, lag2, and lag3 periods, the risks of getting impaired lung function were increased by 53.4%, 34.7%, and 16.9%, respectively. The protective effect of greenness at lag2 period (odds ratios (OR)) = 0.022 (95% confidence interval (CI): 0.008-0.035)) was stronger than that at lag1and lag3 periods, respectively. Separate and combined effects of most air pollutants at different lag periods exerted hazardous effects on the lung function of students. Exposure to greenness had protective effects on the lung health of children.

Higher surrounding green space is associated with better attention in Flemish adolescents

INTRODUCTION

Previous studies suggested that green space is beneficial for the cognitive development in children. However, evidence in adolescents is limited. Therefore, we aim to investigate green space exposure in association with attention and behaviour in adolescents.

METHODS

This study includes 596 Flemish adolescents between 13 and 17 years old. Attention was assessed with Stroop Test (selective attention) and Continuous Performance Test (sustained and selective attention). Behaviour was determined based on the Strengths and Difficulties Questionnaire. Green space was estimated in several radius distances around their current residence and school based on high-resolution land cover data. Multilevel regression analyses were used adjusting for participant's age, sex, education level of the mother, and area deprivation index.

RESULTS

Surrounding green space in a 2000 m radius is associated with a faster reaction time in adolescents. An IQR (13%) increment in total green space within 2000 m of the residence and school combined, is associated with a 32.7 ms (95% CI: -58.9 to -6.5; p = 0.02) and a 7.28 ms (95% CI: -11.7 to -2.8; p = 0.001) shorter mean reaction time between the presentation of a stimulus and the response based on the Stroop Test and the Continuous Performance Test. Subdividing green space based on vegetation height, shows that green space higher than 3 m is associated with a faster reaction time of the Continuous Performance Test (-6.50 ms; 95% CI: -10.9 to -2.2; p = 0.004), while low green is not. We did not find an association between green space and behavioural development in adolescents.

CONCLUSIONS

Our study shows that green space, especially trees, surrounding the residence and school combined is associated with better sustained and selected attention in adolescents. These findings indicate that the availability of green is important for adolescents that are growing up in a rapidly urbanizing world.

Early-Life Exposure to Green Space and Mid-Childhood Cognition in the Project Viva Cohort, Massachusetts

The association between early-life greenness and child cognition is not well understood. Using prospective data from Project Viva (n = 857) from 1999-2010, we examined associations of early-life greenness exposure with mid-childhood cognition. We estimated residential greenness at birth, early childhood (median age 3.1 years), and mid-childhood (7.8 years) using 30-m resolution Landsat satellite imagery (normalized difference vegetation index). In early childhood and mid-childhood, we administered standardized assessments of verbal and nonverbal intelligence, visual-motor abilities, and visual memory. We used natural splines to examine associations of early life-course greenness with mid-childhood cognition, adjusting for age, sex, race, income, neighborhood socioeconomic status, maternal intelligence, and parental education. At lower levels of greenness (greenness <0.6), greenness exposure at early childhood was associated with a 0.48% increase in nonverbal intelligence and 2.64% increase in visual memory in mid-childhood. The association between early-childhood greenness and mid-childhood visual memory was observed after further adjusting for early childhood cognition and across different methodologies, while the association with nonverbal intelligence was not. No other associations between early life-course greenness and mid-childhood cognition were found. Early childhood greenness was nonlinearly associated with higher mid-childhood visual memory. Our findings highlight the importance of nonlinear associations between greenness and cognition.

Nature and Children's Health: A Systematic Review

CONTEXT

Daily outdoor play is encouraged by the American Academy of Pediatrics. Existing evidence is unclear on the independent effect of nature exposures on child health.

OBJECTIVE

We systematically evaluated evidence regarding the relationship between nature contact and children's health.

DATA SOURCES

The database search was conducted by using PubMed, Cumulative Index to Nursing and Allied Health Literature, PsychInfo, ERIC, Scopus, and Web of Science in February 2021.

STUDY SELECTION

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. In all searches, the first element included nature terms; the second included child health outcome terms.

DATA EXTRACTION

Of the 10 940 studies identified, 296 were included. Study quality and risk of bias were assessed.

RESULTS

The strongest evidence for type of nature exposure was residential green space studies (n = 147, 50%). The strongest evidence for the beneficial health effects of nature was for physical activity (n = 108, 32%) and cognitive, behavioral, or mental health (n = 85, 25%). Physical activity was objectively measured in 55% of studies, and 41% of the cognitive, behavioral, or mental health studies were experimental in design.

LIMITATIONS

Types of nature exposures and health outcomes and behaviors were heterogenous. Risk of selection bias was moderate to high for all studies. Most studies were cross-sectional (n = 204, 69%), limiting our ability to assess causality.

CONCLUSIONS

Current literature supports a positive relationship between nature contact and children's health, especially for physical activity and mental health, both public health priorities. The evidence supports pediatricians in advocating for equitable nature contact for children in places where they live, play, and learn.

Early life multiple exposures and child cognitive function: A multi-centric birth cohort study in six European countries

Epidemiological studies mostly focus on single environmental exposures. This study aims to systematically assess associations between a wide range of prenatal and childhood environmental exposures and cognition. The study sample included data of 1298 mother-child pairs, children were 6-11 years-old, from six European birth cohorts. We measured 87 exposures during pregnancy and 122 cross-sectionally during childhood, including air pollution, built environment, meteorology, natural spaces, traffic, noise, chemicals and life styles. The measured cognitive domains were fluid intelligence (Raven's Coloured Progressive Matrices test, CPM), attention (Attention Network Test, ANT) and working memory (N-Back task). We used two statistical approaches to assess associations between exposure and child cognition: the exposome-wide association study (ExWAS) considering each exposure independently, and the deletion-substitution-addition algorithm (DSA) considering all exposures simultaneously to build a final multiexposure model. Based on this multiexposure model that included the exposure variables selected by ExWAS and DSA models, child organic food intake was associated with higher fluid intelligence (CPM) scores (beta = 1.18; 95% CI = 0.50, 1.87) and higher working memory (N-Back) scores (0.23; 0.05, 0.41), and child fast food intake (-1.25; -2.10, -0.40), house crowding (-0.39; -0.62, -0.16), and child environmental tobacco smoke (ETS) (-0.89; -1.42, -0.35), were all associated with lower CPM scores. Indoor PM2.5 exposure was associated with lower N-Back scores (-0.09; -0.16, -0.02). Additional associations in the unexpected direction were found: Higher prenatal mercury levels, maternal alcohol consumption and child higher perfluorooctane sulfonic acid (PFOS) levels were associated with better cognitive performance; and higher green exposure during pregnancy with lower cognitive performance. This first comprehensive and systematic study of many prenatal and childhood environmental risk factors suggests that unfavourable child nutrition, family crowdedness and child indoor air pollution and ETS exposures adversely and cross-sectionally associate with cognitive function. Unexpected associations were also observed and maybe due to confounding and reverse causality.

Associations between neighborhood greenspace and brain imaging measures in non-demented older adults: the Cardiovascular Health Study

PURPOSE

Greater neighborhood greenspace has been associated with brain health, including better cognition and lower odds of Alzheimer's disease in older adults. We investigated associations between neighborhood greenspace and brain-based magnetic resonance imaging (MRI) measures and potential effect modification by sex or apolipoprotein E genotype (APOE), a risk factor for Alzheimer's disease.

METHODS

We obtained a sample of non-demented participants 65 years or older (n = 1125) from the longitudinal, population-based Cardiovascular Health Study (CHS). Greenspace data were derived from the National Land Cover Dataset. Adjusted multivariable linear regression estimated associations between neighborhood greenspace five years prior to the MRI and left and right hippocampal volume and 10-point grades of ventricular size and burden of white matter hyperintensity. Interaction terms tested effect modification by APOE genotype and sex. CHS data (1989-1999) were obtained/analyzed in 2020.

RESULTS

Participants were on average 79 years old [standard deviation (SD) = 4], 58% were female, and 11% were non-white race. Mean neighborhood greenspace was 38% (SD = 28%). Greater proportion of greenspace in the neighborhood five years before MRI was borderline associated with lower ventricle grade (estimate: - 0.30; 95% confidence interval: - 0.61, 0.00). We observed no associations between greenspace and the other MRI outcome measures and no evidence of effect modification by APOE genotype and sex.

CONCLUSION

This study suggests a possible association between greater greenspace and less ventricular enlargement, a measure reflecting global brain atrophy. If confirmed in other longitudinal cohort studies, interventions and policies to improve community greenspaces may help to maintain brain health in older age.

Is Brief Exposure to Green Space in School the Best Option to Improve Attention in Children?

The positive effects of Green Spaces on health are thought to be achieved through the mechanisms of mitigation, instoration and restoration. One of the benefits of Green Spaces may be the restoration of attention and so the objective of this research is testing empirically whether exposure to a green environment improves attention in school children. For so doing, we first used a split-unit statistical design in each of four schools, then combined the primary results via meta-analysis. The Attention Network Test (ANT) was used to measure attention before and after exposure and a total of 167 seven-year-old students participated in the experiments. Overall, our experimental results do not support the hypothesis that students’ exposure to activities in green vs. grey spaces affected their performance in ANT. This was so despite the fact that neither age nor gender biases have been detected and despite that our experiments have been proved to be sufficiently statistically powerful. It would be advisable to consider air pollution and noise. We also recommend that participants attend the experiment with mental exhaustion to maximize the ability to detect significant changes.

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.

The association between natural environments and childhood mental health and development: A systematic review and assessment of different exposure measurements

BACKGROUND

Several studies have assessed the relationship between exposure to natural environments (NEs) and childhood mental health and development. In most cases, a positive association has been found, but results are inconsistent, and the strength of association is unclear. This inconsistency may reflect the heterogeneity in measurements used to assess NE.

OBJECTIVES

This systematic review aims to identify the most common NE metrics used in childhood mental health and development research. Our second aim is to identify the metrics that are most consistently associated with health and assess the relative strength of association depending on type of NE exposure measurement, in terms of metric used (i.e., measurement technique, such as remote sensing), but also rate (i.e., spatial and temporal exposure).

METHODS

We used the PRISMA protocol to identify eligible studies, following a set of pre-defined inclusion criteria based on the PECOS strategy. A number of keywords were used for retrieving relevant articles from Medline, Embase, PsychINFO, and Web of Science databases between January 2000-November 2020. From these, we extracted data on type of NE measurement and relative association to a number of indicators of childhood mental health and development. We conducted a systematic assessment of quality and risk of bias in the included articles to evaluate the level of evidence. Case studies and qualitative studies were excluded.

RESULTS

After screening of title (283 studies included), abstract, and full article, 45 studies were included in our review. A majority of which were conducted in North America and Europe (n = 36; 80%). The majority of studies used land use or land covers (LULC, n = 24; 35%) to determine exposures to NEs. Other metrics included the normalized difference vegetation index (NDVI), expert measures (e.g., surveys of data collection done by experts), surveys (e.g., self-reported assessments), and use of NE (e.g., measures of a participant's use of NE such as through GPS tracts or parent reports). Rate was most commonly determined by buffer zones around residential addresses or postal codes. The most consistent association to health outcomes was found for buffers of 100 m, 250 m, 500 m, and within polygons boundaries (e.g., census tracts). Six health categories, academic achievement, prevalence of doctor diagnosed disorders, emotional and behavioral functioning, well-being, social functioning, and cognitive skills, were created post hoc. We found sufficient evidence between NDVI (Landsat) and emotional and behavioral well-being. Additionally, we found limited evidence between LULC datasets and academic achievement; use of NE, parent/guardian reported greenness, and expert measures of greenness and emotional and behavioral functioning; and use of NE and social functioning.

DISCUSSION

This review demonstrates that several NE measurements must be evaluated further before sufficient evidence for a potential association between distinct NE exposure metrics and childhood mental health and development can be established. Further, we suggest increased coordination between research efforts, for example, by replication of studies and comparing different NE measurements systematically, so that effect sizes can be confirmed for various health outcomes. Finally, we recommend implementing research designs that assess underlying pathways of nature-health relations and utilize measurement techniques that adequately assess exposure, access, use, and perception of NEs in order to contribute to a better understanding of health impacts of surrounding natural environments.

Outdoor green space exposure and brain health measures related to Alzheimer's disease: a rapid review

OBJECTIVES

Summarise studies of outdoor green space exposure and brain health measures related to Alzheimer's disease and related disorders (ADRD), and determine scientific gaps for future research.

DESIGN

Rapid review of primary research studies.

METHODS AND OUTCOMES

PubMed, Embase and Web of Science Core Collection were searched for articles meeting the criteria published on/before 13 February 2020. The review excluded papers not in English, focused on transient states (eg, mental fatigue) or not using individual-level measures of brain health (eg, average school test scores). Brain health measures of interest included cognitive function, clinical diagnosis of cognitive impairment/dementia/ADRD and brain biomarkers such as those from MRI, measures typically associated with ADRD risk and disease progression.

RESULTS

Twenty-two papers were published from 2012 to 2020, 36% on <18 years old, 32% on 18-64 years old and 59% on ≥65 years old. Sixty-four per cent defined green space based on the Normalised Difference Vegetation Index ('greenness'/healthy vegetation) and 68% focused on cognitive measures of brain health (eg, memory). Seventeen studies (77%) found green space-brain health associations (14 positive, 4 inverse). Greater greenness/green space was positively associated various cognitive domains in 10 studies and with MRI outcomes (regional brain volumes, cortical thickness, amygdala integrity) in three studies. Greater neighbourhood greenness was associated with lower odds/risk of cognitive impairment/ADRD in some studies but increased odds/risk in others (n=4 studies).

CONCLUSIONS

Published studies suggest positive green space-brain health associations across the life course, but the methods and cohorts were limited and heterogeneous. Future research using racially/ethnically and geographically diverse cohorts, life course methods and more specific green space and brain health measures (eg, time spent in green spaces, ADRD biomarkers) will strengthen evidence for causal associations.

Green spaces and cognitive development at age 7 years in a rome birth cohort: The mediating role of nitrogen dioxide

Introduction There is evidence of improvement on mental health and well-being due to contact with green spaces, through various mechanisms and with potentially differential impacts in different populations. Many of these studies have been conducted among adults, while children have not been sufficiently investigated. This study aimed to evaluate the association between residential exposure to greenness and cognitive development at age 7 and to evaluate nitrogen dioxide (NO₂) as a potential mediator of this association.Methods This longitudinal study was based on a cohort of newborns enrolled at delivery in two large obstetric hospitals in Rome. We assessed cognitive development at 7 years of age through the Wechsler Intelligence Scale for Children-III edition (WISC-III). We estimated residential surrounding greenness, using satellite derived Normalized Difference Vegetation Index (NDVI), within 300m and 500m buffers around each residential address at birth. We applied weighted multiple linear regression analyses to study the association between NDVI and the WISC-III cognitive scores, using the inverse probability weighting methodology to correct for potential selection bias. We performed a mediation analysis to evaluate the mediating role of NO₂ in the association under study.Results We enrolled 719 children at birth and performed our analyses only on 465 children with data on exposure and outcome. The results were not consistent for the average residential surrounding greenness in 300m buffer. For an IQR increase in greenness within 500m buffer around home addresses at birth we found a progress in Arithmetic subtest (β:0.39; 90% CI: 0.11-0.6), a test concerning with attention, concentration and numerical reasoning, apart from an indication of the positive association with Full scale IQ and Verbal IQ. This association was partly mediated by reduction in NO₂, since adding this pollutant in our model explained 35% (90% CI: 7%-62%) of our estimate.Conclusions Our findings showed an association between residential surrounding greenness within 500m and better scores on attention tests at 7 years of age. The observed association between Arithmetic subtest and NDVI was mediated, in part, by a reduction in NO₂. This topic has important public health implications in supporting green urban planning policies and promoting children's well-being.

Virtual Reality Representations of Nature to Improve Well-Being amongst Older Adults: a Rapid Review

Poor well-being amongst older adults poses a serious health concern. Simultaneously, research shows that contact with nature can improve various facets of well-being, including physical, social, and mental well-being. However, nature is not always accessible for older adults due to mobility restrictions and related care needs that come with age. A promising strategy aims at bringing nature inside through pervasive technologies. However, so far, there is little academic understanding of essential nature characteristics, psychological processes involved, and means for implementation in practice. The current study used a three-folded rapid review to assess current understanding and strategies used for improving well-being for older adults through virtual reality representations of nature. Searches were performed across three databases, followed-up by content-based evaluation of abstracts. In total, a set of 25 relevant articles was identified. Only three studies specifically focus on digital nature as an intervention strategy for improving well-being amongst older adults. Although these studies provide useful starting points for the design and (technological) development of such environments, they do not generate understanding of how specific characteristics of virtual nature representations impact social well-being measures in particular, and of the underlying psychological processes involved. We conclude that follow-up research is warranted to close the gap between insights and findings from nature research, gerontology, health research, and human-technology interaction.

The environmental enrichment model revisited: A translatable paradigm to study the stress of our modern lifestyle

Mounting evidence shows that physical activity, social interaction and sensorimotor stimulation provided by environmental enrichment (EE) exert several neurobehavioural effects traditionally interpreted as enhancements relative to standard housing (SH) conditions. However, this evidence rather indicates that SH induces many deficits, which could be ameliorated by exposing animals to an environment vaguely mimicking some features of their wild habitat. Rearing rodents in social isolation (SI) can aggravate such deficits, which can be restored by SH or EE. It is not surprising, therefore, that most preclinical stress models have included severe and unnatural stressors to produce a stress response prominent enough to be distinguishable from SH or SI-frequently used as control groups. Although current stress models induce a stress-related phenotype, they may fail to represent the stress of our urban lifestyle characterized by SI, poor housing and working environments, sedentarism, obesity and limited access to recreational activities and exercise. In the following review, we discuss the stress of living in urban areas and how exposures to and performing activities in green environments are stress relievers. Based on the commonalities between human and animal EE, we discuss how models of housing conditions (e.g., SI-SH-EE) could be adapted to study the stress of our modern lifestyle. The housing conditions model might be easy to implement and replicate leading to more translational results. It may also contribute to accomplishing some ethical commitments by promoting the refinement of procedures to model stress, diminishing animal suffering, enhancing animal welfare and eventually reducing the number of experimental animals needed.

A critical review of the epidemiological evidence of effects of air pollution on dementia, cognitive function and cognitive decline in adult population

Dementia is arguably the most pressing public health challenge of our age. Since dementia does not have a cure, identifying risk factors that can be controlled has become paramount to reduce the personal, societal and economic burden of dementia. The relationship between exposure to air pollution and effects on cognitive function, cognitive decline and dementia has stimulated increasing scientific interest in the past few years. This review of the literature critically examines the available epidemiological evidence of associations between exposure to ambient air pollutants, cognitive performance, acceleration of cognitive decline, risk of developing dementia, neuroimaging and neurological biomarker studies, following Bradford Hill guidelines for causality. The evidence reviewed has been consistent in reporting associations between chronic exposure to air pollution and reduced global cognition, as well as impairment in specific cognitive domains including visuo-spatial abilities. Cognitive decline and dementia incidence have also been consistently associated with exposure to air pollution. The neuro-imaging studies reviewed report associations between exposure to air pollution and white matter volume reduction. Other reported effects include reduction in gray matter, larger ventricular volume, and smaller corpus callosum. Findings relating to ischemic (white matter hyperintensities/silent cerebral infarcts) and hemorrhagic (cerebral microbleeds) markers of cerebral small vessel disease have been heterogeneous, as have observations on hippocampal volume and air pollution. The few studies available on neuro-inflammation tend to report associations with exposure to air pollution. Several effect modifiers have been suggested in the literature, but more replication studies are required. Traditional confounding factors have been controlled or adjusted for in most of the reviewed studies. Additional confounding factors have also been considered, but the inclusion of these has varied among the different studies. Despite all the efforts to adjust for confounding factors, residual confounding cannot be completely ruled out, especially since the factors affecting cognition and dementia are not yet fully understood. The available evidence meets many of the Bradford Hill guidelines for causality. The reported associations between a range of air pollutants and effects on cognitive function in older people, including the acceleration of cognitive decline and the induction of dementia, are likely to be causal in nature. However, the diversity of study designs, air pollutants and endpoints examined precludes the attribution of these adverse effects to a single class of pollutant and makes meta-analysis inappropriate.

Defining pathways to healthy sustainable urban development

Goals and pathways to achieve sustainable urban development have multiple interlinkages with human health and wellbeing. However, these interlinkages have not been examined in depth in recent discussions on urban sustainability and global urban science. This paper fills that gap by elaborating in detail the multiple links between urban sustainability and human health and by mapping research gaps at the interface of health and urban sustainability sciences. As researchers from a broad range of disciplines, we aimed to: 1) define the process of urbanization, highlighting distinctions from related concepts to support improved conceptual rigour in health research; 2) review the evidence linking health with urbanization, urbanicity, and cities and identify cross-cutting issues; and 3) highlight new research approaches needed to study complex urban systems and their links with health. This novel, comprehensive knowledge synthesis addresses issue of interest across multiple disciplines. Our review of concepts of urban development should be of particular value to researchers and practitioners in the health sciences, while our review of the links between urban environments and health should be of particular interest to those outside of public health. We identify specific actions to promote health through sustainable urban development that leaves no one behind, including: integrated planning; evidence-informed policy-making; and monitoring the implementation of policies. We also highlight the critical role of effective governance and equity-driven planning in progress towards sustainable, healthy, and just urban development.

The Association between Residential Green Space in Childhood and Development of Attention Deficit Hyperactivity Disorder: A Population-Based Cohort Study

BACKGROUND

Access to green space has been hypothesized to have a beneficial impact on children's mental well-being and cognitive development. The underlying mechanisms of the mental health benefits of green space are not fully understood, but different pathways have been suggested, such as the psychologically restoring capacities of green space, the ability to facilitate physical activity and social cohesion, and the mitigation of exposure to air pollution.

OBJECTIVES

In this nationwide cohort study, we investigated associations between residential green space in early childhood and a clinical diagnosis of attention deficit hyperactivity disorder (ADHD).

METHODS

The cohort included individuals, who were born in Denmark between 1992 and 2007 (n=814,689) and followed for a diagnosis of ADHD from age 5, during the period 1997-2016. We used the normalized difference vegetation index (NDVI) as a measure of vegetation greenness surrounding each residential address in a quadratic area of 210m×210m in which the residence was located in the center of the quadrate. Individual exposure to green space was calculated as the average of NDVI surrounding each individual's residential address (or addresses if more than one) between birth and the fifth birthday. Multilevel modeling was used to estimate the incidence rate ratios (IRRs) with 95% confidence intervals (CI) for ADHD, according to exposure level and adjusted for calendar time, age, sex, parental socioeconomic status, neighborhood level socioeconomic status, and urbanicity.

RESULTS

Individuals living in areas defined by sparse green vegetation (lowest decile of NDVI) had an increased risk of developing ADHD, compared with individuals living in areas within the highest decile of NDVI (IRR=1.55; 95% CI: 1.46, 1.65). Adjusting for the known confounders attenuated the result, but the association remained (IRR=1.20; 95% CI: 1.13, 1.28).

CONCLUSION

Our findings suggest that lower levels of green space in residential surroundings, during early childhood, may be associated with a higher risk of developing ADHD. https://doi.org/10.1289/EHP6729.

Can United States Healthcare Become Environmentally Sustainable? Towards Green Healthcare Reform

In 2014, the United States health care industry produced an estimated 480 million metric tons of carbon dioxide (CO2); nearly 8% of the country's total emissions. The importance of sustainability in health care - as a business reliant on fossil fuels for transportation, energy, and operational functioning - is slowly being recognized. These efforts to green health care are incomplete, since they only focus on health care structures. The therapeutic relationship is the essence of health care - not the buildings that contain the practice. As such, this article will first postulate reasons for a lack of environmental sustainability in US health care. Second, the article will focus on current green health care initiatives in the United States in which patients and physicians participate. Third, the rationale for participation in green initiatives will be explained. Fourth, the article will propose that, based on the environmental values of patients and physicians, health care insurance plans and health care insurance companies can be targeted for green health care reform, thereby closing the loop of sustainable health care delivery.

Association of greenspace exposure with telomere length in preschool children

Exposure to greenspace has been associated with a wide range of health benefits; however, the available evidence on the association of this exposure with telomere length (TL), an early marker of ageing, is still scarce. We investigated the association of greenspace exposure with TL in a sample of 200 preschool children (aged 5-7 years) residing in Sabzevar, Iran (2017). We comprehensively characterized different aspects of greenspace exposure encompassing residential, kindergarten, and total (including both residential and kindergarten) surrounding greenspace (using satellite-derived Normalized Difference Vegetation Index), residential and kindergarten distance to green spaces, time spent in private gardens and public green spaces, and the number of plant pots at home. Relative leukocyte TL (LTL) in blood samples of the study participants was measured using quantitative polymerase chain reaction (qPCR). We applied mixed effects linear regression models with kindergarten and qPCR plate as random effects, to estimate the association of indicators of greenspace exposure (one at a time) with LTL, controlled for relevant covariates. We observed an inverse association between distance from home and kindergarten to green spaces larger than 5000 m² and LTL. Moreover, higher total surrounding greenspace at 300m and 500m buffers and higher surrounding greenspace at 300m buffer around kindergarten and home were associated with longer LTL. Furthermore, longer time spent (h/week) in the public green spaces was associated with longer LTL. Our findings for residential and kindergarten distance to any green space (regardless of the size), residential surrounding greenspace at 100m and 500m buffers, kindergarten surrounding greenspace at 100m buffer, time spent in private gardens (h/week) and the number of plant pots at home were not conclusive. Our findings were generally suggestive for a positive association between greenspace exposure and LTL in preschool children. More studies are needed to confirm these findings in other settings with different climates and populations.

Prenatal greenspace exposure and cord blood cortisol levels: A cross-sectional study in a middle-income country

Exposure to greenspace has been associated with reduced stress; however, the available evidence on such an association for the fetus is still very scarce. We, for the first time, investigated the association between maternal greenspace exposure and the level of cortisol, a stress hormone, in the cord blood. Our study was based on a cohort of 150 pregnant women in Sabzevar, Iran (2018). We comprehensively assessed greenspace exposure for each participant through (i) residential surrounding greenspace (using two satellite-derived vegetation indices), (ii) residential proximity to green spaces, (iii) maternal visual access to greenspace, (iv) use of public and private green spaces, (v) having a private garden, and (vi) the number of plant pots at home. Linear regression models were developed to assess the association of each indicator of greenspace exposure with cord blood cortisol levels, controlled for the relevant covariates. We observed that a higher residential surrounding greenspace (100 m buffer), having a window with greenspace view, window greenspace coverage of more than 50%, frequently looking at greenspace through window, residential proximity to large green spaces, and more time spent in green spaces were associated with lower cortisol levels in the cord blood. The findings for residential surrounding greenspace at 300 m and 500 m buffers, residential proximity to any green space regardless of its size, having a private garden, and number of plant pots at home were not conclusive. While about one-third of the association between residential surrounding greenspace (100 m buffer) could be mediated through reduction in exposure to air pollution, we did not observe any strong evidence for such a mediatory role for the visual access to greenspace. The findings stratified for parental education and housing type showed mixed patterns. Our findings suggest that more greenspace exposure might reduce cortisol level in the cord blood.

A feasibility study on the association between residential greenness and neurocognitive function in middle-aged Bulgarians

Recent research has indicated that exposure to residential vegetation ("greenness") may be protective against cognitive decline and may support the integrity of the corresponding brain structures. However, not much is known about these effects, especially in less affluent countries and in middle-aged populations. In this study, we investigated the associations between greenness and neurocognitive function. We used a convenience sample of 112 middle-aged Bulgarians and two cognitive tests: the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery (CERAD-NB) and the Montreal Cognitive Assessment (MoCA). In addition, structural brain imaging data were available for 25 participants. Participants' home address was used to link cognition scores to the normalised difference vegetation index (NDVI), a measure of overall neighbourhood vegetation level (radii from 100 to 1,000 m). Results indicated that higher NDVI was consistently associated with higher CERAD-NB and MoCA scores across radial buffers and adjustment scenarios. Lower waist circumference mediated the effect of NDVI on CERAD-NB. NDVI100-m was positively associated with average cortical thickness across both hemispheres, but these correlations turned marginally significant (P<0.1) after correction for false discovery rate due to multiple comparisons. In conclusion, living in a greener neighbourhood might be associated with better cognitive function in middle-aged Bulgarians, with lower central adiposity partially accounting for this effect. Tentative evidence suggests that greenness might also contribute to structural integrity in the brain regions regulating cognitive functions. Future research should build upon our findings and investigate larger and more representative population groups.

Psychological impacts of "screen time" and "green time" for children and adolescents: A systematic scoping review

Technological developments in recent decades have increased young people's engagement with screen-based technologies (screen time), and a reduction in young people's contact with nature (green time) has been observed concurrently. This combination of high screen time and low green time may affect mental health and well-being. The aim of this systematic scoping review was to collate evidence assessing associations between screen time, green time, and psychological outcomes (including mental health, cognitive functioning, and academic achievement) for young children (<5 years), schoolchildren (5-11 years), early adolescents (12-14 years), and older adolescents (15-18 years). Original quantitative studies were identified in four databases (PubMed, PsycInfo, Scopus, Embase), resulting in 186 eligible studies. A third of included studies were undertaken in Europe and almost as many in the United States. The majority of studies were cross-sectional (62%). In general, high levels of screen time appeared to be associated with unfavourable psychological outcomes while green time appeared to be associated with favourable psychological outcomes. The ways screen time and green time were conceptualised and measured were highly heterogeneous, limiting the ability to synthesise the literature. The preponderance of cross-sectional studies with broadly similar findings, despite heterogeneous exposure measures, suggested results were not artefacts. However, additional high-quality longitudinal studies and randomised controlled trials are needed to make a compelling case for causal relationships. Different developmental stages appeared to shape which exposures and outcomes were salient. Young people from low socioeconomic backgrounds may be disproportionately affected by high screen time and low green time. Future research should distinguish between passive and interactive screen activities, and incidental versus purposive exposure to nature. Few studies considered screen time and green time together, and possible reciprocal psychological effects. However, there is preliminary evidence that green time could buffer consequences of high screen time, therefore nature may be an under-utilised public health resource for youth psychological well-being in a high-tech era.

Residential Surrounding Greenspace and Mental Health in Three Spanish Areas

Exposure to greenspace has been related to improved mental health, but the available evidence is limited and findings are heterogeneous across different areas. We aimed to evaluate the associations between residential exposure to greenspace and specific psychopathological and psychosomatic symptoms related to mental health among mothers from a Spanish birth cohort. Our study was based on data from 1171 women participating in two follow-ups of a population-based cohort in Valencia, Sabadell, and Gipuzkoa (2004-2012). For each participant, residential surrounding greenspace was estimated as the average of the satellite-based Normalized Difference Vegetation Index (NDVI) across different buffers around the residential address at the time of delivery and at the 4-year follow-up. The Symptom Checklist 90 Revised (SCL-90-R) was applied to characterize mental health at the 4-year follow-up. We developed mixed-effects logistic regression models controlled for relevant covariates to evaluate the associations. Higher residential surrounding greenspace was associated with a lower risk of somatization and anxiety symptoms. For General Severity Index (GSI), obsessive-compulsive, interpersonal sensitivity, depression, hostility, phobic anxiety, paranoid ideation, and psychoticism symptoms, we generally observed protective associations, but none attained statistical significance. Findings from this study suggested a potential positive impactof greenspace on mental health.

Residential green space and child intelligence and behavior across urban, suburban, and rural areas in Belgium: A longitudinal birth cohort study of twins

BACKGROUND

Exposure to green space has beneficial effects on several cognitive and behavioral aspects. However, to our knowledge, no study addressed intelligence as outcome. We investigated whether the level of urbanicity can modify the association of residential green space with intelligence and behavior in children.

METHODS AND FINDINGS

This study includes 620 children and is part of the East Flanders Prospective Twin Survey (EFPTS), a registry of multiple births in the province of East Flanders, Belgium. Intelligence was assessed with the Wechsler Intelligence Scale for Children-Revised (WISC-R) in 620 children (310 twin pairs) between 7 and 15 years old. From a subset of 442 children, behavior was determined based on the Achenbach Child Behavior Checklist (CBCL). Prenatal and childhood residential addresses were geocoded and used to assign green space indicators. Mixed modeling was performed to investigate green space in association with intelligence and behavior while adjusting for potential confounding factors including sex, age, parental education, neighborhood household income, year of assessment, and zygosity and chorionicity. We found that residential green space in association with both intelligence and behavior in children was modified by the degree of urbanicity (p < 0.001). In children living in an urban environment, multivariable adjusted mixed modeling analysis revealed that an IQR increment of residential green space (3,000-m radius) was associated with a 2.6 points (95% CI 1.4-3.9; p < 0.001) higher total intelligence quotient (IQ) and 2.0 points (95% CI -3.5 to -0.4; p = 0.017) lower externalizing behavioral score. In children residing in a rural or suburban environment, no association was found. A limitation of this study is that no information was available on school location and the potential for unmeasured confounding (e.g., time spend outdoors).

CONCLUSIONS

Our results indicate that residential green space may be beneficial for the intellectual and the behavioral development of children living in urban areas. These findings are relevant for policy makers and urban planners to create an optimal environment for children to develop their full potential.

Residential greenspace and lung function up to 24 years of age: The ALSPAC birth cohort

BACKGROUND

Residing in greener areas is increasingly linked to beneficial health outcomes, but little is known about its effect on respiratory health.

OBJECTIVE

We examined associations between residential greenness and nearby green spaces with lung function up to 24 years in the UK Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort.

METHODS

Lung function was measured by spirometry at eight, 15 and 24 years of age. Greenness levels within circular buffers (100-1000 m) around the birth, eight-, 15- and 24-year home addresses were calculated using the satellite-derived Normalized Difference Vegetation Index and averaged (lifetime greenness). The presence and proportion of green spaces (urban green spaces, forests and agricultural land) within a 300 m buffer was determined. First, associations between repeated greenness and green space variables and repeated lung function parameters were assessed using generalized estimation equations (N = 7094, 47.9% male). Second, associations between lifetime average greenness and lifetime average proportion of green spaces with lung function at 24-years were assessed using linear regression models (N = 1763, 39.6% male). All models were adjusted for individual and environmental covariates.

RESULTS

Using repeated greenspace and lung function data at eight, 15 and 24 years, greenness in a 100 m buffer was associated with higher FEV₁ and FVC (11.4 ml [2.6, 20.3] and 12.2 ml [1.8, 22.7], respectively, per interquartile range increase), as was the presence of urban green spaces in a 300 m buffer (20.3 ml [-0.1, 40.7] and 23.1 ml [-0.3, 46.5] for FEV₁ and FVC, respectively). These associations were independent of air pollution, urbanicity and socio-economic status. Lifetime average greenness within a 100 m buffer and proportion of agricultural land within a 300 m buffer were associated with better lung function at 24 years but adjusting for asthma attenuated these associations.

DISCUSSION

This study provides suggestive evidence that children whose homes are in more vegetated places or are in close proximity of green spaces have better lung function up to 24 years of age.

Greater tree cover near residence is associated with reduced allostatic load in residents of central North Carolina

BACKGROUND

Among urban residents, increased contacts with nature are associated with reduced morbidity and mortality. The concept of allostatic load, a biomarker-based composite measure of physiological dysregulation, can be applied to study subclinical benefits of exposure, and to elucidate pathways leading to improved health.

OBJECTIVE

This research explored associations between residential vegetated land cover and an allostatic load index calculated using the statistical distance measure known as Mahalanobis distance.

METHODS

This cross-sectional population-based study involved 186 adult residents of the Durham-Chapel Hill, North Carolina metropolitan area. Measures of tree and grass cover within 500 m of residence were derived from the U.S. Environmental Protection Agency's EnviroAtlas land cover database. Fifteen biomarkers of immune, neuroendocrine, and metabolic functions were analyzed in serum samples. Regression analysis was conducted using generalized additive models with thin-plate spline functions of geographic coordinates, adjusting for modelled traffic air pollution from local sources and sociodemographic covariates.

RESULTS

The second and third tertiles of distance-weighted tree cover were associated with 14% (95% Confidence Limits 20%; 8%) and 15% (21%; 8%) reduction in adjusted median allostatic load, respectively, compared to the first tertile. The same tertiles of tree cover were also associated with 0.16 (0.03; 0.76) and 0.04 (0.01; 0.35) adjusted odds ratios of having allostatic load index above the 90th percentile of the sample distribution. Grass cover was inversely correlated with tree cover and was not associated with reduced allostatic load.

CONCLUSIONS

Subclinical beneficial health effects of green spaces demonstrated in this study are consistent with reduced susceptibility to acute environmental and social stressors, and reduced risks of morbidity and mortality.

Natural Categorization: Electrophysiological Responses to Viewing Natural Versus Built Environments

Environments are unique in terms of structural composition and evoked human experience. Previous studies suggest that natural compared to built environments may increase positive emotions. Humans in natural environments also demonstrate greater performance on attention-based tasks. Few studies have investigated cortical mechanisms underlying these phenomena or probed these differences from a neural perspective. Using a temporally sensitive electrophysiological approach, we employ an event-related, implicit passive viewing task to demonstrate that in humans, a greater late positive potential (LPP) occurs with exposure to built than natural environments, resulting in a faster return of activation to pre-stimulus baseline levels when viewing natural environments. Our research thus provides new evidence suggesting natural environments are perceived differently from built environments, converging with previous behavioral findings and theoretical assumptions from environmental psychology.

Green space and early childhood development: a systematic review

Background The urban environment presents significant health challenges for children, such as discouraging physical exercise and increasing exposure to air pollution, excessive noise and higher temperatures. Reducing exposures to these negative environmental factors can have great benefits on a child's well-being and lower their risk of developing chronic diseases later in life. There is increasing evidence that suggests that the presence of urban green space can offer benefits to human health and well-being. While studies have reported the impact green space exposure has on the individual health outcomes of children, few have paid attention to the link between green space and the child's development. This review aims to synthesise the evidence of the effect green space exposure has on early childhood development. Objectives To explore the relationship between green space and early childhood development. Methods An online search was conducted using pre-identified keywords related to green space and early childhood development using search engines such as PubMed, MEDLINE, Web of Science, MeSH and PsycINFO. Peer-reviewed papers published in the past 10 years were included in this review. Papers were selected, extracted, analysed and interpreted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results Fifty-one papers were identified, of which 28 were excluded due to duplications or irrelevance, yielding a total of 23 papers to be reviewed. Articles were categorised based on reported outcomes: perinatal health, physical health, psychological health and respiratory health. An increase in green space during pregnancy was associated with increased birth weight and a decreased risk for low birth weight (LBW). Further, higher greenness exposure during childhood was associated with increased levels of physical activity and a lower risk of obesity and neurodevelopmental issues such as inattentiveness. While green space exposure was negatively associated with wheezing and bronchitis in some cohorts, certain plant species increase asthmatic symptoms during childhood, indicating that plant species type is an important determinant. Conclusion The extant literature on green space exposure and early childhood development is small. Regardless, the existing research provides promising insights into the benefits of green space exposure on children's health and well-being in an ever-increasing urban world. Further research is needed on the causal relationships between both quantity and quality of green space to early childhood development.