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

Does exposure to nature make children more intelligent? : analysis in Polish children with and without ADHD

Previous studies have shown that exposure to nature and physical activity (PA) may be associated with higher intelligence in children. We examined whether there is an association between lifelong exposure to greenspace and bluespace and intelligence in children aged 10–13 with and without attention deficit hyperactivity disorder (ADHD), and whether PA mediates this association. The sample (N = 714) was collected within the NeuroSmog case-control study, where children with (N = 206) and without ADHD (N = 508) were recruited from 18 towns in Southern Poland. Nature exposure was estimated as the sum of the z-scores of the objective and perceived measures. Objective greenspace exposure was defined as the percentage of grass and tree cover in 500 m and 1 km buffers around lifelong residential addresses, respectively. Objective bluespace exposure was defined as the percentage of water cover in 500 m and 1 km buffers. Perceived greenspace/bluespace was measured as the parent-rated availability, quality, and use of greenspace/bluespace. Intelligence was assessed using the Polish version of the Stanford-Binet Intelligence Scales, 5th edition (SB5). SB5 Full Scale Intelligence Quotient (IQ), Nonverbal IQ, Verbal IQ, five factor and ten subtest scores were analysed as outcomes. The associations between nature and IQ scores were assessed by linear regressions separately for cases and controls, adjusting the models for sex, parental education, and urbanicity. Structural equation modeling was implemented to test whether PA mediated the association between nature and intelligence. None of the greenspace or bluespace measures were consistently associated with intelligence. PA was not found to be a mediator. We did not find evidence that higher lifelong nature exposure is associated with higher intelligence in Polish schoolchildren with or without ADHD. This casts doubts on whether exposure to nature has relevant influence on IQ

Air pollution and attention in Polish schoolchildren with and without ADHD

Background: Development and functioning of attention—a key component of human cognition—can be affected by en vironmental factors. We investigated whether long- and short-term exposure to particulate matter with aerodynamic diameter < 10 μm (PM10) and nitrogen dioxide (NO2) are related to attention in 10- to 13-year-old children living in Polish towns recruited in the NeuroSmog case-control study. Methods: We investigated associations between air pollution and attention separately in children with attention deficit hyperactivity disorder (ADHD, n = 187), a sensitive, at-risk population with impaired attention and in population based typically developing children (TD, n = 465). Alerting, orienting, and executive aspects of attention were mea sured using the attention network test (ANT), while inhibitory control was measured with the continuous performance test (CPT). We assessed long-term exposure to NO2 and PM10 using novel hybrid land use regression (LUR) models. Short-term exposures to NO2 and PM10 were assigned to each subject using measurements taken at the air pollution monitoring station nearest to their home address. We tested associations for each exposure-outcome pair using adjusted linear and negative binomial regressions. Results: We found that long-term exposures to both NO2 and PM10 were associated with worse visual attention in chil dren with ADHD. Short-term exposure to NO2 was associated with less efficient executive attention in TD children and more errors in children with ADHD. It was also associated with shorter CPT response times in TD children; however, this effect was accompanied by a trend towards more CPT commission errors, suggestive of more impulsive performance in these subjects. Finally, we found that short-term PM10 exposure was associated with fewer omission errors in CPT in TD children. Conclusions: Exposure to air pollution, especially short-term exposure to NO2, may have a negative impact on attention in children. In sensitive populations, this impact might be different than in the general population

Sex Similarities and Differences in Intelligence in Children Aged Two to Eight: Analysis of SON-R 2–8 Scores

The aim of this study was to investigate sex similarities and differences in visuospatial and fluid abilities and IQ scores based on those abilities in children aged two to eight. Standardization data from the Snijders-Oomen Nonverbal Intelligence Test for Children aged 2&ndash;8 (SON-R 2&ndash;8) were used. A representative sample composed of 965 children from the Netherlands and 762 children from Germany was examined. Small but significant mean sex differences favoring girls were observed until age four. At ages six and seven, boys achieved similar cognitive development levels to girls regarding all abilities assessed and outperformed girls on the Mosaics subtest measuring visuospatial cognition. Boys also displayed higher variability rates in performance. The distribution of IQ scores, with the overrepresentation of girls scoring above mean and the overrepresentation of boys scoring below mean in early childhood, altered with age towards parity between the sexes. The results suggest that girls tend to mature earlier with respect to cognitive abilities. During the course of development, however, the differences between girls and boys may become negligible

Sex Similarities and Differences in Intelligence in Children Aged Two to Eight: Analysis of SON-R 2–8 Scores

The aim of this study was to investigate sex similarities and differences in visuospatial and fluid abilities and IQ scores based on those abilities in children aged two to eight. Standardization data from the Snijders-Oomen Nonverbal Intelligence Test for Children aged 2&#8722;8 (SON-R 2&#8722;8) were used. A representative sample composed of 965 children from the Netherlands and 762 children from Germany was examined. Small but significant mean sex differences favoring girls were observed until age four. At ages six and seven, boys achieved similar cognitive development levels to girls regarding all abilities assessed and outperformed girls on the Mosaics subtest measuring visuospatial cognition. Boys also displayed higher variability rates in performance. The distribution of IQ scores, with the overrepresentation of girls scoring above mean and the overrepresentation of boys scoring below mean in early childhood, altered with age towards parity between the sexes. The results suggest that girls tend to mature earlier with respect to cognitive abilities. During the course of development, however, the differences between girls and boys may become negligible

Association of residential and school green- and bluespace with academic performance in 10-13-year-old Polish schoolchildren with and without attention deficit hyperactivity disorder

Background: Several studies, mostly based on the USA data, have reported that school greenspace was associated with better academic performance. However, nearly all of them were conducted on aggregated data. We are among the first individual data-based studies worldwide to examine whether exposure to school and residential green- and bluespace can boost academic performance. Methods: NeuroSmog is an ongoing case-control study investigating the impact of air pollution on brain development in children with and without attention deficit hyperactivity disorder (ADHD). 658 children aged 10 to 13 years from 18 large and small towns in southern Poland constituted the analytical sample. Information about latest end-of-year school grades in Polish and maths was collected by the parent report while perceived academic performance in these subjects was collected by the Youth Self-Report. Tree, grass, and water cover, as well as overall vegetation, were abstracted in Euclidean buffers of 500 and 1000 m around concurrent school and residential addresses. Perceived green- and bluespace data were also collected. Adjusted for age, sex, parent education, financial situation, and urbanicity, logistic models were fitted to assess the asso ciations between each exposure-outcome pair. Result: We found no consistent associations between academic performance and school or residential green- and bluespace. This held true for children with and without ADHD. Conclusions: Higher residential and school green- and bluespace do not seem to be sufficient for better academic performance