RESUMEN
Background Evidence on the association between greenness and adiposity in children and adolescents is inconsistent and mostly from developed countries. Relatively limited evidence is from China. Objective To assess the association between greenness and adiposity in children and adolescents based on satellite remote sensing data. Methods From 2016 to 2018, a cross-sectional study was conducted among 52316 children and adolescents aged 5-18 years in three cities in the Pearl River Delta region of China. Basic sociological and demographic characteristics of the population and adiposity levels were collected through questionnaires. Land Remote-Sensing Satellite (Landsat) data and moderate-resolution imaging spectroradiometer (MODIS) products were used to quantify the greenness around the schools and homes, including normalized difference vegetation index (NDVI), vegetation continuous field (VCF), soil-adjusted vegetation index (SAVI), and enhanced vegetation index (EVI) calculated within 500 m and 1000 m buffers centered around the participants' homes or schools. A restricted cubic spline function was used to assess the exposure-response relationship. After categorizing greenness levels into quartiles with the first quartile as the reference, two-level generalized linear models were applied to assess the change in body mass index z-scores (zBMI) and the risk of overweight of children and adolescents in higher quartiles relative to the lowest quartile. In addition, counterfactual framework modelling was applied to assess the potential mediation effects of PM2.5 and NO2, and physical activity levels on the associations between greenness and adiposity levels. Results Of the 52316 children included, 8406 (16.1%) were overweight. A non-linear negative association of the level of greenness around the homes or schools and zBMI was found, with a significant lower zBMI in children and adolescents when a certain level of greenness was reached. After adjusting for confounders, the participants in the highest quartile had a significantly lower level of zBMI and a significantly lower risk of overweight compared with those in the lowest quartile of NDVI500 m and VCF500 m. The estimate change (\begin{document}$b$\end{document}) for zBMI was −0.07 (95%CI: −0.10-−0.04) and the odds ratio (OR) for overweight was 0.92 (95%CI: 0.85-0.99) for the students in the highest NDVI500 m quartile based on home address compared to those in the lowest quartile. Significant negative associations were also observed when 1000 m buffer, SAVI, and EVI were used. The mediation analysis showed that PM2.5 and NO2 partially mediated the negative association of NDVI500 m with zBMI , and the proportions of mediation were 50% (95%CI: 20%-80%) and 90% (95%CI: 50%-160%), respectively while no significant mediation effect was observed for physical activity level. Conclusion Higher levels of greenness surrounding homes or schools may be associated with a reduced risk of overweight and decreased zBMI in children and adolescents, and such associations may be partially mediated by reducing air pollutant concentrations.
RESUMEN
Background Studies on the association between greenness exposure and allergic rhinitis (AR) in children are mostly conducted in developed countries, and the conclusion is not consistent. Objective Using street view data to explore the association between greenness exposure and allergic rhinitis (AR) prevalence in Chinese children. Methods A cross-sectional study was conducted among 40868 children aged 2-17 years in three cities of Northeast China from 2012 to 2013, which consisted of 20886 (51.1%) boys and 19982 (48.9%) girls. The information of AR prevalence was obtained through questionnaire. Based on downloaded street view images from Tencent Maps, a green view index (GVI) of green vegetation (trees and grass) within 800 m and 1000 m buffer of the participants' schools was calculated by using artificial intelligence, and it was used as a surrogate of the greenness exposure. A mixed-effect logistic regression model was used to estimate the odds ratio (OR) of AR prevalence in children for per increase of inter-quartile range (IQR) of GVI. In addition, according to ambient PM2.5 concentration, the participants were divided into a low PM2.5 exposure group (≤56.23 μg·m−3) and a high exposure group (>56.23 μg·m−3) to investigate whether PM2.5 was a modifier on the association between GVI and AR. Results The average age of the subjects was (10.40±3.68) years and 3 963 (9.7%) subjects reported diagnosed AR. Within 800 m buffer, an IQR increase in GVI for trees (IQR=0.031, OR=0.85, 95%CI: 0.81-0.90) and overall greenness (IQR=0.029, OR=0.86, 95%CI: 0.81-0.90) was associated with lower adjusted odds ratio of AR. The interaction between PM2.5 and GVI was statistically significant (P< 0.1), that is, the negative associations of trees and overall greenness with AR were observed only at low PM2.5 exposure levels. The sensitivity analysis results of GVI within 1000 m buffer was consistent with that within 800 m buffer. Conclusion Exposure to green vegetation, especially trees, may be associated with decreased risks of AR in children, and such associations may be more obvious in areas with a low PM2.5 concentration.
RESUMEN
Abstract:Remote sensing and traditional ecological knowledge (TEK) can be combined to advance conservation of remote tropical regions, e.g. Amazonia, where intensive in situ surveys are often not possible. Integrating TEK into monitoring and management of these areas allows for community participation, as well as for offering novel insights into sustainable resource use. In this study, we developed a 250 m resolution land-cover map of the Western Guyana Shield (Venezuela) based on remote sensing, and used TEK to validate its relevance for indigenous livelihoods and land uses. We first employed a hyper-temporal remotely sensed vegetation index to derive a land classification system. During a 1 300 km, eight day fluvial expedition in roadless areas in the Amazonas State (Venezuela), we visited six indigenous communities who provided geo-referenced data on hunting, fishing and farming activities. We overlaid these TEK data onto the land classification map, to link land classes with indigenous use. We characterized land classes using patterns of greenness temporal change and topo-hydrological information, and proposed 12 land-cover types, grouped into five main landscapes: 1) water bodies; 2) open lands/forest edges; 3) evergreen forests; 4) submontane semideciduous forests, and 5) cloud forests. Each land cover class was identified with a pulsating profile describing temporal changes in greenness, hence we labelled our map as "The Forest Pulse". These greenness profiles showed a slightly increasing trend, for the period 2000 to 2009, in the land classes representing grassland and scrubland, and a slightly decreasing trend in the classes representing forests. This finding is consistent with a gain in carbon in grassland as a consequence of climate warming, and also with some loss of vegetation in the forests. Thus, our classification shows potential to assess future effects of climate change on landscape. Several classes were significantly connected with agriculture, fishing, overall hunting, and more specifically the hunting of primates, Mazama americana, Dasyprocta fuliginosa, and Tayassu pecari. Our results showed that TEK-based approaches can serve as a basis for validating the livelihood relevance of landscapes in high-value conservation areas, which can form the basis for furthering the management of natural resources in these regions. Rev. Biol. Trop. 64 (4): 1661-1682. Epub 2016 December 01.
Resumen:La teledetección y el conocimiento ecológico tradicional (CET) se pueden combinar para avanzar en la conservación de regiones tropicales remotas como la Amazonía, donde la toma de datos intensiva in situ a menudo es imposible. Integrar el CET en el seguimiento y el manejo de estas áreas permite la participación de la comunidad, y ofrece nuevos puntos de vista sobre el uso sostenible de los recursos naturales. En este estudio se desarrolla un mapa de cobertura del suelo del Escudo Guayanés (Venezuela), con una resolución espacial de 250 m, basado en datos de teledetección, y se utiliza el CET para validar su relevancia en relación con la subsistencia de los pueblos indígenas y el uso que éstos hacen del territorio. En primer lugar se ha empleado un índice de vegetación basado en teledetección hiper-temporal para realizar una clasificación del territorio. Durante una expedición fluvial de 8 días, a lo largo de 1 300 km por áreas sin carreteras en el Estado Amazonas (Venezuela), se han visitado seis comunidades que han proporcionado datos geo-referenciados sobre sus actividades cinegéticas, pesqueras y agrícolas. Estos datos de CET se han superpuesto al mapa de clasificación, con el fin de relacionar las clases de coberturas con los usos indígenas. Se han caracterizado las clases de cobertura en función de patrones de cambio temporal del verdor y la topo-hidrografía, y se han propuesto 12 tipos de cobertura del suelo, agrupadas en cinco tipos principales de paisaje: 1) masas de agua; 2) campo abierto/ márgenes del bosque; 3) bosques siempre-verdes; 4) bosques semi-caducifolios submontanos; y 5) bosques nublados. Cada clase de cobertura del suelo se ha identificado con un perfil pulsátil que describe cambios temporales en el verdor, de ahí que el mapa haya sido titulado "El Pulso del Bosque". Estos perfiles de verdor han mostrado una tendencia ligeramente ascendente, durante el periodo 2000 a 2009, en las clases que representan pastizales y zonas de matorral, así como una tendencia ligeramente decreciente en las clases que representan bosques. Este hallazgo es compatible con la ganancia de carbono en los pastizales como consecuencia del calentamiento del clima, y también con una cierta pérdida de vegetación en los bosques. De este modo, nuestra clasificación muestra potencial para la evaluación de efectos futuros del cambio climático sobre el paisaje. Algunas clases han resultado estar significativamente relacionadas con la agricultura, la pesca, la caza como práctica general, y más concretamente con la caza de primates, de Mazama Americana, Dasyprocta fuliginosa, y Tayassu pecari. Los resultados demuestran la utilidad de las aproximaciones basadas en CET como base para validar la importancia del paisaje, en áreas con alto valor de conservación, para la supervivencia de las personas, lo que proporciona una base para avanzar en el manejo de los recursos naturales en estas regiones.