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Greenspace may bring benefits to human health. Evidence on greenness and health has accumulated in western countries, and several reviews have summarized such evidence. Researchers have also conducted some studies on greenspace and human health in Chinese population, but no prior review has pooled or summarized them. To provide more comprehensive evidence on this topic, we searched and summarized studies on greenspace and health that were conducted specifically in Chinese population. We found that a certain number of studies have been conducted in China, and the evidence indicates that greenspace exposure may reduce the odds of cardiovascular diseases, mental health disorders, adverse birth outcomes as well as mortality. However, most of the current reported studies were of cross-sectional design or randomized controlled trails targeting short-term effects, and prospective cohort studies were scarce. Moreover, greenness exposure was mainly assessed using greenness index like normalized difference vegetative index (NDVI), which were static and cannot distinguish construction and species of greenspaces. Future prospective studies with more precise greenness exposure assessment are warranted to evaluate the prior findings.
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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.
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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.
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@#Mosquito control and "mosquito-free village" construction in rural areas played positive roles in preventing mosquito-borne diseases and improving rural living environments. However,there was a lack of the target and specific evaluation system for mosquito control and prevention in rural areas. Based on the main contents of mosquito control works in rural areas,the national standards for mosquito control and practical experiences for“mosquito-free village”construction in Zhejiang Province,we built a evaluation system suitable for mosquito control in rural areas,in order to provide reference for the evaluation standard and the sustainable development of mosquito control in rural areas. This evaluation system included four indices named mosquito density control,village administration,health education and the villagers' attitude;each index had three levels named A,B and C from high to low. When all the four indices were evaluated as C,the village was regarded as basically meeting the requirements of mosquito control;when all the four indices were evaluated as A,the village was regarded as a "mosquito-free village".