Wu Jianyong, Jackson Laura
Oak Ridge Institute for Science and Education, US EPA, Office of Research and Development, Research Triangle Park, Durham, NC 27711, USA.
US EPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, Durham, NC, USA, 27711.
Environ Int. 2017 Oct;107:140-146. doi: 10.1016/j.envint.2017.07.010. Epub 2017 Jul 20.
Green space has a variety of health benefits. However, little is known about its impact on autism, the fastest-growing neurodevelopmental disorder in children. This study examined the relationship between green space and childhood autism prevalence. Autism count data in 2010 were obtained for 543 of ~560 public elementary school districts in California. Multiple types of green space were measured in each school district, including percentages of forest, grassland, and average tree canopy and near-road tree canopy. Their associations with autism prevalence were evaluated with negative binomial regression models and spatial regression models. We observed inverse associations between several green space metrics and autism prevalence in school districts with high road density, the highly urbanized areas, but not in others. According to negative binomial regression models, adjusted rate ratios (RR) for the relationships in these school districts between autism prevalence and green space metrics in 10% increments were as follows: for forest, RR=0.90 (95% confidence interval [CI]: 0.84-0.95); for grassland, RR=0.90 (95% CI: 0.83-0.97); for average tree canopy, RR=0.89 (95% CI: 0.83-0.95), and for near-road tree canopy, RR=0.81 (95% CI: 0.73-0.91). These results suggest that increases of 10% in forest, grassland, average tree canopy and near-road tree canopy are associated with a decrease in autism prevalence of 10%, 10% 11% and 19%, respectively. In contrast, urban land and road density were positively associated with autism prevalence. The results of spatial regression models were consistent with those obtained by negative binomial models, except for grassland. Our study suggests that green space, specifically tree cover in areas with high road density, may influence autism prevalence in elementary school children beneficially. Further studies are needed to investigate a potential causal relationship, and the major mechanisms that may underlie the beneficial associations with green space, such as buffering traffic-related air pollution and noise.
绿地对健康有多种益处。然而，对于绿地对自闭症（儿童中增长最快的神经发育障碍）的影响，人们却知之甚少。本研究考察了绿地与儿童自闭症患病率之间的关系。获取了加利福尼亚州约560个公立小学学区中543个学区2010年的自闭症计数数据。在每个学区测量了多种类型的绿地，包括森林、草地的百分比以及平均树冠覆盖率和道路附近树冠覆盖率。通过负二项回归模型和空间回归模型评估了它们与自闭症患病率的关联。我们观察到，在道路密度高的学区（即高度城市化地区），几种绿地指标与自闭症患病率呈负相关，而在其他地区则不然。根据负二项回归模型，在这些学区中，自闭症患病率与绿地指标以10%的增量变化时的调整率比（RR）如下：对于森林，RR = 0.90（95%置信区间[CI]：0.84 - 0.95）；对于草地，RR = 0.90（95% CI：0.83 - 0.97）；对于平均树冠覆盖率，RR = 0.89（95% CI：0.83 - 0.95），对于道路附近树冠覆盖率，RR = 0.81（95% CI：0.73 - 0.91）。这些结果表明，森林、草地、平均树冠覆盖率和道路附近树冠覆盖率分别增加10%，与自闭症患病率降低10%、10%、11%和19%相关。相比之下，城市土地和道路密度与自闭症患病率呈正相关。除草地外，空间回归模型的结果与负二项模型的结果一致。我们的研究表明，绿地，特别是道路密度高的地区的树木覆盖，可能对小学儿童的自闭症患病率产生有益影响。需要进一步研究来调查潜在的因果关系，以及与绿地有益关联的主要潜在机制，如缓冲与交通相关的空气污染和噪音。
