27848
Green Space Exposure Predicts Anxiety and Conduct Problems in Youth with ASD
Exposure to green space confers an array of physical, mental, and health benefits. However, most studies examining relationships between green space, health, and well-being focus on adults, typically developing children, and children with ADHD. Currently, there is no research on the effects of green space on the mental health and behavior of youth with autism spectrum disorders (ASD).
Objectives:
We sought to determine whether green space exposure predicts decreases in the severity of co-morbid anxiety symptoms in children with ASD. We hypothesized that anxiety and conduct problems symptoms would be less severe for youth in settings dominated by “gray” space (e.g., roads, buildings) (H1) and less severe for youth in settings characterized by higher green space (H2).
Methods:
We used national Zip-code level data from the National Survey of Children’s Health (NSCH, 2012) and the National Land Cover Database (NLCD) to investigate connections between proximity to green space, gray space, and severity of anxiety and conduct problems (low versus moderate to high), in youth diagnosed with ASD) (n=1284). All analyses include weighted and stratified binary logistic regression models. Respectively, green space and grey space were quantified as the percentage of the tree canopy coverage and built environment at the Zip-code level; the NLCD and NSCH were merged and analyzed on-site at the Centers for Disease Control in Atlanta. All models statistically controlled for the following variables: Severity (low/moderate-high) of co- morbid intellectual disability, learning disability, attention deficit disorder, and autism symptoms; gender; federal poverty level; age bracket (early childhood, middle childhood, and adolescence); race/ethnicity (White, Black, Hispanic, Other); maternal education; insurance status (private, public, and none); and English Language status (English speaking, non-English speaking).
Results:
Results of the logistic regression models supported small effects of environmental variables on anxiety and conduct problem severity. Impervious surface (aOR = 1.03, p < .05) and tree canopy (aOR = 1.03, p < .05) significantly predicted higher odds of moderate to high levels of anxiety problems in youth with ASD, supporting H1 but refuting H2. Furthermore, tree canopy coverage was associated slightly lower odds of moderate to severe conduct problems (aOR = 0.98, p < .05), supporting H1; grey space was not associated with conduct problem severity refuting H2.
Conclusions:
Our study, the first of its kind to examine the relationship between nature exposure and anxiety and conduct problems in youth with ASD. Both impervious surface coverage and tree canopy coverage increased the risk of severe anxiety in youth with autism, who might experience the stress-reducing benefits of nature differently than their typically developing peers. Furthermore, proximity to green space predicted slightly lower odds of conduct problems. This analysis is limited primarily by its reliance on zip code level environmental variables and rough parent report estimates of anxiety and conduct problem severity. More research using objective diagnostic metrics at finer spatial scales would help to illuminate complex relationships between green space, anxiety, and conduct problems in youth with ASD.