PURPOSE
Exposure to nature and natural environments may be beneficial for mental health; however, most population-based studies have been conducted among adults whereas few have focused on adolescents. We aimed to investigate the relationship between both greenness (vegetation) and blue space (water), and depressive symptoms among teenagers in the United States.
METHODS
The study population included 9,385 participants ages 12-18 in the 1999 wave of the Growing Up Today Study. We characterized greenness exposure using the Normalized Difference Vegetation Index at a 250-m and 1,250-m radius around a subject's residence using data from the moderate-resolution imaging spectroradiometer onboard the National Aeronautics and Space Administration's Terra satellite. Exposure to blue space was defined as the presence of blue space within a 250-m and 1,250-m radius and distance to the nearest blue space. We used logistic regression models to examine associations with high depressive symptoms, measured using self-reported responses to the McKnight Risk Factor Survey.
RESULTS
An interquartile range higher peak greenness in the 1,250-m buffer was associated with 11% lower odds of high depressive symptoms (95% confidence interval .79-.99). Although not statistically significant, this association was stronger in middle school students than in high school students. No such association was seen for blue spaces.
CONCLUSIONS
Surrounding greenness, but not blue space, was associated with lower odds of high depressive symptoms in this population of more than 9,000 U.S. adolescents. This association was stronger in middle school students than in high school students. Incorporating vegetation into residential areas may be beneficial for mental health.