Different types of greenspace within urban parks and depressive symptoms among older U.S. adults living in urban areas

Access to greenspace in the form of urban parks is frequently used to study the mental health benefits of nature and may alleviate depression. However, there is a lack of research that considers the different types of vegetated and non-vegetated spaces that parks can provide. Our aim was to investigate whether different types of accessible park area, grassy; tree covered; and non-vegetated, were associated with depressive symptoms among older (≥50 years) urban US adults. We used interviews from the Health and Retirement Study spanning 2010 through 2016 as our primary data source. We calculated total grassy, tree covered, and non-vegetated park space accessible to participants using a comprehensive national database of US parks and a high resolution (10 m) landcover dataset. To measure depressive symptoms, we used the CESD-8 analyzed as a continuous scale. We used Poisson regression to estimate the percent difference in CESD-8 scores comparing quartiles of accessible park space. To control for confounding, we adjusted for sociodemographic characteristics, geography, and climate. Aggregated accessible park area was not substantively associated with depressive symptoms. However, having grassy park area near the home was associated with as much as 27 % fewer depressive symptoms. In contrast, non-vegetated park area was associated with up to 54 % more depressive symptoms. Our findings were robust to adjustment for air pollution, environmental noise, and artificial light at night. Different types of accessible park space may have disparate effects on mental health among older urban US adults.