Urban greenspace and dementia: Measures, mechanisms, and methodological guidance.

Urban greenspace has been associated with improved cognition and reduced Alzheimer's disease (AD) and AD-related dementias (ADRD) risk, but findings remain mixed, study quality varies, and evidence is largely cross-sectional. To advance the field, we offer guidance to select and apply greenspace exposure measures in AD/ADRD research. Our interdisciplinary expert working group synthesized existing knowledge and developed consensus-based recommendations through collaborative discussion. In this paper, we outline hypothesized pathways, summarize data sources and measurement approaches, and propose criteria and recommendations to select and apply greenspace exposure measures in research. Based on hypothesized pathways, we recommend tree canopy cover for stress reduction, attention restoration, and improved mental health; parks for increased physical and social activity; and greenness for reduced harmful exposures, highlighting the Normalized Difference Vegetation Index as capturing multiple pathways. We also identify future research priorities to advance understanding of greenspace-AD/ADRD associations and support more rigorous, comparable, and policy-relevant evidence.