Precision residential greenspace, urban environmental exposures, and incident dementia among older adults in Sweden: A 16‐year cohort study

Abstract INTRODUCTION Residential greenspace is linked to mental and cardiometabolic health, but longitudinal studies on detailed greenspace and dementia incidence are limited. METHODS We followed 2993 dementia‐free participants in the Swedish National Study on Aging and Care Kungsholmen for 16 years; 477 developed clinically diagnosed dementia. Greenspace was assessed using normalized difference vegetation index within 100‐, 250‐, and 500‐m residential buffers. Cox models estimated hazard ratios (HRs) per interquartile‐range greenspace increment and tested effect modification by air pollution, road traffic noise, blue space, age, sex, and apolipoprotein E‐ε4 (APOE‐ε4). RESULTS Higher greenspace within 100 m was associated with lower dementia incidence (HR = 0.79, 95% confidence interval [CI] = 0.64–0.96), whereas associations for larger buffers were attenuated. Associations were stronger in women (HR = 0.69, 95% CI = 0.54–0.89) than men (HR = 0.93, 95% CI = 0.71–1.24). DISCUSSION Close residential greenspace may reduce dementia risk in older adults, particularly women.