Although studies have demonstrated the beneficial effects of green spaces on general well being, the benefits of urban green spaces on Alzheimer’s disease (AD) are still unclear. In this retrospective cohort study, we sought to ascertain the connection between the presence of green spaces in urban environments and risk of AD.
The study sample comprised 294,983 participants, aged 40–74 years, and was derived from the Korean National Health Insurance Service National Sample Cohort. We used data of area (m2) and amount of artificial parks in 2005, provided by the Ministry of Land, Infrastructure and Transport. Starting from 2009, after removing those who received a dementia diagnosis within 1–3 years of gathering the index data, participants received follow-up AD testing. The Cox proportional-hazards model was utilized to establish the adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) of AD risk, based on the amount of urban green space area.
Compared to the quartile with the least amount of green space, participants in the highest urban space quartile had a reduced risk of receiving an AD diagnosis (aHR 0.84, 95% CI 0.72–0.99). The mediating effect of green space presence on AD was stronger among those in higher household income brackets (aHR 0.80, 95% CI 0.65–0.99), with more comorbidities (aHR 0.78, 95% CI 0.64–0.96), and without disabilities (aHR 0.82, 95% CI 0.69–0.97).
Living in urban areas with increased green space coverage may ultimately result in a lower risk of being diagnosed with AD. Urban planning strategies capable of boosting the total coverage of urban green space may assist in reducing AD risk.