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TOPLINE
Exposure to more green space within 100 meters of a residence was associated with a lower risk for dementia among older adults in Sweden, according to a 16-year study. The protective effect was stronger in women and diminished for green space at larger distances from residences.
METHODOLOGY
- Researchers conducted a prospective cohort study using data from the SNAC-K study, following 2993 dementia-free participants aged 60 years or older from 2001 to 2018.
- A total of 477 participants developed clinically diagnosed dementia according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Text Revision criteria during a mean follow-up of 9.7 years.
- Residential green space was assessed longitudinally using the satellite-based Normalized Difference Vegetation Index within 100-meter, 250-meter, and 500-meter circular buffer zones surrounding individual residences between 1990 and 2018.
- Outcome measures included incident all-cause dementia diagnosed through extensive in-person clinical examinations by trained physicians, nurses, and psychologists, supplemented by data obtained from the Swedish National Cause of Death Register and clinical medical records.
- The analysis was adjusted for demographic factors (age, sex, education, socioeconomic status), health behaviors (smoking, physical activity), BMI, medication use, neighborhood household mean income, and environmental exposures, including particulate matter (PM2.5) air pollution, road traffic noise, and blue space access. Apolipoprotein E-epsilon 4 carrier status was tested as an effect modifier.
TAKEAWAY
- During follow-up, 16% of participants were diagnosed with dementia. The risk for dementia decreased by 21% for every IQR (0.18) increase in the 5-year exposure to green space within a 100-meter buffer zone (hazard ratio [HR], 0.79; 95% CI, 0.64-0.96).
- No significant associations were observed for the larger buffer zones of 250 or 500 meters.
- Green space exposure was linked to a lower risk for dementia among women (HR, 0.69; 95% CI, 0.54-0.89; Pinteraction = .082) but not among men.
IN PRACTICE
"Our findings provide empirical support for policy makers to preserve and improve urban greenspace in the immediate surroundings of residences as a potential resource for brain health and cognitive resilience in aging populations, in addition to its broader ecosystem services, environmental and public health benefits," the investigators wrote.
SOURCE
The study was co-led by Cecilia U.D. Stenfors, PhD, Stockholm University, Stockholm, Sweden, and Jing Wu, Care Sciences and Society, Karolinska Institute, Stockholm, Sweden. It was published online on September 28 in Alzheimer's & Dementia.
LIMITATIONS
The sample was restricted to an affluent urban area in Stockholm, limiting the generalizability of the findings. Additionally, the study did not explore complex interactions between multiple environmental factors.
DISCLOSURES
The study was funded by the Swedish Research Council for Health, Working Life and Welfare, Region Stockholm, Chinese Scholarship Council, Lindhés Advokatbyrå AB, and Swedish Ministry of Health and Social Affairs. The authors reported no relevant conflicts of interest.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
