Greenness near home tracked with less Parkinson's — and more Alzheimer's
A 220,000-person cohort found opposite associations for two neurodegenerative diseases depending on the type and distance of greenery. Two other February papers ask who can actually use it.
"Spend time in nature" is among the least controversial pieces of wellbeing advice in circulation, which is part of the problem: a recommendation nobody argues with rarely gets examined closely. Three papers published in February examine different pieces of it, and none of them supports the simple version.
Not all greenness, and not in the same direction
A prospective cohort study in Neurobiology of Disease used data from up to 220,000 participants with no neurodegenerative disorder at baseline to test whether residential greenness predicted incident Parkinson's disease, Alzheimer's disease or multiple sclerosis [s1]. Over a median 10.8 years of follow-up, 1,211 people developed Parkinson's, 1,054 Alzheimer's and 411 multiple sclerosis [s1].
The exposures were deliberately disaggregated — green space, natural environment and domestic garden, measured within different distances of the home — because these are not the same thing. A managed park, a stretch of unmanaged countryside and a back garden differ in what they contain and in how a resident uses them.
Higher greenness was associated with reduced Parkinson's risk, most strongly for natural environment within a 300-metre buffer (HR 0.537, 95% CI 0.312–0.92) and green space within a 1,000-metre buffer (HR 0.667, 0.458–0.972) [s1].
The Alzheimer's result went the other way. Green space within a 300-metre buffer was linked to increased Alzheimer's risk (HR 1.623, 1.007–2.615) [s1].
Both of those confidence intervals nearly touch 1. The Parkinson's estimate for the 300-metre natural environment has an upper bound of 0.92; the Alzheimer's estimate has a lower bound of 1.007. These are not robust findings, and a study reporting opposite directions for two diseases in the same population using the same exposure should be read as generating a hypothesis rather than settling one.
The stratified analyses point in a consistent direction, for what they are worth: the protective association with natural environment against Parkinson's was stronger among older participants and smokers, and the green-space associations were more pronounced among socioeconomically disadvantaged participants and those in high air pollution areas [s1]. Participants with high polygenic risk scores also showed reduced Parkinson's risk at both buffer distances [s1]. The authors' conclusion is appropriately narrow: different types and distances of greenness exposure may exert different influences on different neurodegenerative disorders [s1].
What none of this establishes is mechanism. Residential greenness correlates with air pollution, traffic noise, income, walkability and pesticide exposure — the last of which is the best-established environmental Parkinson's risk factor and moves in the opposite direction from most of the others.
Living near it is not the same as using it
The cohort study measures what is near a person's home. A study in BMJ Public Health measures whether they can get into it.
Using Natural England's People and Nature Survey — a nationally representative survey of English adults aged 16 and over, drawing on five months of data collected between November 2020 and March 2021 (n = 10,415) — the authors modelled the relationship between health-related barriers to green space use, chronic conditions and sociodemographic characteristics [s2]. The abstract also reports the structural equation model as n = 201, a figure that does not reconcile with the survey sample it describes; we report both numbers as published rather than reconciling them.
Respondents with progressive illnesses or physical disabilities were more likely to report multiple barriers as important, whereas respondents with arthritis or diabetes had no barriers they were more likely to report [s2]. Lack of disabled facilities was named as an important barrier by 32% of respondents with physical disabilities and 31% of those with progressive illnesses [s2]. Having no one to go with or to help was named by 34% of those with progressive illnesses (p = 0.001) [s2].
The barriers split into two kinds: physical, such as fatigue, and place-based, such as poorly maintained sites [s2]. The authors argue that fixing the place-based and support barriers — facilities, maintenance, companionship — would benefit all users, not only those reporting a condition [s2].
That is the part of the green-space literature that translates into something a council can act on, and it is the part that receives the least attention relative to cohort studies of residential greenness.
A screen instead
A third paper tests a substitute. In a three-group randomised trial in northern Taiwan, 120 community-dwelling adults aged 65 and over were assigned to a single 20-minute exposure to virtual nature, actual nature or an actual urban environment [s3].
Compared with the urban group, the virtual-nature group improved more on attentional capacity measured by digit span (B = 1.00, 95% CI 0.19–1.80; P = .02), on positive affect (B = 2.82, 0.02–5.62; P = .048) and on negative affect (B = −2.22, −4.05 to −0.39; P = .02) [s3]. The actual-nature group improved on positive affect versus urban (B = 3.92, 1.65–6.19; P = .001) but did not show a significant attention effect [s3]. No physiological stress indicators showed significant group-by-time interactions, and no adverse events were reported [s3].
This is a single 20-minute session with immediate post-testing, and the authors say larger multisession trials with longer follow-up are needed to know whether anything persists [s3]. The result to take from it is modest and specific: for older adults who cannot easily reach real nature, a virtual substitute produced measurable short-term mood and attention changes, and did not produce the physiological changes often invoked to explain nature's benefits.
What to watch
The useful next question is not whether nature is good for people. It is whether the exposures that cohort studies measure — satellite-derived greenness within an arbitrary radius — correspond to anything a person actually does. The barriers work suggests that for a substantial minority they do not [s2], which would attenuate any true effect toward the null in every cohort study that ignores use.
Sources
- [s1] Residential green space, natural environment, domestic garden, and the risk of Parkinson's disease: a prospective cohort study. Neurobiology of Disease, 25 February 2026. https://doi.org/10.1016/j.nbd.2026.107334
- [s2] Investigating health-related barriers to green space use, chronic health conditions and sociodemographic characteristics: a structural equation modelling approach. BMJ Public Health, 11 February 2026. https://doi.org/10.1136/bmjph-2025-003077
- [s3] Effects of a virtual reality-based natural environment intervention on attention and mood in community-dwelling older adults: randomized controlled trial. JMIR Aging, 25 February 2026. https://doi.org/10.2196/87861
Sources
- Residential green space, natural environment, domestic garden, and the risk of Parkinson's disease: a prospective cohort study — Neurobiology of Disease , February 25, 2026
- Investigating health-related barriers to green space use, chronic health conditions and sociodemographic characteristics: a structural equation modelling approach — BMJ Public Health , February 11, 2026
- Effects of a virtual reality-based natural environment intervention on attention and mood in community-dwelling older adults: randomized controlled trial — JMIR Aging , February 25, 2026
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