Green and Blue Space and Health
Reviews report green space associated with lower depression and anxiety (Liu 2023; Patwary 2022) and better mental health (Bryer 2024); Gascon 2015 finds limited evidence that the link is causal, and Noordzij 2021 finds no significant association in four ageing cohorts.
Water safety near blue space; heat and UV exposure in open areas.
- Environmental hazard at a local site (contamination, hazardous water): contact the local public-health/environmental authority
What the evidence says
The sources are systematic reviews, meta-analyses and an umbrella review of green space and mental health. Two of them do not support a causal or general link: Gascon 2015 (systematic review of 28 studies) found limited evidence for a causal relationship between surrounding greenness and adult mental health, and inadequate evidence in children, and Noordzij 2021 (pooled analysis of four European ageing cohorts) found no significant association with subjective health or depressed affect. Liu 2023 (meta-analysis) reports a 10% increase in green-space proportion linked to lower risk of depression and anxiety (OR 0.963), and concludes that the results support improving green-space exposure to prevent them. Patwary 2022 (meta-analysis of 72 studies) reports garden access associated with lower odds of depression (OR 0.71) and anxiety (OR 0.73). Bolanis 2023 (systematic review) concludes that preliminary findings suggest protective associations between greenspace and suicide-related outcomes. Marcham 2024 (systematic review) reports seven studies finding green-space exposure associated with reduced schizophrenia risk, five with a dose-response. Bryer 2024 (umbrella review of 36 reviews) reports beneficial effects for mortality, mental health and cognitive function and ambivalent results for cardiovascular, general and respiratory health, with most included reviews of low-to-moderate quality. Zhang 2021 (systematic review) reports the effect on mental well-being mediated by air quality, perceived stress and physical activity, with the mental-illness pathway equivocal. This block covers green space only; blue-space evidence is not carried here.
- Only large forests count, gardens and neighbourhood greenness are associated with benefits too
- The link is established as causal, Gascon 2015 found limited evidence for a causal relationship, and most of the evidence is associational
- Living near a park prevents disease
- Blue space heals medical conditions
- Agreement
- Direction recorded for 0 of 8 sources; not yet recorded for the rest.
- The claim's outcome
- Outcome not yet recorded
- Certainty
- No source states a certainty rating.
- How the sources were read
- Some sources are based on abstracts, not full texts.
What each source measured and concluded (8)
- What it measured
- Depression and anxiety outcomes in relation to green space exposure
- How it was read
- based on the abstract, not the full text
- What it measured
- Mental health outcomes (depression, anxiety, wellbeing)
- How it was read
- based on the abstract, not the full text
- What the review says it includes
- Systematic review with meta-analysis
- Studies and participants, as stated
- N=72 studies (from 2004 identified)
- What it measured
- Suicide-related outcomes (suicide mortality, self-harm, suicidal ideation)
- How it was read
- based on the abstract, not the full text
- What the review says it includes
- Systematic review
- Studies and participants, as stated
- N=23 studies (14 ecological, 4 cross-sectional, 3 longitudinal, 2 experimental)
- What it measured
- Incidence of schizophrenia and mental health outcomes (symptoms, health service use)
- How it was read
- screened only, not extracted
- What the review says it includes
- Systematic review (PRISMA; PROSPERO CRD42023431954)
- Studies and participants, as stated
- 12 studies eligible (126 screened)
- What it measured
- Association between greenspace exposure and health outcomes
- How it was read
- based on the abstract, not the full text
- What the review says it includes
- Systematic review of reviews (umbrella review)
- Studies and participants, as stated
- 36 systematic reviews
- What it measured
- Mental health benefits.
- How it measured it
- General Health Questionnaire (GHQ), Mental Health Inventory (MHI), Short Form health survey (SF) for adults; Strengths and Difficulties Questionnaire (SDQ), ADHD symptom criteria for children.
- Its conclusion, in its own words
- “We found limited evidence for a causal relationship between surrounding greenness and mental health in adults, whereas the evidence was inadequate in children.”
- How it was read
- read in full text
- What the review says it includes
- Systematic review of 28 studies
- Studies and participants, as stated
- N=not reported (range from ~100 to 345,143 participants) across 28 studies
- Heterogeneity, as stated
- Heterogeneity in exposure assessment
- What it measured
- Subjective health and depressed affect.
- How it measured it
- Self-reported indicators (self-report).
- Its conclusion, in its own words
- “Data from four European ageing cohorts provide no support for the hypothesis that green space exposure is associated with subjective health or depressed affect.”
- How it was read
- read in full text
- What the review says it includes
- Cross-sectional study with one-step individual participant data (IPD) meta-analysis of 4 cohorts
- Studies and participants, as stated
- N=16,189 participants across 4 studies
- What it measured
- Pathways/mediators linking greenspace exposure to mental health
- How it was read
- based on the abstract, not the full text
- What the review says it includes
- Systematic review of observational studies
- Studies and participants, as stated
- N=26 studies
Every source below is shown with its study design and links to the original study. This is the audit trail.
“Abstract only” means the review read that paper’s abstract, not its full text; “screened only” means it was included at re-screening and not extracted. Both stay in the trail with their DOI, because how a source was read is part of the audit.