Table 2.
Characteristics of the included systematic reviews with meta-analyses on green spaces and health (n = 34).
| Author | Year | Primary studies | Exposure | Outcome | Findings |
|---|---|---|---|---|---|
| Squillacioti et al.49 | 2024 | Six studies including two cohort studies and four cross-sectional studies | NDVI | Asthma | No overall significant association was observed between the NDVI assessed within 500-m buffers |
| Ahmer et al.47 | 2023 | 31 studies including 26 cross-sectional studies, three cohort studies, one case control study, and one quasi experimental study | NDVI | Birth weight, LBW, PTB, and SGA | Residential green spaces are positively associated with increased birth weight and lower odds of low birth weight, preterm births and SGA deliveries |
| Tang et al.50 | 2023 | 35 studies including 10 cross-sectional studies, 18 cohort studies, 4 ecological studies, and 3 case–control studies | NDVI | Incidence/prevalence of asthma, AR, COPD, and lung cancer, mortality of COPD and lung cancer | Increments in NDVI were significantly related to lower rates of asthma incidence, lung cancer incidence, and COPD mortality risk |
| Li et al. (a)48 | 2023 | 14 cohort studies | NDVI (multiple buffers) | Cancer incidence, prostate cancer incidence, lung cancer incidence, breast cancer incidence, cancer mortality, lung cancer mortality, colorectal cancer incidence, bladder cancer incidence, and skin cancer incidence | Greenspace exposure measured as NDVI reduces lung cancer and prostate cancer mortality, as well as prostate, lung, and breast cancer incidence |
| Li et al. (b)33 | 2023 | There were 27 longitudinal studies, seven cross-sectional studies, four ecological studies, four case–control studies, and two time-series studies | NDVI (multiple buffers) | Cerebrovascular diseases, neurodegenerative diseases, stroke mortality, Parkinson's disease incidence, and stroke prevalence/incidence | There existed significant and inverse relationships between the risk of nervous system disease mortality and incidence/prevalence and greenness levels |
| Liu et al.34 | 2023 | 18 cross-sectional studies | NDVI and the proportion of green space | Depression and anxiety | Higher green space exposure might be beneficial for depression and anxiety disorders |
| Wang et al.40 | 2023 | 48 studies including 19 cohort or longitudinal studies, 18 cross-sectional studies, seven ecological studies, and four case–control studies | NDVI | Allergic diseases including ever asthma, current asthma, AR, allergic rhino conjunctivitis, atopic dermatitis, and food allergy | Exposure to a greener environment at birth reduces the risk of asthma and AR in childhood, and higher greenness exposure decreased odds of current asthma in children |
| Briggs et al.16 | 2022 | 12 RCTs | Gardening intervention vs. non-gardening activities | Depression, anxiety, stress and health-related quality of life wellbeing | Gardening related interventions may increase wellbeing and reduce symptoms of depression |
| Meo et al.36 | 2022 | 16 studies including three cross-sectional, two longitudinal, and 11 cohort studies | Per interquartile range NDVI (multiple buffers) | Prevalence and mortality of type II diabetes mellitus | An interquartile range higher NDVI significantly decreased the prevalence and mortality of type II diabetes mellitus |
| Song et al.26 | 2022 | 24 RCTs consisted of 10 parallel studies and 14 crossover studies | Green space settings vs. non-green space settings | Fatigue, tension, confusion, vigour, depression, and anger from POMS; negative affect and positive affect from PANAS | Compared to non-green space situations, green space exposure was related to decreased negative feelings, increased pleasant emotions, and lower physiological indicators |
| Zhao et al.45 | 2022 | 38 articles (52 analysis) including 27 cross-sectional designs, 10 cohort studies, and one case–control study | NDVI, the proportion of greenspace, distance to greenspace | Systolic blood pressure, diastolic blood pressure, and hypertension | Higher NDVI was significantly associated with lower levels of systolic blood pressure and diastolic blood pressure, and higher proportion of greenspaces was associated with lower odds of hypertension |
| Kelley et al.23 | 2022 | Four pre-post matched groups studies | Physical activity in natural outdoor environment vs. indoors | Wellbeing | Physical activity in the natural outdoor environment was associated with higher wellbeing, but limited in superior benefits to that engaged indoors |
| Sakhvidi et al.43 | 2022 | 18 studies including six prospective and retrospective cohorts, four case–control, and eight cross-sectional studies | NDVI-300 m | Breast, lung, prostate, skin, all-site cancer, brain, mouth and throat incidence, and all-site cancers mortality | Greenspace could be a potential risk factor for skin cancer, but for the other cancers, the results were non-conclusive |
| Zagnoli et al.42 | 2022 | 12 studies including four cross-sectional studies, one case–control study, five cohort studies, one including both cross-sectional and cohort design study, and one ecological study | NDVI, land use/cover | Dementia, Alzheimer's disease and cognitive impairment | A slight inverse association between dementia and greenness at intermediate exposure levels, but not at high levels |
| Coventry et al.22 | 2021 | 50 studies including 16 RCTs, 18 controlled studies, and 16 uncontrolled before and after studies | Activities in outdoor green spaces vs. non-nature spaces | Physical health and/or mental health symptoms | Nature-based interventions were effective for improving depressive mood, reducing anxiety, improving positive affect, and reducing negative affect |
| Hu et al.20 | 2021 | 29 studies including 22 cross-sectional design, six cohort, and one case–control study | NDVI | Birth weight, preterm birth, SGA, LBW | An increase in NDVI was generally associated with higher birth weight and lower odds of LBW |
| Jia et al.29 | 2021 | 21 studies including four cohort studies and 17 cross-sectional studies | Access to green space | Children's BMI z-score, children's BMI, and risk of overweight/obesity | More access to green space was associated with lower BMI and weight status among children |
| Mygind et al.25 | 2021 | 26 studies including 16 experimental studies and seven quasi-experimental studies | Activities in natural environments vs. urban environments | HRV, serum and salivary cortisol, and salivary cortisol | Seated relaxing and walking in natural environments enhanced HRV more than the same activities in urban environments, but the associations were inconsistent for cortisol concentrations |
| Qiu et al.37 | 2021 | 33 studies including 18 cross-sectional studies, 11 cohort studies, and four case studies | NDVI (multiple buffers) | Allergic, respiration, LBW, CVD, obesity, mental health, and blood pressure | High-level residential greenness significantly decreased respiratory disease, LBW, CVD, obesity, mental disorders, and blood pressure |
| Yao et al.17 | 2021 | 31 studies including 20 randomized crossover studies, five nonrandomized crossover studies, three randomized parallel group studies, two factorial studies and one single-group crossover study | Exposure to the natural environment vs. built/urban environment | POMS, total mood disturbance, PANAS, state-trait anxiety inventory, semantic differential method, restorative outcome scale, SBP, DBP, HR, HRV, salivary cortisol | Increased natural exposure was associated with decreased levels of salivary cortisol, state-of anxiety, self-reported stress, SBP, DBP, HRV and increased odds of restorative outcomes |
| Zhao et al.46 | 2021 | Eight studies including four cohort, two case–control and two cross-sectional studies | Residential greenness (measured as NDVI, percentage of greenspace, availability of green environment [in km2/105 people], and the distance to nearest greenspace) | Cognitive impairment/dementia | Exposure to more greenness was protective for cognitive impairment and dementia |
| Kua et al.30 | 2021 | 20 studies including seven longitudinal cohort studies and 13 cross-sectional studies | NDVI | All-cause mortality | Increased levels of greenness exposure were associated with a significant decrease in all-cause mortality |
| Yao et al. (a)28 | 2021 | 20 studies including 12 mixed factorial studies, six between-subject studies and two within-subject studies | Exposure to the natural environment vs. built environment | Positive and negative affect | Exposure to the natural environment could increase positive affect and decrease negative affect |
| Yuan et al.41 | 2021 | Eight cohort studies | NDVI | Respiratory disease mortality, all-cause mortality, stroke mortality, CVD mortality, IHD mortality | Greater greenness exposure was associated with a reduced risk of all-cause mortality and stroke mortality in older individuals |
| Kotera et al.24 | 2020 | 20 studies including eight non-randomized trials and 12 randomized controlled trials | Shinrin-yoku (forest bathing) and nature therapy | Depression, anger, and anxiety | Shinrin-yoku was effective for reducing negative mental health symptoms, particularly anxiety |
| Lee et al.32 | 2020 | 21 studies including 7 cohort studies and 13 cross-sectional studies | NDVI | Term birth weight, birth weight, LBW, very low birth weight, SGA, and preterm delivery | Greater greenness levels were positively associated with birthweight and inversely associated with odds of LBW, SGA, and preterm delivery |
| Luo et al.35 | 2020 | 57 articles (67 analyses) including 46 cross-sectional studies and 11 cohort studies | NDVI, proximity to green spaces, proportion of greenspace, and number of parks | Overweight/obesity | Greater NDVI levels were associated with lower odds of overweight/obesity |
| Zhan et al.44 | 2020 | 36 studies including 14 cohort studies, two case–control studies, 19 cross-sectional studies, and one ecological study | NDVI, percentage of tree canopy, proximity to green spaces, green space percentage, and distance to nearest green spaces | Birth weight, LBW, SGA, PTB, gestational age and head circumference, and gestational diabetes mellitus | Compared mothers at the lowest greenness levels, those at the higher greenness levels had increased birth weight and head circumference levels as well as reduced odds of LBW, SGA, and mental disorders |
| Kunpeuk et al.31 | 2020 | 19 articles including 14 cross-sectional studies, four quasi-experimental studies and one case–control study | Gardeners vs. non-gardeners | BMI | Gardening was significantly associated with lower BMI levels |
| Weeland et al.27 | 2019 | 31 studies including 16 (Quasi-)experimental studies and 15 Correlational studies | Correlational studies: residential greenness vs. green-based activities (Quasi-)Experimental studies: exposure to nature vs. not exposure to nature | Self-regulation including cognitive, affective, and behavioural self-regulation | More exposure to nature was associated with better self-regulation both in correlational studies and experimental studies |
| Twohig-Bennett et al.39 | 2018 | 142 studies including 40 interventional studies and 102 observational studies (including 35 cohort studies, 69 cross-sectional studies, and 18 ecological studies) | Greenspace (assessed as neighbourhood greenspace, greenspace-based interventions, proximity to a large greenspace and comparing green environment with an urban or indoor environment) | Gestational age, PTB, SGA, DBP, SBP, CVD mortality, all-cause mortality, HR, coronary heart disease, HRV, stroke, type II diabetes, high density lipoprotein cholesterol, low density lipoprotein cholesterol, haemoglobin A1C, fasting blood glucose, total cholesterol, triglycerides, dyslipidaemia, salivary cortisol, asthma, and self-reported health | Increased greenspace exposure was associated with decreased levels salivary cortisol, HR, DBP, high density lipoprotein cholesterol, low frequency HRV, PTB, type II diabetes, all-cause mortality, SGA, cardiovascular mortality, stroke incidence, hypertension, dyslipidaemia, asthma, coronary heart disease, and bad self-reported health, as well as increased high frequency HRV |
| Sadoine et al.38 | 2018 | 11 observational studies | NDVI | Malaria risk | NDVI was not found to be significantly associated with malaria |
| Gascon et al.19 | 2016 | 12 articles including seven ecological design studies, three cohort studies, and two cross-sectional studies | Residential greenness (measured as the percentage of green space in an area or as NDVI) | CVD mortality, lung cancer mortality, and all-cause mortality | Higher residential greenness levels were associated with reduced risk of CVD |
| Bowler et al.21 | 2010 | 24 articles including 13 crossover trials, five observational studies, and seven comparison groups | Before vs. after activity in natural environments; natural vs. synthetic environment | Sadness, attention, anger, fatigue, energy, anxiety, tranquillity, systolic blood pressure, diastolic blood pressure, and cortisol concentrations | Exposure to natural environment was associated with reduced odds of anxiety, attention, and sadness |
Abbreviation: NDVI, normalized difference vegetation index; AR, allergic rhinitis; RCTs, randomized controlled trials; POMS, The Profile of Mood States; PANAS, Positive and Negative Affect Schedule; CVD, cardiovascular disease; IHD, ischemic heart disease; COPD, chronic obstructive pulmonary disease; SGA, small for gestational age infant; LBW, low birth weight; BMI, body mass index; HRV, heart rate variability; SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; PTB, preterm birth.