Urban green space, tree canopy and prevention of cardiometabolic diseases: a multilevel longitudinal study of 46 786 Australians

Abstract

Background Cross-sectional studies suggest that more green space may lower the odds of prevalent diabetes, hypertension and cardiovascular diseases (CVD) in cities. We assess if these results are replicable for tree canopy exposure and then extend the study longitudinally to examine incident cardiometabolic outcomes. Methods The study was set in the Australian cities of Sydney, Wollongong and Newcastle. Total green space and tree canopy as percentages of landcover within 1.6 km (1 mile) from home were linked to a residentially stable sample of 46 786 participants in the Sax Institute’s 45 and Up Study (baseline 2006–09; follow-up 2012–15). Separate multilevel models were used to investigate whether the odds of prevalent and incident doctor-diagnosed diabetes, hypertension and CVD were associated with total green space and tree canopy provision, adjusting for age, sex, income, education, employment and couple status. Results Lower odds of prevalent diabetes were observed with 1% increases in total green space [odds ratio (OR) 0.993, 95% confidence interval (CI) 0.988 to 0.998] and tree canopy (0.984, 0.978 to 0.989). Lower odds of prevalent CVD were found with a 1% increase in tree canopy only (0.996, 0.993 to 0.999). Lower odds of incident diabetes (0.988, 0.981 to 0.994), hypertension (0.993, 0.989 to 0.997) and CVD (0.993, 0.988 to 0.998) were associated with a 1% increase in tree canopy, but not total green space. At ≥30% compared with 0–9% tree canopy, there were lower odds of incident diabetes (0.687, 0.547 to 0.855), hypertension (0.828, 0.719 to 0.952) and CVD (0.782, 0.652 to 0.935). However, ≥30% compared with 0–4% total green space was associated with lower odds of prevalent diabetes only (0.695, 0.512 to 0.962). Conclusions Restoring local tree canopy in neighbourhoods may help to prevent the incidence of cardiometabolic diseases.

Association Between Residential Greenness, Cardiometabolic Disorders, and Cardiovascular Disease Among Adults in China

“…Although our study was cross-sectional and used NDVI levels to estimate exposure, our findings may support those from 2 prospective cohort studies 15 , 32 that used different green space measures and 1 natural experiment study. 18 The first cohort study followed up 5112 Lithuanian adults for 4.4 years.…”

“… 15 The second cohort study found that a larger tree canopy percentage was associated with a lower risk of incident CVD among 46 786 Australian adults. 32 In the natural experiment study, Donovan et al 21 analyzed longitudinal data from 156 146 women and examined the association between the loss of trees owing to an invasive forest pest and incident CVD. They reported that women living in areas with greater tree loss had an increased risk of CVD.…”

“…Accumulating data indicate that a higher amount of neighborhood vegetation (referred to as residential greenness) is associated with a range of beneficial health outcomes. 3 , 4 A large number of studies have examined the cardiovascular associations of greenness, 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 but more than 50% of those focused on CVD mortality. In addition, most of the previous studies were conducted in middle- and high-income countries, and only a few studies were performed in low-income countries.…”

Tree Canopy Cover Is Best Associated with Perceptions of Greenspace: A Short Communication

“…A large body of evidence has pointed towards a relationship between greenspace and physical or psychological health [ 1 , 2 , 3 ]. A number of metrics are used to quantify greenspace [ 4 , 5 ].…”

“…While NDVI measures overall “greenness”, discretely marked green zones such as parks may represent public open spaces. The amount of tree canopy in such buffers has recently been shown to be more salient to health than other forms of greenspace [ 1 ]. Finally, even GSV-based metrics may have to be based on an optimal buffer size within which green exposure is measured.…”