Studies from around the world have looked for links between how much green space a neighbourhood has and the health of the resident population. We expect to find this link because evidence from experimental studies in the laboratory and field suggests that being in natural environments may reduce stress, enable recovery from fatigue, lower blood pressure and promote healing. Green spaces may also encourage physical activity, and social contact. However, not all studies find a link between green space and health; the relationship seems to vary by country, gender, socio-economic position and, importantly, by the measure of health used.
Until recently there had been very little work looking at the relationships between green space and health in Scotland specifically. On March 11th, results of the GreenHealth programme are being launched at a conference in Edinburgh. CRESH was part of GreenHealth, together with colleagues from several other institutions in Scotland including The James Hutton Institute and our friends at the OPENspace Research Centre. In this blog I am going to tell you about some of the results from our part of the work.
A key part of our work was to look at the link between how much green space a neighbourhood has, and its rates of mortality and morbidity. The graph below is typical of the results we found.
The graph shows the relationship between the amount of green space in urban neighbourhoods in Scotland, and the risk of mortality for working age men. The risk is shown relative to urban areas with the least amount of green space, and the further a bar extends below the horizontal axis, the lower the risk in that type of area. The risk of death excludes that from external causes such as traffic accidents or suicide. The graph shows that in England and Wales, the risk of mortality falls as the amount of green space in an urban neighbourhood increases but in Scotland, there’s no significant relationship.
We spent a long time looking at whether these relationships were different for men and women, for older, working and younger age people, for more and less urban areas, for richer and poorer groups, for deaths from cardiovascular and respiratory disease, for measures of self-reported illness, and for different definitions of green space and neighbourhood. We only found a significant, protective relationship between mortality and green space for working age men living in the poorest two income-deprivation quartiles. Among these working-age men, those resident in the greenest urban areas were about 16% less likely to die than those resident in the least green urban areas.
On the whole though, we found very little evidence supporting the idea that urban neighbourhoods with more green space also have lower rates of mortality and morbidity.
The absence of effects for women echoes findings in England and Wales, and is likely linked to gender differences in the frequency and type of green space use. Women are known to use green spaces less often than men. We have written about this in the past and you can read our paper about it here.
So – why don’t we see a strong link between how much green space there is in a neighbourhood in Scotland, and how healthy it is? It seems very unlikely that the beneficial biological and psychological processes which being in green space seem to trigger, just don’t happen to Scottish people. We may be different up here, but we’re not a different species…
We checked to see if our methods, or the data sets used might explain it, but we got the same results whichever data or method we tried. We could not allow for differences in the quality or types of urban green space within Scotland, and between England, Wales and Scotland, and it is possible that this is partly responsible; perhaps urban green spaces in Scotland are smaller, or less conducive to use. Perhaps the weather is so awful up here, that people just don’t want to go outside (though, it has been known to rain in Wales too…). We also wondered whether the so-called Glasgow effect was responsible, but we got the same pattern of results when we excluded Glasgow from the analysis.
Our best bet is that the Scottish population has a higher level of underlying poor health and risky behaviours such as smoking and drinking. The impact of green space on risk of mortality is, even in England, relatively weak. Any benefits of green space in urban Scotland may just be swamped by other things that damage health.
It’s not all bad news though. Whilst greener neighbourhoods might not be healthier in urban Scotland, the people who actually visit and use green spaces, whether for exercise, or just to get away from it all for a while, do seem to have better mental health and more life satisfaction, all else being equal We have published some of those results already and blogged about them too. We have more evidence that folk who do use green spaces reap health and wellbeing benefits, and will be blogging more about it once those studies are published.
In the meantime, the message is that park down the road will probably do you an awful lot more good if you actually visit it…