Seite - 127 - in Biodiversity and Health in the Face of Climate Change

127 green spaces is very scarce (Markevych et  al. 2014b, 2016; Thiering et  al. 2016). A cross- sectional study of 10-year-old children in Germany reported higher blood pressure in children living in less green areas (Markevych et  al. 2014b). A longitu- dinal study following the same cohort of children for 5 years did not find any asso- ciation between residential green spaces and blood lipids (Markevych et  al. 2016). Very recently, a study of a population-based sample of around 4,000 school children in Iran found a beneficial association between time spent in green spaces and fasting blood glucose levels (Dadvand et al. 2018b). These findings were in line with those of an earlier German study that reported an inverse association between residential green spaces and insulin resistance (Thiering et  al. 2016). Further studies are required to investigate the effects of green spaces on cardiometabolic risk factors such as sedentary behaviour, obesity, dyslipidemia, hyperglycaemia and hypertension. 6.7 Final Remarks Currently, about half of the world’s population lives in cities (UN Department of Economic and Social Affairs 2015). By 2050, almost two-thirds of the global popu- lation are projected to live in urban areas (UN Department of Economic and Social Affairs 2015). Urban dwellers often have higher exposure to environmental hazards, limited access to green spaces, and a more sedentary and stressful lifestyle. Not surprisingly, urban children have been reported to be more likely to suffer from neurodevelopmental problems such as ADHD and autism spectrum disorders than rural children (Skounti et al. 2007; Williams et  al. 2006). An accumulating body of evidence supports the potential of green spaces for mitigating and buffering the adverse impacts of urban living on child health and development. So far, green spaces have been consistently associated with brain development and foetal growth. The available evidence for preterm birth, obesity, respiratory and allergic conditions has remained relatively inconsistent. Similarly, while there is heterogeneity in the reported associations between access to green spaces and physical activity, available studies suggest higher levels of physical activity while the children are in green spaces. Few studies exist for other outcomes such as dyslipidemia, hyperglycaemia, hypertension and pregnancy complications (e.g. pre-eclampsia or diabetes). Moreover, to date, the vast majority of the studies on the effects of green spaces on child health and development have been conducted in high-income countries. As ethnicity, climate and lifestyle might modify such effects, the generalisability of studies from these countries to the rest of the world could be limited. There is a need for more studies in low- and middle-income countries. Although further research is needed, all in all, the body of evidence on the effects of green spaces on child health and development highlights the importance of providing children with a natural and biodiverse environment, enabling them to better grow and thrive in our rapidly urbanising world. 6 Green Spaces and  Child Health and  Development