Two separate studies looked at the effects that greenery has on our health – finding that the greener our surroundings, the better.
Published in Environmental Pollution and Science of the Total Environment, the international research team looked at whether green space around schools, such as an area of grass or trees, was associated with lower blood pressure in children and if there was a link between community greenness and obesity in adults living in urban areas, respectively.
University at Albany Environmental Health Science professors Michael Bloom and Shao Lin, who worked on both studies led by Guanghui Dong at Sun Yat-sen University in China, explain that while previous studies have shown that exposure to green spaces may help protect against negative health outcomes, few studies have considered the associations between green space around schools and blood pressure among children.
For the study on blood pressure in children, the team recruited 9,354 children from 62 schools in northeastern China. The children were given a physical examination and a blood pressure test while their parents submitted a questionnaire to capture demographic information and data on environmental exposures. Greenness around each child's school was measured using satellite data.
Results indicated that the more green space there was around schools was consistently associated with lower systolic blood pressure and with lower odds of hypertension in children. The beneficial effects of greenness were even stronger for overweight and obese children.
For the study on the association between community greenness and obesity in adults living in urban areas, the team analyzed data on 24,845 adults in 33 urban communities in northeastern China. Participants completed a questionnaire about their demographic characteristics, lifestyle and diagnosed health problems while measurements of height, weight and waist circumference were obtained during a clinical exam. Community greenness was assessed by remote sensing data from satellites.
Analysis showed that greater amounts of green spaces in a community were associated with lower body mass index (BMI) and obesity. "In particular, the impacts appeared to be most substantial among women, older individuals and for those with lower household incomes," the authors write.
The authors note that China provides an ideal setting for exploring the health effects of greenness due to its rapid urbanization and dramatic increase in obesity rates combined with a sharp decline in green space and greater air pollution.
"Though these studies took place in China, similar associations are likely to occur in other parts of the world, such as US and other developing nations, as well," said Bloom and Lin. "Greenery appears to be an important tool to protect against several negative health conditions."
Xiao, X., et al. (2020) Greenness around schools associated with lower risk of hypertension among children: Findings from the Seven Northeastern Cities Study in China. Environmental Pollution. doi.org/10.1016/j.envpol.2019.113422.