A recent large study found that exposure in childhood to more "green spaces" or a "greener neighborhood" results in better lung function in those children. Well, duh.. of course. The study needed to be done to show the health benefits of parks and other outdoor green spaces for children, and thus the need for green spaces in urban areas.
The study involved more than 35,000 children from eight European countries. They found that the more "green space" or "greener neighborhoods" exposure (meaning the more green spaces by the child's residence) that the children had in early childhood, the better it was for their lung function. On the other hand, the further away a child lived from green spaces, the lower the lung volume.
Why? The researchers point out that green spaces (parks, yards) reduce air pollution, which in turn affects respiratory health of children. It also exposes the children to beneficial microbes, which are good for their microbiome and immune system. Finally, playing outside (physical activity) is good for lung development and function.
From Science Daily: Children living in greener neighborhoods show better lung function
A large study of 35,000 children from eight countries has found a "robust" link between exposure to green spaces in early childhood and better lung function. The study, led by the Barcelona Institute for Global Health (ISGlobal), has been published in Environment International.
The research used data from 10 European birth cohorts from 8 countries (Denmark, France, Italy, Lithuania, Norway, the Netherlands, Spain and the UK) to conduct a meta-analysis. This assessment of the data was done at the individual level for each participant.
Data on exposure to green spaces were available from two different points in time: pregnancy and childhood (from 3 to 12 years of age). As a proxy for residential green space, the research team used the Normalised Difference Vegetation Index (NDVI) in a 300m buffer around the participant's address. NDVI is an index that uses satellite images to estimate the amount of vegetation at a given point.
Lung function was measured using spirometry tests. To assess lung volume, the researchers measured forced vital capacity (FVC), which is the maximum amount of air a person can breathe out without a time limit after taking a deep breath. And as an indicator of how open the airways are, forced expiratory volume in one second (FEV1) was taken. FEV1 is the volume of air exhaled in the first second of forced breathing after a deep inhalation.
Statistical analysis showed that children living in greener neighbourhoods had better lung function, specifically higher FVC and FEV1. On the contrary, those who lived further away from green spaces had a lower lung volume (FVC).
While the positive association of living in greener neighbourhoods with lung function was observed regardless of socioeconomic status, the effect was stronger in children from higher socioeconomic backgrounds. "One possible explanation could be that families with higher education or income may have access to higher-quality, safer, and better-maintained green areas" says Amanda Fernandes, first author and ISGlobal researcher at the time of the study.
Possible mechanisms
The researchers also looked at the mothers' home address during pregnancy, but in this case residential greenness was not associated with any of the indicators of respiratory health, suggesting that the link between green spaces and improved lung function has to do with something that happens in childhood.
"Our understanding of how green spaces affect lung function is still incomplete. We know that green spaces reduce air pollution, which in turn affects respiratory health. We also believe that green spaces may expose children to beneficial microbiota, which may contribute to the development of the immune system and indirectly influence lung function. Finally, green spaces close to home are likely to reflect the presence of play areas that encourage physical activity at an age when the lungs are still developing," says Amanda Fernandes.
"Our findings highlight the importance of integrating green spaces into urban environments for better respiratory health, also in children. If the way cities are configured is a factor that contributes to inequality, urban planning that consciously contributes to alleviating inequity is important," says Martine Vrijheid, lead author of the study and co-director of the Environment and Health over the Lifecourse programme at ISGlobal.
Health outcomes unrelated to green spaces
The study also looked at whether green spaces near the home during pregnancy and childhood were associated with other respiratory, cardiometabolic and neurodevelopmental outcomes, but found no other associations.