Greener spaces equal better lung function for children, study finds

There’s a strong link between green urban spaces and respiratory health in childhood, a new meta-analysis has found. 

Researchers looked at the experiences of 35,000 children from eight European countries finding a “robust” link between exposure to green spaces in early childhood and better lung function. 

Led by the Barcelona Institute for Global Health (ISGlobal) 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,” first author Amanda Fernandes said.

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”, Ms Fernandes added.

Researchers hope their findings will reinforce 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”, lead author Martine Vrijheid added.

Access the findings in full here.