Early childhood exposure to more green spaces linked to improved lung function

Key takeaways:

• Researchers observed significant increases in FEV₁ and FVC with normalized difference vegetation index rises in early childhood.
• No link was found between exposure to green spaces in pregnancy and lung function.

Among school-age children, residence near more green spaces in early childhood positively impacted lung function, according to results published in Environment International.

“Our findings highlight the importance of integrating green spaces into urban environments for better respiratory health, also in children,” Martine Vrijheid, PhD, co-director of the Environment and Health over the Lifecourse program at the Barcelona Institute for Global Health, said in a press release. “If the way cities are configured is a factor that contributes to inequality, urban planning that consciously contributes to alleviating inequity is important.”

In an individual-participant data meta-analysis of 10 European birth cohorts, Vrijheid and colleagues evaluated 35,407 school-age children and mother pairs to determine how exposure to green spaces in pregnancy and early childhood impacts children’s lung function.

Researchers used satellite data and maps to assess the residential normalized difference vegetation index (NDVI) at 300 m.

As Healio previously reported, children with increased exposure to nature during childhood had improved lung function in later life.

Across the 10 cohort studies, the lowest median NDVI value during pregnancy was 0.23, and the highest median value was 0.52. Similarly, the lowest median NDVI value during childhood was 0.26, whereas the highest was 0.57.

Researchers observed significant increases in FEV₁ z-scores (B = 0.06; 95% CI, 0.03-0.09) and FVC z-scores (B = 0.07; 95% CI, 0.04-0.09) per NDVI rises of 1 interquartile range (IQR) in early childhood.

Following multiple testing correction and adjustment for ambient air pollutants, researchers continued to find this outcome.

When divided based on sex, the link between green space exposure in childhood and lung function improvement was stronger in girls (FVC z-scores, B = 0.07; 95% CI, 0.03-0.12) vs. boys.

In terms of distance to green spaces during childhood, further distance from the home significantly reduced the child’s FVC z-score (B = –0.04; 95% CI, –0.07 to –0.02), and researchers wrote that this held true after Bonferroni correction.

Splitting the cohort according to socioeconomic status (SES) revealed that the above link was stronger among children with higher vs. lower SES backgrounds.

No significant link was found between exposure to green spaces in pregnancy and lung function or between distance to green spaces during pregnancy and lung function.

When evaluating whether asthma, wheezing, cardiometabolic outcomes (BMI and blood pressure) and neurodevelopmental outcomes (non-verbal intelligence and behavioral problems) are each linked to green space exposure, researchers did not find any consistent relationships in either the pregnancy or childhood period.

“Our understanding of how green spaces affect lung function is still incomplete,” Amanda Fernandes, MS, postdoctoral researcher at the Barcelona Institute for Global Health at the time of the study, said in the release.

“We know that green spaces reduce air pollution, which in turn affects respiratory health,” she continued. “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.”

Reference:

• Children living in greener neighborhoods show better lung function. https://www.isglobal.org/en/-/los-ninos-y-ninas-que-viven-en-barrios-mas-verdes-presentan-una-mejor-funcion-pulmonar. Published July 17, 2024. Accessed July 24, 2024.