Green spaces have often been synonymous with improved health and well-being, and for good reason. Parks, forests, and urban greenery offer a respite from the concrete jungle, bringing a host of environmental and psychological benefits. However, when it comes to respiratory outcomes among the youth in Europe, the influence of greenness still poses a conundrum. A recent systematic review and meta-analysis published in Environmental Research have made a noteworthy contribution to this continuing discussion, providing substantial insights and raising critical considerations for future research.
The published study by Squillacioti et al., titled “Different greenness exposure in Europe and respiratory outcomes in youths. A systematic review and meta-analysis,” delves into whether the benefits of greenery extend to the respiratory health of children and adolescents in European regions. The systematic review, registered under DOI 10.1016/j.envres.2024.118166, sheds light on the link—or the lack thereof—between exposure to greenness and the incidence of asthma in the younger population across Europe.
The authors undertook a comprehensive search of several databases, including PubMed/MEDLINE, EMBASE, Scopus, Web of Science, GreenFile, and CAB direct. The literature search, which sifted through records up until 29 August 2023, initially identified 4049 studies. After meticulous selection, 18 primary studies were included for systematic review, and six of these were considered for meta-analysis.
Contrary to what one might expect, the meta-analysis revealed no significant association between higher vegetation levels, as measured by the Normalized Difference Vegetation Index within 500-m buffers (NDVI-500), and a decrease in asthma odds for a 0.3 increase in exposure. Similarly, an overall exposure to the high tertile of NDVI-300, as compared to the low tertile, showed no statistically significant relationship with asthma prevalence in youths.
One notable finding was the significant heterogeneity among the included studies. Such diversity in methodology and outcomes indicates that the relationship between greenness and respiratory outcomes is a complex one, influenced by various factors, including geographical, environmental, and methodological differences.
The research team, led by Giulia Squillacioti from the Department of Public Health and Pediatrics at the University of Turin, suggests an urgent need for harmonized approaches to define greenness effectively. A nuanced understanding of how the interplay between green spaces and respiratory health varies across different European regions and climatic conditions is imperative.
The team calls for future studies to compare geographical areas with similar bioclimatic parameters, dominant vegetation species, and quantifiable elements of greenness. This comparative approach would enhance inter-study comparability and potentially unravel associations that have so far remained elusive.
Keywords
1. Green Spaces Health Europe
2. Youth Respiratory Outcomes
3. Urban Greenery Asthma
4. Environmental Research NDVI
5. Systematic Review Meta-Analysis
References
1. Squillacioti, G., Fasola, S., Ghelli, F., Colombi, N., Pandolfo, A., La Grutta, S., Viegi, G., & Bono, R. (2024). Different greenness exposure in Europe and respiratory outcomes in youths. A systematic review and meta-analysis. Environmental Research, 118166. doi: 10.1016/j.envres.2024.118166
2. Lovasi, G. S., Quinn, J. W., Neckerman, K. M., Perzanowski, M. S., & Rundle, A. (2008). Children living in areas with more street trees have lower prevalence of asthma. Journal of Epidemiology & Community Health, 62(7), 647-649. doi:10.1136/jech.2007.071894
3. Dadvand, P., de Nazelle, A., Figueras, F., Basagaña, X., Su, J., Amoly, E., … & Sunyer, J. (2012). Green space, health inequality and pregnancy. Environment International, 40, 110-115. doi:10.1016/j.envint.2011.07.003
4. Tischer, C., Gascon, M., Fernández-Somoano, A., Tardón, A., Lertxundi, A., Ibarluzea, J., … & Nieuwenhuijsen, M. J. (2017). Urban green spaces and childhood asthma: A longitudinal study in southern Europe. European Respiratory Journal, 49(6), 1601139. doi:10.1183/13993003.01139-2016
5. Markevych, I., Thiering, E., Fuertes, E., Sugiri, D., Berdel, D., Koletzko, S., … & Heinrich, J. (2014). A cross-sectional analysis of the effects of residential greenness on blood IgE levels in children: Results from the GINIplus and LISAplus studies. Allergy, 69(11), 1475-1483. doi:10.1111/all.12482
This comprehensive study by Squillacioti et al. represents a significant stride in environmental and pediatric health research. By meticulously analyzing the intricate tapestries of green spaces and respiratory outcomes, the study not only offers empirical evidence but also paves the way for future research directions. Importantly, it serves as a reminder that the natural environment’s contribution to our health is profound yet deeply complex, warranting ongoing inquiry and thoughtful examination.