The green environment can provide buffers against air pollution and extreme temperatures, as well as opportunities for exercise. But it may be a source of allergens. Cross-sectional studies have found mixed associations between the green environment and lung function.
We estimated the associations between markers of green environment and repeated lung function measurements in 3 European birth cohorts, including 1880 participants from PIAMA (Netherlands), 1473 from GINI/LISA-North (Germany) and 1632 from GINI/LISA-South (Germany).
Spirometry was taken at ages 8, 12 & 16 (PIAMA) and 6, 10 & 15 (GINI/LISA). The Normalized Difference Vegetation Index (NDVI) in a 500m buffer was used to characterize residential greenness. The presence of urban green spaces in a 300m buffer was also considered. Linear mixed models estimated the associations between these green exposure metrics and FEV1 and FVC, adjusted for age, sex, height, weight, socioeconomic status and smoking. Cohort-specific results were combined using a random-effects meta-analysis.
An increase in 0.2 units of NDVI predicted an increase of 0.04L (95%CI= -0.02, 0.10) in FEV1 and 0.05L (95%CI= -0.00, 0.11) in FVC. The presence of urban green spaces predicted an increase of 0.07L (95%CI= -0.08, 0.22) in FEV1 and 0.06L (95%CI= -0.08, 0.20) in FVC. Heterogeneity between studies was high (I2 > 89%). Markers of residential green environment were weakly associated with repeated measures of FEV1 or FVC. The high heterogeneity may be due to differences in vegetation and other environmental factors (i.e., pollution) across cohorts. Analysis of other CADSET cohorts is ongoing and will strengthen results.