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.