Discussion
This is the first population-based cohort study to assess longitudinally
the effects of exposure to green spaces on the development of allergic
rhinitis up to 27 years of age. Unlike previous studies, we applied
individual-level exposure based on information on prenatal and life-time
residential addresses. Our results based on a strong study design
provide novel evidence that early-life cumulative exposure to green
spaces, measured as mean NDVI, during the spring increases the risk of
developing allergic rhinitis up to young adulthood, whereas green space
exposure in the summer decreases this risk. In addition, the results
suggest that air pollution levels may modify the associations between
green space and allergic rhinitis, so that the beneficial effects of
green space are stronger at high levels of air pollution.