Residing near allergenic trees can increase risk of allergies later in
life: LISA Leipzig study
Background: We investigated whether residing in places with higher
greenness, more trees and more allergenic trees early in life increases
the risk of allergic outcomes, and whether these associations differ
depending on the concentration of air pollutants. Methods: The analytic
sample included 631 children from the German birth cohort LISA Leipzig.
Asthma and allergic rhinitis, sensitization to aeroallergens and food
allergens, as well as confounders, were collected prospectively up to 15
years. Greenness was assessed by Normalized Difference Vegetation Index
(NDVI). A tree registry was used to derive information on trees, which
were classified into allergenic and non-allergenic. Annual average
concentrations of nitrogen dioxide (NO2) and ozone were also used.
Geographic exposures were assigned to home addresses at birth.
Longitudinal associations were analysed using generalized estimating
equations. Results: Medium and high numbers (tertiles) of trees and
allergenic trees in a 500 m buffer around birth addresses were
associated with increased odds of allergic rhinitis up to 15 years
regardless of NDVI. These exposures were also related to higher odds of
sensitization to aeroallergens. Associations with asthma and
sensitization to food allergens were less consistent. Effect estimates
for allergic rhinitis were stronger in the high tertile of NO2 compared
to the low tertile, while an opposite tendency was observed for ozone.
Conclusion: We observed that early life residence in places with many
trees, and allergenic trees specifically, may increase the prevalence of
allergic rhinitis later in life. This association and its modification
by air pollution should be pursued in further studies.