Pollen has been identified as a risk factor for allergic and non-allergic respiratory symptoms in older age groups. However, there is no study on the impact of pollen for the first year of life, a particularly vulnerable period for lung development. A better understanding of the effects of pollen on the respiratory system in infancy may help improve respiratory health in the short and long term.

Amanda Gisler and colleagues wanted to assess whether exposure to grass and tree pollen in the first year of life is associated with an increased risk of respiratory symptoms (cough, wheezing, respiratory symptoms). In addition, they tried to evaluate whether a maternal predisposition to allergic reactions, male sex, or air pollution increased the susceptibility to pollen. For this the scientists used the data (ca.14.800 observations) from 401 infants from the Basel Bern Infant Lung Development (BILD) cohort. In the analysis period (January through September) they recorded weekly the symptoms of the children in telephone interviews. The pollen exposure for the corresponding week was estimated for each infant using data from the nearest monitoring station. Advanced statistical models were applied to examine whether there was a significant association between individual pollen exposure and respiratory symptoms and whether other factors, such as air pollution, exacerbated the effects of pollen.

In this longitudinal study Amanda Gisler and her team could show that exposure to tree and grass pollen is associated with an increased risk of respiratory symptoms already in the first year of life. They found this association even in healthy term-born infants. An allergic reaction or pollen-induced suppression of the immune response could be possible mechanisms linking pollen exposure and respiratory symptoms. Furthermore, they found that the effect of pollen did not depend on maternal predisposition to allergic reactions or the infant's sex. However, they found a complex interaction effect of pollen and air pollution on respiratory symptoms. 

This study shows that exposure to grass and tree pollen increases the risk of respiratory symptoms even as early as during the first year of life. This finding is significant because virtually every child is exposed to pollen and infancy is a particularly sensitive period for lung development. The better understanding of the effects of pollen during this sensitive period may serve as a starting point for future studies to elucidate the association between pollen and respiratory symptoms.

Pollen exposure is associated with risk of respiratory symptoms during the first year of life. Amanda Gisler, Marloes Eeftens, Kees de Hoogh, Danielle Vienneau, Yasmin Salem, Sophie Yammine, Julian Jakob, Olga Gorlanova, Fabienne Decrue, Regula Gehrig, Urs Frey, Philipp Latzin, Oliver Fuchs, Jakob Usemann, BILD study group. Allergy. 2022;00:1–11.