Background/Aim: Grass (Poaceae) pollen is the most significant outdoor aeroallergen, and is linked to asthma exacerbations and respiratory allergic response.

Understanding of the relative contributions of different grass taxa to respiratory health outcomes is currently unknown. We investigate associations between a range of grass genera and proxies of both asthma exacerbation (hospital admissions) and respiratory allergic response (prescribing rates). A better understanding of allergenic exposures will allow better disease management by patients and healthcare providers. This work forms part of the PollerGEN Project.

Methods: Combining metagenomics and pollen count data, we produced semi-quantitative estimates of concentrations of the pollen of 14 grass genera and undifferentiated (i.e. unidentified) Poaceae, at six sites across the UK during the pollen season (May to September) of 2016. Using a series of generalised additive models (GAMs), these data are being combined with hospital admissions and prescribing datasets (and various confounding datasets) to assess associations between different types of grass pollen with serious asthma exacerbations and respiratory allergic response at a population level.

Results: Preliminary GAMs, adjusted for weather, air pollution, rural-urban status, deprivation, health organisation and time period, explain >95% of variation in health outcome variables (adjusted R2 = 0.912). Notably, they suggest a potential positive relationship between respiratory antihistamines and concentrations of Holcus pollen during the 2016 UK pollen season (F = 25.9, P = 2.41 x 10^-8), whereas overall grass pollen concentrations (i.e. standard pollen ‘counts’), did not provide significant correlation.

Conclusions: Our preliminary results suggest that certain grass taxa may contribute more than others to respiratory health outcomes in the UK, including contributing more than overall grass pollen concentrations. This may be due to pollen grains of certain grass taxa containing proteins which are more allergenic or greater concentrations of allergenic proteins, greater sensitisation, or greater levels of exposure to these taxa.