Pollen exposure and paediatric Emergency Room admissions in Northern Italy (2008-2022)

We analysed the short-term association between tree pollen exposure and counts of paediatric Emergency Room (ER) admissions in the Veneto region, Northern Italy. For 2008-2022, we obtained daily pollen concentrations and ER admissions for natural causes among people aged 0-17 years residing within 10 km of 12 monitoring stations. We designed a case-crossover study stratified by area and day of the week/month/year. We estimated associations using nonlinear distributed lag quasi-Poisson regression, restricted to the March-October period and adjusted for holidays, temperature and precipitation. There were around 1 million paediatric ER admissions in the region during the study period. Across all areas combined, the 99^th percentile of daily concentrations ranged from 24 p/m³ for <italic>Alnus</italic> to 280 p/m³ for Corylaceae. We observed mainly immediate effects following pollen exposure, i.e. at lag 0 (Figure 1). <fig><object-id>erj;64/suppl_68/PA473/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> At lag 0, relative changes in ER admission counts (with 95%CI) for days with concentrations ≥1 p/m³, as compared to no pollen, were: <italic>Alnus</italic> +3.1% (+2.0,+4.2%); <italic>Betula</italic> -0.8% (−1.8,+0.2%); Corylaceae +1.0% (−0.1,+2.1%); Cupressaceae, +0.6% (−0.2,+5.3%); Oleaceae +4.3% (+3.4,+5.3%). Exposure to <italic>Alnus</italic> and Oleaceae pollen showed the strongest associations with increased paediatric ER admissions in the region during 2008-2022. Pollen forecasting alerts could aid susceptible individuals in implementing self-protection strategies.