Influence of climate change on prevalence of pollen sensitization in northern Taiwan

Pollen sensitization is not as common as mite sensitization in Taiwan. The dearth of regional aeropalynological studies and relevant clinical analyses has, therefore, led to an underestimation of the prevalence of pollen allergies. To investigate this impact, we evaluated the alteration of pollen sensitization and its association with climate change in northern Taiwan.

We enrolled the patients from National Taiwan University Hospital who lived in Taipei and New Taipei City, tested positive for pollen-specific immunoglobulin E (IgE) on an OPTIGEN® allergen-specific IgE assay, and had relevant symptoms. Their data were cross-referenced with climate data from the Central Weather Bureau for the same period.

In total, 11,895 patients were enrolled, of whom 930 (7.8 %) tested positive for pollen-specific IgE. Black willow was the most common pollen allergen identified. According to the Cochran-Armitage test, the annual sensitization to Bermuda grass, Japanese cedar, pigweed, ragweed mix, and black willow pollen varied significantly. According to Spearman's correlation test, the annual sensitization to Bermuda grass, white mulberry, ragweed mix, timothy grass, and black willow positively correlated with the mean winter temperature, whereas that to white mulberry and timothy grass negatively correlated with mean winter rainfall.

The pollen sensitization pattern has changed gradually in northern Taiwan over recent years. Warm mean temperatures and low mean rainfall in winter significantly correlated with annual sensitization to some pollen allergens. Climate change may have exacerbated the prevalence of pollen sensitization, and the emerging burden of pollen allergies should not be neglected in Taiwan.