Association of Allergic Sensitivity and Pollination in Allergic Respiratory Disease: The Role of Pollution

To evaluate the association between allergic sensitivity and pollen counts in patients with allergic respiratory disease (ARD) and its relationship with atmospheric pollutants.

From 2012 to 2018, we evaluated the sensitivity by skin prick test in ARD patients. The pollen counts were analyzed according to international guidelines (2014-2018). The pollutant and meteorological data were obtained at the same time from AIRE-CDMX websites. We analyzed the association between allergic sensitivity and pollen counts using the χ2 test and stratified by disease allergic rhinitis (AR) and AR with asthma (ARwA), periods (before/after 2015), and pollination seasons (S1:2014-2015), (S2:2015-2016), (S3:2016-2017), (S4:2017-2018). Likewise, we correlated the pollen counts with the concentrations of pollutants using Pearson's correlation. For all analyses, we used SPSS v.21 software, and a p-value <0.05 was considered significant.

A total of 520 patients were enrolled, of whom 67.3% had ARwA and 33.7% had AR (p<0.05). The frequency of patients allergic to at least one pollen was higher compared with patients sensitive to indoor allergens (55.3% vs 44.6%, p<0.001). A total of 46.8% of the patients were only sensitive to trees in comparison to other outdoor allergens (p<0.001). The Fraxinus sp. and the Cupressaceae family allergens were approximately two times more frequent than the other tree allergens in both diseases (p<0.05). These pollens doubled their counts since 2015 (p<0.001), which was associated with increases in sensitivity for Fraxinus sp. and the Cupressaceae family compared to previous years (p<0.001). Regarding pollutants, the most significant correlations were with PM₁₀, NO₂, PM_CO for Fraxinus sp. pollen concentrations in all seasons (p≤0.02).

The high increases in pollen counts of the Fraxinus sp. and Cupressaceae family were associated with increases in the frequency of sensitization to these species, and this phenomenon correlated with increases in PM₁₀, NO₂, and PM_CO.