Associations between ambient pollen exposure and measures of cognitive performance

Prior research suggests pollen allergies may be associated with cognitive function, although the effect sizes and specific cognitive outcomes varied across studies. With pollen seasons starting earlier and intensifying due to climate change, understanding the effects of pollen exposure on cognition is increasingly relevant. This study investigated the relationship between ambient pollen exposure and cognitive performance in Swiss adults.

Four cognitive assessments were used to measure the daily performance of 392 participants (299 with pollen allergies) over a 10-day period during pollen season. We used generalized additive mixed models to assess the exposure-response relationship between individualized pollen exposure and cognitive performance, as well as allergic symptom severity and cognitive performance, adjusting for individual characteristics and time-varying environmental and individual confounders (e.g., air pollution, weather, and coffee intake).

We did not find any statistically significant relationships between pollen exposure or severity of allergic symptoms and overall score or reaction time on tests of response inhibition, attention, and visual-spatial memory. We observed a 1% increase [95% confidence interval (CI) = 0.13%, 2.0%] in average reaction time on a test of grammatical reasoning for allergic participants at an exposure of 300 pollen/m³ (12-hour average).

Overall, our study population did not exhibit changes in cognitive performance related to pollen exposure or perceived allergic symptoms. A marginal, but statistically significant effect on the response time of pollen-allergic individuals was observed for a test of verbal reasoning, however, this is likely to be a chance finding considering the number of exposures and outcomes evaluated.