More than a sneeze: Effects of daily airborne pollen exposure on blood pressure in adults (EPOCHAL study)

BACKGROUND AND AIM The dose-response relationship between pollen exposure and acute systemic health effects, such as elevated blood pressure (BP), has been inadequately studied. The EPOCHAL cohort study (Effects of Pollen on Cardiorespiratory Health and ALlergies) aims to investigate the association between pollen exposure and six different health outcomes, including BP. METHODS We collected seated systolic and diastolic BP (BPsys, BPdia) in 102 allergic and non-allergic adults repeatedly (minimum 14 days) over six weeks during their typical symptomatic period. A skin prick test was performed to confirm pollen sensitization. We applied mixed effects models to regress daily BPsys and BPdia on daily pollen concentration of two highly allergenic species (birch, grasses) as well as the total of twelve species. Daily pollen concentration (grains per m3) was log-transformed prior to analysis. We adjusted for age, sex, BMI, food consumption, medication use and exercise before the test, time of day, and daily air pollution (NO2, PM2.5) and temperature. RESULTS Total pollen concentration was associated with a significant increase of 0.54 mmHg in BPsys per increment of 1 log[Pollen]. The same increment for grass pollen was significantly associated with 0.39 mmHg higher BPsys as well as 0.28 mmHg higher BPdia. In a subgroup analysis of participants with self-reported symptoms and positive skin prick test (N=68), we found significant associations between total pollen concentration and elevated BPsys (0.69 mmHg) and BPdia (0.43 mmHg) as well as between birch pollen concentration and BPsys (0.79 mmHg) and BPdia (0.62 mmHg). CONCLUSIONS We found increased BPsys and BPdia related to higher same-day pollen exposure. Effect sizes increased if we restricted the analysis to objectively confirmed pollen allergy sufferers. After completion of data collection (N=400) in 2022, we will investigate lagged pollen exposure and splines to further describe pollen-BP dose-response relationships. KEYWORDS Air pollution, Pollen Allergy, Cardiovascular diseases