Model based ragweed pollen counts predict sleep difficulty in allergy immunotherapy patients in small clinic in Southeastern Michigan, USA

Abstract

Introduction: Allergic rhino-conjunctivitis impacts up to a quarter of the world’s population. Symptoms include sneezing, rhinorrhea, pruritus, and sleep disturbance. Ragweed (Ambrosia artemisiifolia) is a plant common to North America and an important allergen. Predicting allergic symptoms associated with ragweed has largely relied on crude and/or expensive methods of measuring airborne pollen counts. We apply a novel model-based raster of predicted pollen counts to test associations with self-reported symptoms of allergic rhino-conjunctivitis among patients receiving immunotherapy for pollen allergies at a University-based allergy clinic in the U.S. Methods: Patients receiving immunotherapy injections for seasonal allergies were enrolled in the study on site. Participants filled out a brief intake survey on allergic and symptomatic profiles, sleep quality, housing quality and demographics and then completed a daily sleep quality survey by email for 21 consecutive days. Using the date and GPS location of survey response, ragweed pollen counts were extracted from a model-based raster (25km pixels) of daily predicted pollen counts. Associations between predicted pollen counts and a composite index of sleep quality were estimated using ordinal logistic regression models. Results: 50 people were enrolled in the study; 26 (52%) were female. The mean age was 37.9 years. 96% of participants had lived in the area for more than a year. 28 (56%) of respondents were receiving immunotherapy for ragweed pollen. Pollen counts (in 1000s) the previous day was associated with severe sleeping problems (OR 1.83 (1.26, 2.66)), even when controlling for travel to other regions and age of respondent. Impacts on sleep quality were not limited to only persons known to have ragweed allergies. Conclusion: Model based predicted ragweed pollen counts can be used to forecast symptoms associated with allergic rhinitis in people with disease severe enough to receive immunotherapy.