PoCHAS - Effects of airborne pollen on cardiorespiratory health and allergic symptoms

Airborne pollen allergies are increasing across Europe, and are a major health issue for 20% of the Swiss population. At the same time, the duration and intensity of the pollen season are changing due to climate change. Pollen allergy is often dismissed as “not so serious”, though missed workdays, and millions spent on medication suggest otherwise. Affected people have gotten used to seasonal episodes of sneezing and teary eyes. Yet, it is not well recognized that high pollen concentrations may also have more severe and systemic impacts on our health.

The PoCHAS project aims to investigate how short-term exposure to pollen is related to respiratory and cardiovascular events. We will study mortality, hospitalization and self-reported allergic symptoms. Moreover, in light of increasing allergy prevalence, we aim to study how the relationship between pollen and health has developed over the study period, and which subpopulations might be most at risk. Moreover, combined exposure to pollen, air pollution and weather conditions could have synergistic effects, which alter the allergenicity of pollen - a research area that has been hardly explored.

We will use large, real-world datasets without selection bias: individual cause-specific mortality is available from the Swiss National Cohort (2003-2018) and hospital admissions from the hospital admission database of the Federal Office of Statistics. We will study the population effects of pollen on daily respiratory and cardiovascular mortality and hospitalization. We will investigate trends in how pollen affected each outcome over the last 16 years, as our climate and pollen exposure has been changing.

To explore individual sensitivity, we will use data from the Ally Science app (https://allyscience.ch/en/home/). Ally Science allows allergy sufferers to keep track of their day-to-day symptoms in an easy and straightforward way. Data collection has been ongoing in Switzerland since 2018 and will continue for the duration of the study. Security of personal data is an integral part of this project: Ally Science users contribute their data on a voluntary basis, and can determine freely if they want contribute their data to the project.

This project will help us better understand the role of pollen in self-reported symptoms, respiratory and cardiovascular diseases at the population level. This study will add substantially to the small body of scientific evidence regarding the sever health effects of airborne pollen. With these insights, we can prevent and reduce health effects due to pollen, which constitute a large burden on health and economy.

Glick S, Gehrig R, Eeftens M. Multi-decade changes in pollen season onset, duration, and intensity: a concern for public health?. Sci Total Environ. 2021;781:146382. DOI: 10.1016/j.scitotenv.2021.146382

Bürgler A, Glick S, Hartmann K, Eeftens M. Rationale and design of a panel study investigating six health effects of airborne pollen: the EPOCHAL study. Front Public Health. 2021;9:689248. DOI: 10.3389/fpubh.2021.689248

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