Impact of asthma in Europe: A comparison of web search data in 21 European countries

Abstract

Background: Asthma is a chronic inflammatory disorder of the airways and one of the most important non-communicable diseases worldwide. Analyzing crowdsourced data can help understand public interest and unmet needs as well as potential factors influencing search behavior.

Objective: The study aimed to investigate asthma-related web search data in Europe to identify possible regional and seasonal variations and to assess public interest.

Methods: Google Ads Keyword Planner was used to measure search volume for search terms related to asthma, allergic asthma, and bronchial asthma in 21 European countries between January 2018 and December 2021. The top 10 keywords of each country were categorized qualitatively. Search volume per 100 000 inhabitants was descriptively assessed in terms of regional and seasonal trends. Spearman correlations between search volume and pollen concentration as well as coronavirus disease (COVID-19) cases were investigated.

Results: The median search volume per 100 000 inhabitants for asthma and allergic asthma was highest in Northern and Western Europe, while the highest search volume for bronchial asthma was observed in Western and Eastern regions. A seasonal trend was identified for all search terms and in all regions. Correlations were found between search frequency and pollen load and search behavior and COVID-19 cases. Overall, Europeans were most interested in the diseases in general, their treatment options, and symptoms.

Conclusion: These results highlighted the need for reliable and region-specific information about the disease and for public campaigns to improve asthma control. The study also emphasizes the importance of using crowdsourced data for a more encompassing overview beyond conventional healthcare data.

Keywords: Asthma; COVID-19; Infodemiology; Pollen; Web search.

Fig. 1

Median web search volume between 2018 and 2021 for each European country examined, with separate maps for the search terms asthma, allergic asthma, and bronchial asthma. Malta was displayed as an enlarged dot for better illustration.

Fig. 2

Time course of the normalized median web search volume per 100 000 inhabitants for search terms asthma, allergic asthma, and bronchial asthma between 2018 and 2021 (solid lines) separately for the 5 European regions and normalized pollen concentration of birch (dashed line) and grass (dotted line) from a Munich measuring station. European regions were defined geographically as Northern (Denmark, Ireland, Sweden, and United Kingdom), Eastern (Czech, Hungary, Poland, Romania, and Ukraine), Western (Austria, France, Germany, and the Netherlands), Southern (Italy, Malta, Portugal, and Spain), and Southeastern Europe (Bosnia, Croatia, Greece, and Serbia).

Fig. 3

Time course of the normalized median web search volume per 100 000 inhabitants for search terms asthma, allergic asthma, and bronchial asthma between 2018 and 2021 (solid lines) and the normalized median number of COVID-19 cases between 2020 and 2021 (dashed lines) separately for the 5 European regions: Northern (Denmark, Ireland, Sweden, and United Kingdom), Eastern (Czech, Hungary, Poland, Romania, and Ukraine), Western (Austria, France, Germany, and the Netherlands), Southern (Italy, Malta, Portugal, and Spain), and Southeastern Europe (Bosnia, Croatia, Greece, and Serbia).

Fig. 4

Mosaic plot for the search terms asthma, allergic asthma, and bronchial asthma for each European region based on the ten most frequent keywords of the corresponding search term. For each country, the top 10 keywords were considered if 10 were available, otherwise fewer keywords were used. European regions were defined geographically as Northern (Denmark, Ireland, Sweden, and United Kingdom), Eastern (Czech, Hungary, Poland, Romania, and Ukraine), Western (Austria, France, Germany, and the Netherlands), Southern (Italy, Malta, Portugal, and Spain), and Southeastern Europe (Bosnia, Croatia, Greece, and Serbia).