Search term “colonoscopy” was translated with Google Translate services to official languages of the EU. Those terms were queried in the Google search engine. Language of each result from generated list was assessed with Google Translate. Results in other languages than searched term were excluded. The first 50 search results in the searched term language were recorded. Previous studies demonstrated that internet users do not read beyond the 50 hits [14]. Online forums, advertisements, personal blogs, videos, and scientific articles were excluded. A website was classified as an advertisement if primarily contained promotional material for a specific drug, clinician, and medical center and/or did not have a focus on patient education [1]. Online electronic materials dedicated to other procedures (i.e., colposcopy, gastroscopy, sigmoidoscopy), natural remedies, other cancers (i.e., cervical cancer), vaccinations (i.e., COVID-19), prevention services, and personalized colorectal centers also were excluded. Included websites were written in searched term language, were not password protected, were free to the public, and had focus on patient education. The EU has 24 official languages: Bulgarian, Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hungarian, Irish, Italian, Latvian, Lithuanian, Maltese, Polish, Portuguese, Romanian, Slovak, Slovenian, Spanish, and Swedish [15]. In this study, Maltese and Irish were excluded due to very low search yield (64 and 95 hits, respectively) and negligible prevalence (0 and 2 included websites, respectively).

Included articles were evaluated with Lix formula, a validated readability measure [16]. Unlike other measures (i.e., the Gunning Fogg Index), Lix was proved to be reliable readability measure across several languages (Swedish, Danish, English, French, German, Finnish, Italian, Spanish, Portuguese) [17]. It is considered by scientific community to be a reliable readability measure for all European languages [16, 17]. Apart from being easy to calculate and interpret, it bypasses issues with syllabification, which makes it suitable for even such complex languages like Chinese and Arabic [16]. Website text was copied into the Microsoft Word and all extraneous text (i.e., hyperlinks, affiliations, figures, legends, adverts, disclaimers, author information, copyright notices, and author information) was removed. Save as Plain Text function was utilized. Then, relevant language of the analyzed website was selected. Spelling & Grammar was checked and corrected by Microsoft Word. Then, text was copied to https://haubergs.com/rix online Lix calculator. Lix score, number of sentences, number of words, and average number of words in one sentence were recorded. When interpreting Lix scores, scale proposed by Anderson was applied [17]. Text with score < 20 was classified as very easy to comprehend, < 30 easy, < 40 little hard, < 50 hard, and < 60 very hard to comprehend [17].

Mean LiX scores, number of sentences, and number of words were compared across all analyzed languages using analysis of variance (ANOVA). To examine correlation between number of hits and mean Lix score of analyzed articles, univariate linear regression was utilized. P value equal or less than 0.05 was considered statistically significant. Analyses were conducted using JASP version 0.17.1 (JASP Team, University of Amsterdam). In this study, Microsoft Word version 16.59 (Redmont, USA) was utilized.