Methods
We ran a MEDLINE literature search of observational studies conducted in humans and published in one of the three European Academy of Allergy and Clinical Immunology (EAACI) journals, Allergy , Clinical and Translational Allergy (CTA ), and Pediatric Allergy and Immunology (PAI ), between 2009 (2011 for CTA , its foundation year) and 2018. The literature search was conducted using the search string ((”pediatr allergy immunol”[TA] OR ”clin transl allergy”[TA] OR ”allergy”[TA]) AND 2009:2018 [DP] NOT (”Editorial”[PT] OR ”Letter”[PT] OR ”Review”[PT] OR ”Clinical Trial”[PT] OR ”Case Reports”[PT])).
The search string generated overall 2,707 records with a median of 328 papers identified per year, ranging between 263 papers published in 2014 to 392 papers published in 2009. We randomized within journal and year. Only observational studies in humans to which STROBE would apply were eligible. So, we retained the first 8 eligible papers on that randomly ordered list. In case the full-text revealed that this was not an observational study, we excluded the paper and replaced it with the next paper on the random list. In the end, PAI contributed 80 records (8 per each of the 10 years; 35.9%), Allergy contributed 80 records (35.9%) and Clinical and Translational Allergy(CTA ) contributed 63 records (28.2%) because it was only founded in 2011 with and had published only 9 suitable observational studies in its inaugural year.