Cohort profile: ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden).

The ESPRESSO study constitutes a novel approach to examine the etiology and prognosis of gastrointestinal disease in which histopathology plays a prominent role. Between 2015 and 2017, all pathology departments (n=28) in Sweden were contacted and asked to procure histopathology record data from the gastrointestinal tract (pharynx to anus), liver, gallbladder, and pancreas. For each individual, local histopathology IT personnel retrieved data on personal identity number, date of histopathology, topography (where the biopsy is taken), morphology (biopsy appearance), and where available free text. In total, between 1965 and 2017, histopathology record data were available in 2.1 million unique individuals, but the number of data entries was 6.1 million because more than one biopsy was performed in many of the study participants. Index individuals with histopathology data were matched with up to five controls from the general population. We also identified all first-degree relatives (parents, children, full siblings), and the index individual's first spouse. The total study population consisted of 13.0 million individuals. Data from all the study participants have been linked to Swedish National Healthcare Registers allowing research not only on such aspects as fetal and perinatal conditions and the risk of future gastrointestinal disease but also on the risk of comorbidity and complications (including cancer and death). Furthermore, the ESPRESSO database allows researchers and practitioners to identify diagnoses and disease phenotypes not currently indexed in national registers (including disease precursors). The ESPRESSO database increases the sensitivity and specificity of already-recorded diseases in the national health registers. This paper is an overview of the ESPRESSO database.