Newcastle United Foundation

Abstract Rationale: Hypersensitivity pneumonitis (HP), a common interstitial lung disease (ILD), presents in two distinct but related forms, acute and fibrotic (fHP). HP is classically described as a disease triggered by inhaled exposure to a proven or likely causative antigen. However, a wide range of inhaled triggers are described and in ∼50% of cases no clear trigger is identified, rendering observational studies challenging. The British Pigeon Fanciers Genetics of ILD (BPF-GILD) study aims to address this by creating an observational cohort with longitudinal data and linked electronic healthcare records of individuals who have been exposed to the same antigens. Methods: Participants were recruited from 2019 to 2024 at large UK Pigeon Fancier meetings. Informed written consent was obtained from participants, including for linkage to electronic health care records. Each participant performed spirometry, completed a standardised questionnaire with an experienced doctor, and provided blood samples for antigen tests and generation of omics data (such as genetics and proteomics). Individuals who returned to subsequent meetings repeated questionnaires, blood samples and spirometry. Results: 465 subjects were recruited from five meetings, with 79 individuals returning for at least one repeat measurement and 11 individuals completing four visits. The median age at baseline of the cohort was 63 years, 95% were male and 94% self-reported white ethnicity. Cohort members kept a median number of 80 pigeons (range 4-800), had kept pigeons for a median of 39 years (range 1-79) and participants spent a median of 14 hours per week (range 1-100) in their lofts. 14% of the cohort had suspected ILD diagnosis at baseline with five additional individuals present with a suspected ILD at later visits. Individuals were more likely to wear a mask when with their birds if they had suspected ILD. Measures of FEV1 (forced expiratory volume in first second), FVC (forced vital capacity) and the proportion of individuals wearing masks remained similar across visits. Conclusion: Our well characterised pigeon fanciers commonly experience acute HP symptoms and are likely to be at increased risk of fHP. Subsequent work using stored samples and utilising electronic healthcare records over time will enable us to determine genetic risk factors and pathways relevant to the development and progression of fHP.