BPF-GILD study: an observational cohort study of UK pigeon fanciers

Introduction Hypersensitivity pneumonitis (HP), a common interstitial lung disease (ILD), comprises two distinct but related forms, acute and fibrotic (fHP). HP is classically described as a disease triggered by antigen exposure. However, a wide range of triggers are described and in ~50% of cases no cause is identified, rendering observational studies challenging. The British Pigeon Fanciers Genetics of ILD (BPF-GILD) study aims to address this by studying a population with a clear history of exposure to a common trigger. Methods Participants were recruited from 2019 to 2023 at large UK Pigeon Fancier meetings. Each participant performed spirometry, completed a standardised questionnaire with a doctor, and provided blood samples. We present our baseline data in this manuscript. Results 417 subjects were recruited from four shows. The median age of the cohort was 63 years, 95% were male and 94% self-reported white ethnicity. The median number of pigeons kept was 80 [range 4-800], with fanciers spending 14 hours per week [1-100] in their lofts. 52% of participants had occupational dust exposures. 49% of the cohort reported at least one respiratory symptom related to loft exposure. 14% had a history of ILD and these individuals had more loft-related respiratory symptoms, poorer lung function, and appeared more likely to wear a mask with their pigeons than those without (74% vs 57%). 41% of participants had positive responses to questions employed to detect occult connective tissue disease in ILD clinics. Discussion Our well characterised cohort of pigeon fanciers commonly experience acute HP symptoms and are likely to be at increased risk of fHP. Subsequent work using stored samples will enable us to determine genetic risk factors and pathways relevant to the development of fHP.