Occupational exposures in sarcoidosis: a protocol for a multicentre regional case-control study in the UK.

backgroundSarcoidosis is a multisystem granulomatous disease of unclear cause. An environmental trigger in a genetically susceptible individual resulting in immune dysregulation is suspected. More than 90% of cases of sarcoidosis involve the lungs, suggesting that inhaled environmental antigens contribute to the onset of disease. Many potential environmental antigens have been proposed to date, although equipoise persists concerning occupational exposures.The SANDSTONE study (Silica and Sarcoidosis: a study of Occupational Exposures) is the first UK-based study that investigates the association between occupational exposures and a diagnosis of pulmonary sarcoidosis, with particular focus on respirable crystalline silica, metal dusts, inorganic dusts and organic dusts. METHODS AND ANALYSIS: The SANDSTONE study is a multicentre case-control study recruiting participants from across the West Midlands region of the UK. The study targets recruiting n=174 participants in each group (1:1 case: control study). Case participants are patients diagnosed with pulmonary sarcoidosis since 2010 while control participants are recruited from NHS secondary care outpatient clinics. All participants will complete a semistructured interview to obtain full lifetime occupational and environmental exposure histories, with limited retrospective clinical data collected. The primary outcome measure is the OR of silica, metal dusts and other prespecified occupational exposure in pulmonary sarcoidosis. ETHICS AND DISSEMINATION: The study is sponsored by University Hospitals Birmingham NHS Foundation Trust and has received ethical approval from the Cambridge East Research Ethics Committee (19/EE/0360).