8279516 Autoimmune disease and prevalence of autoantibodies amongst workers exposed to high-dose respirable crystalline silica

<h3>Objectives</h3> Occupational exposure to silica has been long associated with a risk of autoimmune diseases including rheumatoid arthritis and systemic sclerosis. A modern epidemic of silicosis is emerging internationally, associated with dry processing of engineered stone with high (&gt;90%) RCS content. We researched the prevalence of clinical autoimmune disease and common autoantibodies in exposed workers. <h3>Material and Methods</h3> As part of a free screening programme, current and former stone benchtop industry workers in Victoria, Australia were asked questions and had blood taken for rheumatoid factor (RF), anti-nuclear antibodies (ANAs), and extractable nuclear antigens (ENAs). <h3>Results</h3> In total,1238 workers (93.3% male) were screened between 2019 and 2021, in whom 0.9% had diagnosed autoimmune disease. Among those without clinical disease, 24.6% had positive ANAs (93.5% male), 4.6% ENAs and 2.6% were RF positive. Positive autoantibodies were associated with age; smoking; exposure to RCS and silicosis diagnosis. <h3>Conclusion</h3> The proportion of workers with detectable ANAs or ENAs was considerably higher than the 5-9% expected in the general population. Some positive antibodies (e.g., Scl-70, CENPB), are of high sensitivity and specificity for systemic sclerosis. Long-term follow-up will be needed to estimate incidence. Screening for autoimmune disease is indicated in workers exposed to RCS as these individuals need specialised management and may be entitled to compensation.