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Background

Occupational silica exposure is a well-recognized cause of progressive, debilitating lung disease, including silicosis and silica-associated pulmonary fibrosis. Silica exposure has re-emerged as a major public health concern due to rapidly progressive disease among workers in industries such as countertop fabrication, mining, and construction. Many present with advanced disease and require lung transplants, with recent case clusters, particularly in younger, previously healthy adults. Workers who fabricate artificial stone (AS) countertops, in California primarily Latino immigrants who are often undocumented and lack access to medical care, have recently been identified as high risk for development of accelerated silicosis. Current literature describes the natural history of silicosis, yet little is known about early biomarkers of disease progression, molecular signatures associated with high-risk exposure, and predictors of clinical outcomes. Current data comes from retrospective chart reviews or limited cross-sectional sampling, which do not capture early changes in inflammatory pathways and the decline in lung function. The lack of comprehensive prospective datasets limits our ability to improve screening, develop precision-based diagnostics, and guide targeted interventions for at-risk workers.

Objective

This project addresses the documented gap by developing a prospective, longitudinal registry of over 100 engineered stone-exposed workers, integrating clinical data, patient-reported outcomes, and biospecimens (blood, nasal swabs, sputum) to evaluate biomarkers associated with silica exposure and disease progression. Through clinical and biologic data, the study will generate insights into risk factors, mechanistic pathways, and prognostic indicators of rapidly progressive silicosis. This will provide the foundation for future diagnostic tools, therapeutic strategies, and public health policies to reduce morbidity and mortality among workers exposed to silica.

Methods

This is a prospective, longitudinal, observational registry of adult workers (>18 years) exposed to engineered stone dust and is a collaboration between the University of California, Los Angeles (UCLA) Olive View Medical Center and the University of California, San Francisco (UCSF) Department of Medicine. Engineered stone-exposed workers with and without silicosis at varying stages will be identified and screened prior to their routine clinical appointments at the UCLA Olive View Pulmonary Clinic or the UCSF Occupational and Environmental Medicine Clinic, as well as through outreach to individuals with a known history of engineered stone exposure, including participants in the California Artificial Stone and Silicosis (CASS) Enhanced Medical Monitoring Study. Participants will undergo informed consent. Once enrolled, participants will complete a demographic survey. At baseline and at least every 12 months, participants will complete the occupational and symptom questionnaire, the King's Brief Interstitial Lung Disease (KBILD) questionnaire, the Modified Medical Research Council (mMRC) Dyspnea Scale, and the Patient-Reported Outcomes Measurement Information System (PROMIS 29 + 2). Clinical data will be captured via manual medical record abstraction, and no additional studies will be obtained outside of the standard-of-care. Clinical data will include pulmonary function testing, six-minute walk distance, computed tomography of the chest, pathology, laboratory data, microbiology, and echocardiogram and right heart catheterization data. All data will be input into a secure Redcap database. We will also collect blood samples and nasopharyngeal swabs for biobanking and use in identification of biomarkers with techniques such as RNA sequencing and proteomics. Data will be collected using standardized protocols to facilitate longitudinal analysis.

Results

Preliminary results include questionnaires from 26 participants enrolled between September 2025 and February 2026 at UCLA. All were Latino men from Mexico or Central America, with a median age of 51 years and varied immigration statuses. Participants reported worse-than-average outcomes in physical function, social participation, cognitive function, anxiety, depression, fatigue, sleep disturbance, and pain interference. At least half reported worrying about lung disease severity, anticipating worsening symptoms, and thinking about end of life. Over half (55%) had mMRC ≥2, indicating significant dyspnea. All reported some dry work without water. Only 35% had full-scope insurance. 23% used no respiratory protection, 31% used surgical masks, 8% were fit-tested, and 15% received training.

Conclusions

Despite ongoing efforts to reduce workplace exposure to respirable silica, we expect to continue to see a rise in patients with silicosis. A clearer understanding of the disease mechanism will aid in the development of targeted therapies to slow down, or completely stop, disease progression. The registry will enable characterization of disease trajectories, symptom burden, and functional decline over time, and will support hypothesis generation for future clinical and translational studies of this emerging occupational lung disease.