Background: Silicosis is one of the most common forms of pneumoconiosis worldwide. In Rwanda - there is paucity of data on the silicosis burden and occupational risk among underground miners. Methods: We conducted a cross-sectional study among all miners from 8 cassiterite (tin ore) mining sites in Kayonza district, Eastern Rwanda. Questionnaire data and chest radiography were collected at Rwinkwavu District Hospital. Two radiologists reviewed all the chest radiography using ILO criteria, with a third radiologist reviewing films with ILO rating discrepancies and serving as an arbiter. Logistic regression was performed to investigate risk factors associated with radiographic silicosis. Findings: In total, 1,021 mine workers were included in the primary outcome (risk) analysis. The median age was 32 years (IQR 26-40), and 948 participants (93%) were male. Of all participants, 94 (9%) were diagnosed with silicosis. Increased odds of silicosis were associated with working in a blasting station (aOR 3∙30; 95% CI 1∙68-6∙45), excavation station (aOR 2∙77; 95% CI 1∙09-7∙04), drilling station (aOR 2∙51; 95% CI 1∙34-4∙70), exposure to tobacco (aOR 1∙92; 95% CI 1∙14-3∙24), and increased time of working in mining (aOR 1∙05; 95% CI 1∙01-1∙09). Interpretation: Almost 1 in 10 Cassiterite miners in an occupational cohort of active and retired miners in the Eastern Province of Rwanda were found to have Silicosis. Tobacco use, certain mining tasks and duration of mining employment were significantly associated with increased risk of having a silicosis diagnosis. Our results indicate that screening and preliminary occupational risk analysis in a rural mining cohort is technically feasible. Funding: All funding was provided by internal grants through the Non-Communicable Diseases program through Partners in Health/Inshuti Mu Buzima

Paul Sonenthal has received grant support from Unitaid, CHEST, the Wyss Foundation, the World Bank, the WHO and CHAI for expanding the provision of oxygen in low- and middle-income countries and expanding critical care resources in developing countries. He also has received consulting fees from UCSF/Sustainable Technical and Analytics Resources for review of USAID oxygen investments, and reports investment in minimally invasive mitral valve prosthesis through Nininger Medical. The rest of the authors have no competing interests to report

https://clinicaltrials.gov/study/NCT05538299

This research received no specific grant from an NGO, not-for profit, private, commercial or federal funding source. It was funded internally under the Non-Communicable Diseases budget of Partners In Health-Rwanda otherwise known as Inshuti Mu Buzima.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Inshuti Mu Buzima Research Committee (IMBRC) and the Rwandan National Ethics Committee (RNEC) 110/RNEC/2022 gave ethical approval of this work.

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The authors acknowledge that data collected for this study, including participant data can be made available to others per Rwandan law. Data that is made available will be deidentified and includes questionnaire data, radiography data and other demographic data. Study protocol can be viewed on clinicaltrials.gov at NCT05538299. Informed consent form can be provided on request. Per Rwandan patient confidentiality law, patient data cannot be made publicly available. For parties interested in obtaining study data, they will need to submit a data sharing/access agreement to Inshuti Mu Buzima which will need to be approved by the Rwandan Data Security Office. Data can be made available by request after the publication date. Additionally, study tools and questionnaire used for this paper available without translation by request. Requests can be initiated by communication with the corresponding author (samuel.hatfield@ucsf.edu)