Abstract Rationale Silicosis is a pneumoconiosis caused by deposition of silica in the lung and can be associated with fibrosis. Despite a significant burden among miners in low- and middle-income countries, there is limited data on lung function trajectory and risk factors for deterioration in these settings. We used longitudinal data for a cohort of cassiterite miners with silicosis in Kayonza District, Rwanda, to characterize changes in FEV1 and FVC and analyzed subgroups based on the presence of fibrosis. Methods We conducted a retrospective cohort study of miners with radiographically confirmed silicosis completing baseline and 8-month follow-up spirometry between November 2022 and July 2023 at Rwinkwavu District Hospital. Presence of fibrosis was a binary variable determined from baseline chest radiographs using a profusion score cut-off of 1/1. Primary outcomes were absolute difference in FEV1 and FVC from baseline to follow-up. Continuous variables were reported as medians (interquartile ranges). We used Wilcoxon rank sum tests to compare baseline characteristics between fibrosis subgroups and used multivariate regression to obtain age-adjusted outcomes. Results 63 participants were included, 9 (14.3%) of whom had fibrosis. Median age was 41 (36 to 49) years, median mining duration was 13.5 (10 to 18) years, and median BMI was 20 (19 to 21) kg/m2. These were not statistically different among participants with and without fibrosis. Baseline FEV1 among participants with fibrosis was 1,930mL (1,690 to 2,280) compared to 2,840mL (2,500 to 3,160) in those without (p = 0.029), and baseline FVC among participants with fibrosis was 3,100mL (2,810 to 4,290) compared to 3,535mL (3,160 to 4,000) in those without (p = 0.157). Among participants with fibrosis, the median 8-month change in FEV1 was -170mL (-280 to 160) compared to -85mL (-190 to 40) in those without and the 8-month change in FVC was -350mL (-520 to 150) compared to -30mL (-80 to 280) in those without. In multivariate regression adjusting for age, fibrosis was associated with an 8-month change in FVC of -447mL (95% CI -806 to -89) and FEV1 of -125mL (-313 to 63). Conclusion Miners in Kayonza District, Rwanda with fibrotic silicosis had significantly greater absolute decline in FVC over the 8-month study period adjusting for age compared to those with non-fibrotic disease, suggesting fibrosis may be a predictor of more rapid progression of lung injury in this population. Larger studies are needed to further define risk factors and guide prevention and management strategies in mining populations in Rwanda and globally. This abstract is funded by: CHEST
Surya et al. (2026) studied this question.