Silicosis and silicotuberculosis among respiratory hospital admissions: A cross-sectional survey in northern Tanzania

BACKGROUND: There is little evidence describing respiratory disease among 40.5 million small-scale miners worldwide. OBJECTIVES: To describe the prevalence and clinical characteristics of adult respiratory inpatients with silicosis and silicotuberculosis in a tertiary hospital in Tanzania that serves a small-scale mining region. METHODS: In this retrospective, cross-sectional survey, patient files from admissions between 2010 and 2020 were opportunistically selected and included if a respiratory diagnosis had been made. RESULTS: Of 223 patients with respiratory conditions, 32 (14.3%; 95% confidence interval (CI) 10.0 - 19.6) were diagnosed with silicosis and 17 (7.6%; 95% CI 4.5 - 11.9) with silicotuberculosis. Mining was the most frequent occupation in those with silicosis (n=15/32; 46.9%) and silicotuberculosis (n=15/17; 88.2%). Of those with silicosis or silicotuberculosis, 26/49 (53.1%) were aged <45 years. CONCLUSION: Our study suggests that silicosis and silicotuberculosis are common among male and female respiratory inpatients with occupational exposure. The study highlights the role of occupational exposures in respiratory disease in developing economies. STUDY SYNOPSIS: What the study adds. This retrospective, cross-sectional survey describes the prevalence of silicosis and silicotuberculosis among adult respiratory inpatients admitted to a tertiary hospital in northern Tanzania. It is the first study to describe the prevalence and characteristics of respiratory inpatients with silicosis and silicotuberculosis in a small-scale mining region of Africa. A high prevalence of silicosis (14.3%) and silicotuberculosis (7.6%) was found. Patients were often aged <45 years, and the majority required oxygen therapy. Implications of the findings. The high prevalence of advanced silicosis and silicotuberculosis in miners presenting at a young age raises concerns about high occupational silica exposures and, importantly, suggests a need for community-based research, which our team is planning to undertake.