Environmental Silica Dust Exposure and Pulmonary Tuberculosis in Johannesburg, South Africa

Occupational crystalline silica dust exposure is associated with an elevated risk of pulmonary tuberculosis (PTB). However, there is less evidence for an association with environmental silica dust exposure. A cross-sectional study of 310 participants was conducted in an exposed community living within 2 km of gold mine tailings and an unexposed population residing more than 10 km from the nearest gold mine tailing. Chest radiographs ( = 178) were read for PTB, past or current, by three readers. Past or current PTB was radiologically identified in 14.4% (95%CI 9.2-21.8) in the exposed and 7.5% (95%CI 2.8-18.7) in the unexposed groups. Multivariate logistic regression models suggested that PTB prevalence was independently associated with exposure to second-hand smoke (OR = 8.13, 95%CI 1.16-57.22), a lower body mass index (OR = 0.88, 95%CI 0.80-0.98), previous diagnosis and treatment of PTB (OR = 8.98, 95%CI 1.98-40.34), and exposure to dust in the workplace from sand, construction, and/or mining industries (OR = 10.2, 95%CI 2.10-50.11). We found no association between PTB and environmental exposure to gold mine tailing dust. However, workplace silica dust exposure is a significant risk factor for PTB in South Africa, and PTB patients of working age should be screened for silica exposure.