Non-malignant silica-related diseases in a specialized outpatient clinic

Abstract

Background Uncontrolled occupational exposure to silica is still frequent in Brazil, with several recent records in the state of Minas Gerais. However, few national studies have addressed silica-related diseases other than silicosis. Aims To describe the occurrence of the main non-malignant silica-related diseases: silicosis, tuberculosis (TB), chronic obstructive pulmonary disease (COPD), and autoimmune diseases in a specialized outpatient clinic. Methods Case series study of 1525 patients exposed to silica, seen between 1984 and 2021, with descriptive findings of clinical and occupational data from the first medical evaluation. Results Medians of age and exposure time were 47 and 15 years, respectively, and 97% of patients were male. The prevalence of silicosis was 44%, of which 27% had large opacities. The main occupational sectors were underground gold mining (28%), precious and semi-precious stone work (20%), and artisanal mining (9%). Spirometries were abnormal in 55%, with obstructive disorder being the most common finding. COPD (25%), active TB or sequelae (12%), and connective tissue diseases (6%) were diagnosed in patients with and without silicosis. Conclusions The percentage of silicosis appears to be alarming, even considering the biases of selective referrals. The patients were relatively young and already had a functional impact, caused not only by silicosis but by one or more silica-related diseases. COPD, TB, and connective tissue diseases proved to be frequent, leading to the need for specifics protocols to investigate them in individuals exposed to silica. By adopting strategies to combat silicosis, the prevention of other silica-related diseases is concomitantly promoted.

Association between silicosis and autoimmune disease

“…In Brazil, silicosis is the most frequent pneumoconiosis and represents the main cause of disability among occupational respiratory diseases [11]. A retrospective observational case series study was performed in order to detect nonmalignant silica-related diseases in a specialized outpatient clinic using primary data obtained from the medical assessments of all silica-exposed patients evaluated at the Workers Health Service of the Clinics Hospital of Federal University of Minas Gerais, from 1984 to 2021 [12]. The main occupational sectors were underground gold mining (28%), precious and semi-precious stone work (20%), and artisanal mining (9%).…”

Silica-associated lung disease in developing countries

“…Other respiratory diseases such as emphysema and pleural effusion were diagnosed in 4.3% of the workers [57 ▪ ]. A Brazilian study found a silicosis prevalence of 44% among 1525 patients exposed to silica, of whom 27% had large opacities [48]. Spirometry was abnormal in 55%, with an obstructive defect being the most common finding.…”

“…Silicosis has been reported in India amongst workers involved in mining, sandstone quarrying, stone-cutting, agate grinding, emery polish, jewellery polishing, flour mills and the manufacture of slate pencil, glass, Teflon-coated utensils and ceramic [35–43]. Similarly, silicosis hotspots exist in gold mining in South Africa and Brazil, gemstone manufacturing in China and Brazil, artificial stone processing in China, and denim and Teflon sandblasting in Turkey [44–48]. As a wide variety of occupations involve silica exposure, there are more than 23 million and 10 million workers at risk for silicosis in China and India, respectively [49 ▪▪ ,50].…”