ABSTRACT
OBJECTIVE: To evaluate silicosis diagnosed through CT, with integration of clinical-occupational data, in silica-exposed workers presenting chest X-rays within International Labor Organization (ILO) category 0. METHODS: Cross-sectional study with 339 former gold miners, with comparable exposures and X-rays classified as ILO subcategory 0/0 (n=285) and 0/1 (n=54) were submitted to volume-based CT. The findings were classified according to the International Classification of HRCT CT for Occupational and Environmental Respiratory Diseases. RESULTS: A profusion degree of round opacities (RO)>1 was found in 22.4% (76/339) of the CT exams. After integrating the CT findings with clinical and occupational data, silicosis was diagnosed as follows: 43/285 (15.1%) and 14/54 (25.9%) in workers whose X-rays had been classified as 0/0 and 0/1, respectively. There was an upward trend towards longer exposures, reaching 38.9% when working more than 10 years underground and classified as 0/1 (p=0019). Those with presence of RO whose final diagnosis was not silicosis were mainly cases of tuberculosis or 'indeterminate nodules'. Emphysema was found in 65/339 (19.1%), only 5 being detected in the X-ray. CONCLUSION: Volume-based CT proved to be useful in the investigation of silicosis among individuals with a relevant exposure to silica, capturing diagnoses that had not been identified on X-rays. A response gradient of silicosis was showed by CT even in this population with ILO category 0 radiographs. It can be indicated based on quantitative and/or qualitative criteria of occupational exposure, especially considering the possibilities of low CT dosage.
Subject(s)
Occupational Exposure , Silicosis , Cross-Sectional Studies , Gold , Humans , Occupational Exposure/adverse effects , Occupational Exposure/analysis , Silicon Dioxide/adverse effects , Silicosis/diagnostic imaging , Silicosis/etiology , TomographyABSTRACT
Resumo Introdução: Minas Gerais é o estado brasileiro com maior registro de casos de silicose, sendo grande parte proveniente de casuísticas acumuladas das minerações de ouro. Objetivos: descrever e analisar temporalmente a ocorrência de silicose na mineração de ouro identificando fatores ocupacionais relacionados. Métodos: estudo transversal com 1.020 ex-mineiros da região de Nova Lima/MG, avaliados entre 1995 e 2011. Resultados: o diagnóstico de silicose foi confirmado em 19,7% dos avaliados. Nenhum caso da doença foi identificado em indivíduos que trabalharam apenas na superfície. A prevalência no grupo que trabalhou até 5 anos no subterrâneo foi de 3,8% e no grupo com mais de 20 anos de trabalho nesse local foi de 44,2%. Os admitidos para trabalho subterrâneo até 1950 apresentaram prevalência de 57,9%. Entre os admitidos após 1990, não houve registro de casos. Conclusão: verificou-se uma queda expressiva na ocorrência de silicose no período analisado. Uma vez que a doença é sabidamente dose-dependente, é esperado que a diminuição dos níveis de exposição, obtido pelas melhorias dos ambientes ocupacionais, tenha refletido nestes resultados. É fundamental que tais medidas continuem a ser adotadas na mineração e em outros ramos de atividade visando reduzir a ocorrência da doença.
Abstract Introduction: Minas Gerais is the Brazilian state with the highest record of silicosis cases, mostly from gold mining. Objectives: to describe and analyze the occurrence of silicosis in gold mining over time, identifying occupational related factors. Methods: cross-sectional study with 1.020 former miners from the region of Nova Lima, Minas Gerais, evaluated from 1995 to 2011. Results: silicosis diagnosis was confirmed in 19.7% of the miners evaluated. No cases were identified in individuals who worked only on the surface. The prevalence among those who worked underground was 3.8% for the group up to 5 years and 44,2% for the group that worked over 20 years. Those admitted to work underground up to 1950 had a prevalence of 57.9%. Among those admitted after 1990, there were no cases recorded. Conclusion: we found an expressive decline in the silicosis occurrence in the period. Because silicosis is dose-dependent, it is expected that decrease in exposure levels was due to improvements in work environments. These measures must continue to be adopted in mining and in other branches of work activity to reduce the occurrence of silicosis.
