Johannesburg: The incidence of active pulmonary tuberculosis (PTB) and silicosis among gold miners remains high, but recent years have seen a slow decline in the rates of both diseases, according to a recent study. The findings from the study titled ‘Surveillance of Occupational Lung Diseases at Autopsy in South African Miners, 2021’ suggest that this drop may be attributed to improved silica dust control measures, better living conditions, and the rollout of antiretroviral therapy (ARTs).
According to South African Government News Agency, the study is based on the annual Pathology Computerised Pathology Automation System (PATHAUT) surveillance report. The Pathology Division of the National Institute for Occupational Health (NIOH), a division of the National Health Laboratory Service (NHLS), examines the cardiorespiratory organs of deceased miners and ex-miners.
The lead author, Thembi Mashele, explained that the research aimed to assess the prevalence of occupational respiratory diseases in miners at autopsy in 2021 and highlight key trends for South Africa. In 2021, 546 cardiorespiratory organs from deceased miners and former miners in South Africa were examined. The autopsies were conducted on 303 (55.5%) Black miners, 241 (44.1%) White miners, and two (0.4%) mixed-race miners.
The miners had an average age of 51.6 years, with White miners being slightly older than Black miners. Most cases came from Gauteng, followed by the North West province. The deceased miners worked in various mining sectors, with the majority having experience in the gold mining industry. Emphysema, active PTB, and silicosis were the most frequently occurring occupational diseases diagnosed at autopsy.
The study revealed that the current active PTB rate was 137 cases per 1,000 autopsies, higher than the 1995 rate of 93 per 1,000. Rates of silicosis in Black and White miners remained above 200 per 1,000 compared to 182 per 1,000 in 1995. Research revealed that the number of autopsies conducted at the NIOH has declined over the years, peaking in 1995 with 4,003 cases compared to 546 in 2021.
The study also found a drop in the number of miners coming to autopsy, potentially reducing access to compensation for families. “This decrease also hinders the documentation of detailed findings for the surveillance and research of respiratory diseases associated with mining and environmental exposures,” said Mashele.
Mashele stated that asbestos mining ended in South Africa in 2002. However, due to the long latency of asbestos-related diseases, respiratory issues among miners exposed to asbestos are expected to persist. Environmental asbestos exposure-related cases will also be anticipated as asbestos remains present in the environment and buildings.
The government provides compensation to the families of deceased miners diagnosed with certified compensable diseases, including silicosis, coal worker’s pneumoconiosis, mixed dust fibrosis, chronic obstructive pulmonary disease, lung cancer, PTB, asbestos-related diseases, and progressive systemic sclerosis excluding skin-related conditions.
“Due to a decline in numbers seen over the years, we hope to raise awareness amongst healthcare professionals and the public about the surveillance of occupational respiratory diseases and the key trends observed since 1975,” Mashele added. Since 1975, demographic information, clinical causes of death, occupational histories, and pathological findings related to cardiorespiratory organs of miners have been documented in a computerised PATHAUT database, which contained a total of 115,339 records by the end of 2021.
The study has recommended continued policy implementation to control dust in the mining industry, leading to reductions in the incidence of occupational respiratory diseases. Researchers advocated for compliance with the International Labour Organisation and the World Health Organisation’s Global Programme for the Elimination of Silicosis efforts to eradicate silicosis by 2030. Employers are encouraged to perform continuous air monitoring and submit regular reports to the Department of Mineral Resources.
“The ongoing systematic monitoring of trends will support the evaluation of interventions and the attribution of research in respiratory diseases confounded by smoking for compensation,” the study concludes.