Those Who Don’t Return: Improving Efforts to Address Tuberculosis Among Former Miners in Southern Africa

Smith, Jonathan; Blom, Paul W. M.

doi:10.1177/1048291119832082

Cited by 33 publications

(10 citation statements)

References 57 publications

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“…Workers on the South African gold mines and particularly black miners have a history of high rates of tuberculosis related to the migrant labour system and deep level gold mining going back 130 years. In addition to silica exposure, this system has entailed oscillation between mines and rural areas and congregate exposures in transport, accommodation and underground work, greatly aggravated by the HIV epidemic from the 1990s onwards [60,61]. Studies are needed from other high tuberculosis burden countries such as India, China, Indonesia and Brazil, to determine if their patterns of risk differ.…”

Section: Overall Completeness and Applicability Of Evidencementioning

confidence: 99%

The association between silica exposure, silicosis and tuberculosis: a systematic review and meta-analysis

et al. 2021

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Background While the association between occupational inhalation of silica dust and pulmonary tuberculosis has been known for over a century, there has never been a published systematic review, particularly of experience in the current era of less severe silicosis and treatable tuberculosis. We undertook a systematic review of the evidence for the association between (1) silicosis and pulmonary tuberculosis, and (2) silica exposure and pulmonary tuberculosis controlling for silicosis, and their respective exposure-response gradients. Methods We searched PUBMED and EMBASE, and selected studies according to a priori inclusion criteria. We extracted, summarised and pooled the results of published case-control and cohort studies of silica exposure and/or silicosis and incident active tuberculosis. Study quality was assessed on the Newcastle-Ottawa Scale. Where meta-analysis was possible, effect estimates were pooled using inverse-variance weighted random-effects models. Otherwise narrative and graphic synthesis was undertaken. Confidence regarding overall effect estimates was assessed using the GRADE schema. Results Nine studies met the inclusion criteria. Meta-analysis of eight studies of silicosis and tuberculosis yielded a pooled relative risk of 4.01 (95% confidence interval (CI) 2.88, 5.58). Exposure-response gradients were strong with a low silicosis severity threshold for increased risk. Our GRADE assessment was high confidence in a strong association. Meta-analysis of five studies of silica exposure controlling for or excluding silicosis yielded a pooled relative risk of 1.92 (95% CI 1.36, 2.73). Exposure-response gradients were observable in individual studies but not finely stratified enough to infer an exposure threshold. Our GRADE assessment was low confidence in the estimated effect owing to inconsistency and use of proxies for silica exposure. Conclusions The evidence is robust for a strongly elevated risk of tuberculosis with radiological silicosis, with a low disease severity threshold. The effect estimate is more uncertain for silica exposure without radiological silicosis. Research is needed, particularly cohort studies measuring silica exposure in different settings, to characterise the effect more accurately as well as the silica exposure threshold that could be used to prevent excess tuberculosis risk.

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Section: Overall Completeness and Applicability Of Evidencementioning

confidence: 99%

The association between silica exposure, silicosis and tuberculosis: a systematic review and meta-analysis

et al. 2021

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“…Like most of the studies of silicosis in the South African mining industry, this analysis is restricted to working miners. Knowledge of the silicosis experience of the large population of black ex-miners, most of who are migrants from rural areas of Southern Africa, is limited [8,9,12,41]. Factors affecting the progression, radiological incidence and prevalence of silicosis in ex-miners include high initial mortality rates [42] and the poorly understood effects of latency from retained dust load and sub-radiological silicosis [43], both of which may result in the first appearance of radiological appearance after exposure has ended.…”

Section: Limitationsmentioning

confidence: 99%

“…High HIV prevalence recorded in migrant miners at a time [12] when coverage of antiretroviral therapy was low, along with ongoing risk of tuberculosis (including recurrent disease) due to HIV and dust, would further shape survival and the associated silicosis prevalence. Health system factors contributing to deficient understanding of the epidemiology of silicosis in ex-miners include lack of surveillance and recognition of silicosis once miners have left the mine [40,41], and relative absence of ex-miners from official autopsy and compensation statistics [44].…”

Section: Limitationsmentioning

confidence: 99%

Predictors of silicosis and variation in prevalence across mines among employed gold miners in South Africa

et al. 2020

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Background: The stated intention to eliminate silicosis from the South African goldmining industry as well as current programmes to find and compensate ex-miners with silicosis require an understanding of variation in silicosis prevalence across the industry. We aimed to identify the predictors of radiological silicosis in a large sample of working miners across gold mines in South Africa. Methods: Routine surveillance chest radiographs were collected from 15 goldmine "clusters" in a baseline survey undertaken in preparation for a separate tuberculosis isoniazid prophylaxis trial. All images were read for silicosis by a health professional experienced in using the International Labour Organisation (ILO) classification. Profusion thresholds of > 1/0 and > 1/1 were used. Demographic and occupational information was obtained by questionnaire. Predictors of silicosis were examined in a multivariable logistic regression model, including age, gender, racial ascription, country of origin, years since starting mine employment, mine shaft, skill category, underground work status and tuberculosis. Results: The crude silicosis prevalence at ILO > 1/1 was 3.8% [95% confidence interval (CI) 3.5-4.1%]. The range across mine shafts was 0.8-6.9%. After adjustment for covariates, the interquartile range across shafts was reduced from 2.4 to 1.2%. Black miners [adjusted odds ratio (aOR) 2.8; 95% CI 1.1-7.2] and miners in full-time underground work (aOR 2.1; 95% CI 1.3-3.4) had substantially elevated odds of silicosis, while workers from Mozambique had lower odds (aOR 0.54; 95% CI 0.38-0.77). Silicosis odds rose sharply with both age and years since starting in the industry (p for linear trend < 0.005), with 95.5% of affected miners having > 15 years since first exposure and 2.2% < 10 years. Conclusions: In surveillance of silicosis in working gold miners time since first exposure remains a powerful predictor. Age appears to be an independent predictor, while the detection of radiological silicosis in short-service miners requires attention. Public risk reporting by mines should include factors bearing on silicosis prevalence, specifically dust concentrations, with independent verification. Studies of silicosis and tuberculosis in ex-miners are needed, supported by an accessible electronic database of the relevant medical and dust exposure records of all gold miners.

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“…In Southern Africa, a powerful legacy of social injustice has been the prevalence of occupational lung disease, particularly silicosis and TB, among the miners who produced so much wealth for the global economy [ 18 19 20 21 22 ]. A dominant feature of the labour system for South Africa’s gold mines has been oscillating migrant labour, with large numbers of migrant miners having left families in Botswana, Lesotho, Mozambique, Eswatini and elsewhere in Southern Africa, along with miners from regions within South Africa such as the Eastern Cape, to work in mines far from home [ 21 22 ].…”

Section: Contextmentioning

confidence: 99%

“…Besides causing silicosis [ 18 19 ], silica inhalation in underground mining and the resultant silicosis increases the risk of active pulmonary TB [ 23 24 ] as well as the risk of post-TB fibrosis [ 24 25 ]. TB is further amplified in this population by the migrant labour system, high prevalence of HIV infection, and crowded transport and living conditions [ 18 20 21 22 26 ]. Importantly, TB can also result in lung changes that mask the appearance of silicosis or mimic it on the CXR, creating problems for diagnosis [ 25 ].…”

Section: Contextmentioning

confidence: 99%

Using Artificial Intelligence for High-Volume Identification of Silicosis and Tuberculosis: A Bio-Ethics Approach

Spiegel

Ehrlich

Yassi

et al. 2021

Annals of Global Health

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Although Artificial Intelligence (AI) is being increasingly applied, considerable distrust about introducing “disruptive” technologies persists. Intrinsic and contextual factors influencing where and how such innovations are introduced therefore require careful scrutiny to ensure that health equity is promoted. To illustrate one such critical approach, we describe and appraise an AI application – the development of computer assisted diagnosis (CAD) to support more efficient adjudication of compensation claims from former gold miners with occupational lung disease in Southern Africa. In doing so, we apply a bio-ethical lens that considers the principles of beneficence, non-maleficence, autonomy and justice and add explicability as a core principle. We draw on the AI literature, our research on CAD validation and process efficiency, as well as apprehensions of users and stakeholders. Issues of concern included AI accuracy, biased training of AI systems, data privacy, impact on human skill development, transparency and accountability in AI use, as well as intellectual property ownership. We discuss ways in which each of these potential obstacles to successful use of CAD could be mitigated. We conclude that efforts to overcoming technical challenges in applying AI must be accompanied from the onset by attention to ensuring its ethical use.

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Those Who Don’t Return: Improving Efforts to Address Tuberculosis Among Former Miners in Southern Africa

Cited by 33 publications

References 57 publications

The association between silica exposure, silicosis and tuberculosis: a systematic review and meta-analysis

The association between silica exposure, silicosis and tuberculosis: a systematic review and meta-analysis

Predictors of silicosis and variation in prevalence across mines among employed gold miners in South Africa

Using Artificial Intelligence for High-Volume Identification of Silicosis and Tuberculosis: A Bio-Ethics Approach

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