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

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dc.contributor.authorKnight, Dave
dc.contributor.authorEhrlich, Rodney
dc.contributor.authorCois, Annibale
dc.contributor.authorFielding, Katherine
dc.contributor.authorGrant, Alison D
dc.contributor.authorChurchyard, Gavin
dc.date.accessioned2020-06-11T15:27:17Z
dc.date.available2020-06-11T15:27:17Z
dc.date.issued2020-06-01
dc.date.updated2020-06-07T03:46:09Z
dc.description.abstractBackground 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.en_US
dc.identifier.apacitationKnight, D., Ehrlich, R., Cois, A., Fielding, K., Grant, A. D., & Churchyard, G. (2020). Predictors of silicosis and variation in prevalence across mines among employed gold miners in South Africa. <i>BMC Public Health</i>, 20(1), 829. http://hdl.handle.net/11427/32064en_ZA
dc.identifier.chicagocitationKnight, Dave, Rodney Ehrlich, Annibale Cois, Katherine Fielding, Alison D Grant, and Gavin Churchyard "Predictors of silicosis and variation in prevalence across mines among employed gold miners in South Africa." <i>BMC Public Health</i> 20, 1. (2020): 829. http://hdl.handle.net/11427/32064en_ZA
dc.identifier.citationKnight, D., Ehrlich, R., Cois, A., Fielding, K., Grant, A.D. & Churchyard, G. 2020. Predictors of silicosis and variation in prevalence across mines among employed gold miners in South Africa. <i>BMC Public Health.</i> 20(1):829. http://hdl.handle.net/11427/32064en_ZA
dc.identifier.risTY - Journal Article AU - Knight, Dave AU - Ehrlich, Rodney AU - Cois, Annibale AU - Fielding, Katherine AU - Grant, Alison D AU - Churchyard, Gavin AB - 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. DA - 2020-06-01 DB - OpenUCT DP - University of Cape Town IS - 1 J1 - BMC Public Health KW - Silicosis KW - Tuberculosis KW - Gold mining KW - South Africa LK - https://open.uct.ac.za PY - 2020 T1 - Predictors of silicosis and variation in prevalence across mines among employed gold miners in South Africa TI - Predictors of silicosis and variation in prevalence across mines among employed gold miners in South Africa UR - http://hdl.handle.net/11427/32064 ER -en_ZA
dc.identifier.urihttps://doi.org/10.1186/s12889-020-08876-2
dc.identifier.urihttp://hdl.handle.net/11427/32064
dc.identifier.vancouvercitationKnight D, Ehrlich R, Cois A, Fielding K, Grant AD, Churchyard G. Predictors of silicosis and variation in prevalence across mines among employed gold miners in South Africa. BMC Public Health. 2020;20(1):829. http://hdl.handle.net/11427/32064.en_ZA
dc.language.rfc3066en
dc.rights.holderThe Author(s)
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en_US
dc.sourceBMC Public Healthen_US
dc.source.journalissue1en_US
dc.source.journalvolume20en_US
dc.source.pagination829en_US
dc.source.urihttps://bmcpublichealth.biomedcentral.com/
dc.subjectSilicosisen_US
dc.subjectTuberculosisen_US
dc.subjectGold miningen_US
dc.subjectSouth Africaen_US
dc.titlePredictors of silicosis and variation in prevalence across mines among employed gold miners in South Africaen_US
dc.typeJournal Articleen_US
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