Browsing by Subject "Gold"

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    Public health implications of changing patterns of recruitment into the South African mining industry, 1973–2012: a database analysis
    (BioMed Central, 2017-08-03) Ehrlich, Rodney; Montgomery, Alex; Akugizibwe, Paula; Gonsalves, Gregg
    Background: The triple epidemic of silicosis, tuberculosis and HIV infection among migrant miners from South Africa and neighbouring countries who have worked in the South African mining industry is currently the target of regional and international control efforts. These initiatives are hampered by a lack of information on this population. Methods: This study analysed the major South African mining recruitment database for the period 1973 to 2012 by calendar intervals and demographic and occupational characteristics. Changes in area of recruitment were mapped using a geographic information system. Results: The database contained over 10 million contracts, reducible to 1.64 million individuals. Major trends relevant to health projection were a decline in gold mining employment, the major source of silicosis; increasing recruitment of female miners; and shifts in recruitment from foreign to South African miners, from the Eastern to the Northwestern parts of South Africa, and from company employees to contractors. Conclusions: These changes portend further externalisation of the burden of mining lung disease to home communities, as miners, particularly from the gold sector, leave the industry. The implications for health, surveillance and health services of the growing number of miners hired as contractors need further research, as does the health experience of female miners. Overall, the information in this report can be used for projection of disease burden and direction of compensation, screening and treatment services for the ex-miner population throughout Southern Africa.
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    Open Access
    Public health implications of changing patterns of recruitment into the South African mining industry, 1973–2012: a database analysis
    (2018) Ehrlich, Rodney; Montgomery, Alex; Akugizibwe, Paula; Gonsalves, Gregg
    Abstract Background The triple epidemic of silicosis, tuberculosis and HIV infection among migrant miners from South Africa and neighbouring countries who have worked in the South African mining industry is currently the target of regional and international control efforts. These initiatives are hampered by a lack of information on this population. Methods This study analysed the major South African mining recruitment database for the period 1973 to 2012 by calendar intervals and demographic and occupational characteristics. Changes in area of recruitment were mapped using a geographic information system. Results The database contained over 10 million contracts, reducible to 1.64 million individuals. Major trends relevant to health projection were a decline in gold mining employment, the major source of silicosis; increasing recruitment of female miners; and shifts in recruitment from foreign to South African miners, from the Eastern to the Northwestern parts of South Africa, and from company employees to contractors. Conclusions These changes portend further externalisation of the burden of mining lung disease to home communities, as miners, particularly from the gold sector, leave the industry. The implications for health, surveillance and health services of the growing number of miners hired as contractors need further research, as does the health experience of female miners. Overall, the information in this report can be used for projection of disease burden and direction of compensation, screening and treatment services for the ex-miner population throughout Southern Africa.
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    Open Access
    The timing of tuberculosis after isoniazid preventive therapy among gold miners in South Africa: a prospective cohort study
    (2016) Hermans, Sabine M; Grant, Alison D; Chihota, Violet; Lewis, James J; Vynnycky, Emilia; Churchyard, Gavin J; Fielding, Katherine L
    BackgroundThe durability of isoniazid preventive therapy (IPT) in preventing tuberculosis (TB) is limited in high-prevalence settings. The underlying mechanism (reactivation of persistent latent TB or reinfection) is not known. We aimed to investigate the timing of TB incidence during and after IPT and associated risk factors in a very high TB and HIV-prevalence setting, and to compare the observed rate with a modelled estimate of TB incidence rate after IPT due to reinfection.MethodsIn a post-hoc analysis of a cluster-randomized trial of community-wide IPT among South African gold miners, all intervention arm participants that were dispensed IPT for at least one of the intended 9months were included. An incident TB case was defined as any participant with a positive sputum smear or culture, or with a clinical TB diagnosis assigned by a senior study clinician. Crude TB incidence rates were calculated during and after IPT, overall and by follow-up time. HIV status was not available. Multivariable Cox regression was used to analyse risk factors by follow-up time after IPT. Estimates from a published mathematical model of trial data were used to calculate the average reinfection TB incidence in the first year after IPT.ResultsAmong 18,520 participants (96% male, mean age 41years, median follow-up 2.1years), 708 developed TB. The TB incidence rate during the intended IPT period was 1.3/100 person-years (pyrs; 95% confidence interval (CI), 1.0–1.6) and afterwards 2.3/100 pyrs (95% CI, 1.9–2.7). TB incidence increased within 6months followed by a stable rate over time. There was no evidence for changing risk factors for TB disease over time after miners stopped IPT. The average TB incidence rate attributable to reinfection in the first year was estimated at 1.3/100 pyrs, compared to an observed rate of 2.2/100 pyrs (95% CI, 1.8–2.7).ConclusionsThe durability of protection by IPT was lost within 6–12 months in this setting with a high HIV prevalence and a high annual risk of M. tuberculosis infection. The observed rate was higher than the modelled rate, suggesting that reactivation of persistent latent infection played a role in the rapid return to baseline TB incidence.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-016-0589-3) contains supplementary material, which is available to authorized users.