Browsing by Subject "Miners"

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    Determinants of functional capacity and work ability post SARS-COV-2 infection in miners
    (2025) Ndlovu, Vusimuzi; Jeebhay, Mohamed; Ntatamala, Itumeleng
    Background: Insufficient data exists on the sequelae of COVID-19 and its impact on function and work ability among workers. The aim of this study was to investigate the determinants of functional capacity and work ability in miners following COVID-19 disease. Methods: This cross-sectional study recruited 204 mine workers employed at a ferromanganese mine in the Northern Cape province of South Africa with a confirmed laboratory diagnosis of COVID-19 within the past 12 months. Study instruments included a socio-demographic questionnaire, Post COVID-19 Functional Scale (PCFS), Work Ability Index (WAI), chest radiograph and the Two-minute Walk Test (TMWT). Data analysis was done using STATA version 16 to generate univariate and multivariate quantile regression models. Results: The majority (74%) of the participants were males with a mean age of 38.8 years and employed in the mining department (46%) as operators. A third were current smokers (35%), and obese (36%). The most commonly reported acute COVID-19 symptoms were sore throat (56%), cough (43%), and anosmia (34%). Almost all the participants had reported having two or more episodes of COVID-19 which was of a mild form (64%). Most (86%) returned to work within 14 days of diagnosis. None of the miners had an abnormal PCFS score, nor did they have poor WAI scores. Aside from living arrangements (living with a spouse), none of the socio-demographic or occupational factors were associated with COVID-19 disease severity. Unlike for COVID-19 disease, female sex was significantly associated (p<0.001) with poor performance on the TMWT in the simple regression models. After adjusting for disease severity and sex in the multivariate models, no significant association was observed between COVID-19 disease and the TMWT distance. Conclusion: This study found limited evidence of impaired functional capacity and work ability in miners following COVID-19 disease within one year of SARS-CoV-2 infection. Furthermore, only female sex, but not COVID-19 was associated with impaired functional ability.
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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.