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Background: More than half the cobalt needed for vehicle electrification originates from the southern part of the Democratic Republic of the Congo (DRC), with a substantial part being extracted by artisanal miners., Aims: To investigate oxygen saturation during underground work among cobalt artisanal miners., Methods: In a field survey, we measured oxygen saturation (SpO2) and heart rate by pulse oximetry in 86 miners from two underground mines and 24 miners from a surface mine at four different time points: before descent into the mine (T1), at 50 minutes in the mine (T2), upon leaving the shaft (T3), and 10 minutes after having left the mine (T4)., Results: Miners working underground (-36 to -112 meters) were somewhat older (34.8 ± 6.7 years) than those working in the surface mine (32.0 ± 6.5 years), and they worked more hours daily (12.6 ± 1.2 hours) than controls (9.0 ± 0.0 hours). All participants had SpO2 >95% at T1 and T4. At T2, SpO2 dropped below 93% and 80% in 35% and 10% underground miners, respectively; SpO2 was still <93% at T3 in 13%. SpO2 remained stable among surface miners. Later, we showed that underground ambient oxygen levels decreased well below 21% in several pits., Conclusions: Pulse oximetry revealed relevant hypoxaemia during underground work in a substantial proportion of artisanal miners. Such hypoxaemia without evidence of underlying cardiovascular disease is indicative of low ambient oxygen, due to insufficient mine ventilation. This may cause deaths from asphyxia. The hazards of low ambient oxygen in artisanal mines must be prevented by appropriate technical measures ensuring the supply of sufficient fresh air., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: The African Copperbelt is a site of intense artisanal and industrial mining and refining of copper and cobalt., Aim: We aimed to investigate factors that are possibly associated with erectile dysfunction (ED) in metal miners in the former Katanga province of the Democratic Republic of the Congo., Methods: In a cross-sectional study of 138 miners and 139 controls (bakers), we administered questionnaires to obtain sociodemographic and occupational data and to assess male sexual function (International Index of Erectile Function [IIEF]) and marital relation quality (Revised Dyadic Adjustment Scale). Furthermore, we measured trace metals in blood and urine, as well as testosterone and thyroid hormones in serum., Outcomes: Outcomes included the prevalence of questionnaire-derived ED and the relation of ED with individual characteristics, serum testosterone, and environmental factors., Results: Miners were on average 4 years older than bakers (mean ± SD, 37.5 ± 6.9 vs 33.3 ± 5.7 years). Miners had significantly lower scores than bakers on the IIEF (median [IQR], 66 [49-73] vs 73 [66-74]) and the 3 domains of the Revised Dyadic Adjustment Scale (consensus, satisfaction, cohesion). Free testosterone was significantly lower in miners than bakers (ng/dL; 8.11 [6.90-10.10] vs 10.52 [8.83-12.58]; P ˂ .001). In miners, sex hormone-binding globulin correlated positively with blood Pb and urinary Cd. In a multivariable analysis, mild to moderate ED or moderate ED (IIEF-erectile function score ≤18) was significantly associated with having a mining-related job (adjusted odds ratio [aOR], 2.6; 95% CI, 1.3-5.3), work seniority ˃5 years (aOR, 2.3; 95% CI, 1.1-4.6), alcohol consumption (aOR, 2.8; 95% CI, 1.2-6.7), and aphrodisiacs use (aOR, 4.2; 95% CI, 2.2-8.0). Mediation analysis showed that marital relationship partially mediated the relation between work seniority >5 years in mining and ED., Clinical Implications: The high prevalence of ED found in artisanal mine workers indicates that work-related factors should be considered as possibly contributing, directly or indirectly, to sexual dysfunction in men., Strengths and Limitations: Strengths include being the first epidemiologic study documenting ED with validated questionnaires and its possible determinants, including exposure to toxic metals, among young artisanal miners vs a suitable control group. Limitations are the cross-sectional design with convenience sampling and absence of objective confirmation of ED., Conclusion: As compared with controls, miners reported poorer sexual function and lower quality of their marital relationship, and they had lower free testosterone levels, which may be due to their high exposure to trace metals., Competing Interests: The authors declare that they have no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of The International Society of Sexual Medicine.)