Absence of adverse effect on thyroid function and red blood cells in a population of workers exposed to cobalt compounds.

CONTEXT: Hypothyroidism has been observed in the fifties and sixties as an undesirable side-effect of cobalt therapy used for its erythropoietic properties in the treatment of anemia. OBJECTIVE: This study aims at evaluating the possible impact of both cumulative (long-term) and recent occupational exposure to cobalt on thyroid function and red blood cells. METHODS AND SETTING: A cross-sectional survey was conducted from February 2008 to August 2009 in a population of 249 male workers from a cobalt production department in the North of Belgium. The possible effect of cobalt exposure on thyroid and red blood cells was investigated through multiple regression analyses. RESULTS: Blood cobalt ranged from undetectable to 3.20 µg/100ml (median 0.10); urinary cobalt from 0.30 to 204.30 µg/g(creat) (median 3.90) and long-term exposure to cobalt ranged from 0.15 to 6990.46 µg/g(creat) · years (median 106.09). No effect of cobalt exposure on thyroid or red blood cell parameters was observed at these levels of exposure. CONCLUSION: The results support the absence of effects on the thyroid and red blood cells when occupational exposure to cobalt is kept below the recommended biological limit of occupational exposure (15 µg Co/g(creat) in urine).

Epidemiological survey of workers exposed to inorganic germanium compounds.

OBJECTIVES: To assess occupational exposure to inorganic germanium (Ge) in workers from a producing plant, and to assess the health of these workers, with a special focus on respiratory, kidney, and liver functions. METHODS: Cross sectional study of 75 workers exposed to Ge and 79 matched referents. Exposure was characterised by measuring air and urine concentrations of the element during a typical working week, and health was assessed by a questionnaire, clinical examination, lung function testing, chest radiography, and clinical chemistry in serum and urine, including high and low molecular weight urinary proteins. RESULTS: Airborne concentrations of Ge (inhalable fraction) ranged from 0.03 to 300 micrograms/m, which was reflected by increased urinary excretion of Ge (0.12-200 micrograms/g creatinine, after the shift at the end of the working week). Lung, liver, and haematological variables were not significantly different between referents and workers exposed to Ge. A slightly higher urinary concentration of high molecular weight proteins (albumin and transferrin) was found in workers exposed to Ge, possibly reflecting subclinical glomerular changes. No relation was found between the intensity or duration of exposure and the urinary concentration of albumin. No difference between referents and workers exposed to Ge was found for other renal variables. CONCLUSIONS: Measurement of urinary Ge can detect occupational exposure to inorganic Ge and its compounds. It is prudent to recommend the monitoring of renal variables in workers exposed to Ge.