Occupational exposure to cobalt is not associated with incipient signs of dilated cardiomyopathy in a Belgian refinery.

Background: Excessive absorption of cobalt has been associated with cases of dilated cardiomyopathy in the past, but it is unclear whether occupationally exposed populations are at risk.

Objective: To assess the possible relationship between occupational exposure to cobalt and incipient signs of dilated cardiomyopathy.

Methods: A cross-sectional survey was conducted in a cobalt production facility in Belgium constituting one of the largest occupational populations worldwide (n=256 male workers). Exposure to cobalt was assessed by measuring urinary cobalt concentration (µg/gcreat), reflecting recent exposure, and by computing an integrated exposure index (µg/gcreat×years), reflecting long-term exposure. The effect on the myocardium was investigated by echocardiography and electrocardiography, and dose-effect relations with cobalt exposure were traced by multiple regression analysis.

Results: No dose-effect relationship between exposure to cobalt and parameters reflecting dilated cardiomyopathy was found in a population of workers characterised by a median recent cobalturia of 4 µg/gcreat and a median long-term cobalturia of 100 µg/gcreat×years. A reduction in the dimensions of the left ventricular internal cavity was associated with recent exposure to cobalt.

Conclusions: Occupational exposure to cobalt does not appear associated with incipient signs of dilated cardiomyopathy within the gradient of exposure recorded in this population.