This is presently poorly understood and is likely a function of the free ion Co2+, rather than that bound to other substances such as albumin. A review suggests cardiomyopathy and vision or hearing impairment, are reported at peak blood Co concentrations over 700 µg/L (8-40 weeks). Hypothyroidism and polycythaemia occur with briefer exposures with serum levels above 300 µg/L. The MHRA recommend yearly monitoring of blood levels in those with certain metal to metal implants. Perhaps one should not get too concerned with levels less than 300 µg/L but we do not know and will await the long term results of the monitoring exercise on approximately 1 million patients world wide who started their potential exposure between 2001 and 2010 by receiving metal on metal implants.
- ↑ Gilbert CJ, Cheung A, Butany J, Zywiel MG, Syed K, McDonald M, Wong F, Overgaard C. Hip pain and heart failure: the missing link. The Canadian journal of cardiology. 2013 May; 29(5):639.e1-2.(Link to article – subscription may be required.)
- ↑ Paustenbach DJ, Tvermoes BE, Unice KM, Finley BL, Kerger BD. A review of the health hazards posed by cobalt. Critical reviews in toxicology. 2013 Apr; 43(4):316-62.(Link to article – subscription may be required.)
- ↑ Paustenbach DJ, Galbraith DA, Finley BL. Interpreting cobalt blood concentrations in hip implant patients. Clinical toxicology (Philadelphia, Pa.). 2014 Feb; 52(2):98-112.(Link to article – subscription may be required.)