Bone manganese as a biomarker of manganese exposure: A feasibility study

BACKGROUND: There is a need for a diagnostic tool with the ability to measure cumulative exposure to manganese (Mn) in the workplace. Measuring bone Mn levels with in vivo neutron activation analysis (IVNAA) could serve as a biomarker of past exposure. Bone Mn levels of welders were measured and compared to the levels found in subjects without exposure to the element. METHOD: Forty subjects (30 welders and 10 controls) were recruited. An occupational history was obtained and subjects underwent IVNAA bone Mn measurements. RESULTS: The mean bone Mn levels were (2.9 +/- 0.4) and (0.1 +/- 0.7) microg Mn/g Ca for welders and controls, respectively (P < 0.05). CONCLUSIONS: This project, the first of its kind, reports differences in bone Mn between Mn-exposed welders and non-occupationally exposed subjects. It appears that bone Mn levels do reflect differences in the occupational exposure of welders.