Urinary β2 microglobulin in the biological monitoring of cadmium workers

Abstract

Urinary β2 microglobulin (β2m) estimation has been added to an existing pre-employment and periodic medical surveillance program for cadmium workers. Pre-employment values were measured in 203 men not occupationally exposed to cadmium. The overall geometric mean was 76 μg/l (adjusted to specific gravity 1016): a significantly higher level of 96 μg/l was found in the specimens stored continually at -20°C after voiding, compared with 73 μg/l in specimens that thawed during transport. Sodium azide had been added to all specimen bottles. Employees exposed to cadmium pigments at various stages of their manufacture had no evidence of raised urinary β2m despite exposures above 50 μg/m3 for up to 11 years. This is believed to be due to the insolubility of these compounds. Five known cases of cadmium induced proteinuria whose exposure ceased up to 15 years ago had raised urinary β2m concentrations. Moderately raised concentrations were found in seven others with a history of cadmium oxide exposure and in whom proteinuria has never been detected. The place of urinary β2m in the health care of cadmium workers is discussed and the question of correct management of a cadmium worker with a high β2m is raised.