Increased urinary beta 2-microglobulin in cadmium exposure: dose-effect relationship and biological significance of beta 2-microglobulin.

A study on the general population from both cadmium-polluted and control areas and on cadmium alloy workers indicates that beta 2-MG in urine is very closely correlated with aging, but it indicates an association with cadmium exposure. However, the age factor is stronger than cadmium exposre in both polluted and control areas among persons without clinical proteinuria. On the other hand, cadmium exposure is most likely correlated with beta 2-MG even in nonpolluted areas. Thus it seems that there is no noneffect level of cadmium dose in affecting the elevation of beta 2-MG in urine. beta 2-MG in serum indicated a very close correlation with cadmium in blood among cadmium alloy workers. This may suggest that an increase of beta 2-MG in both blood and urine in an early stage of cadmium exposure is caused by the increased level of beta 2-MG in blood, which may be a result of stimulation due to cadmium, but not necessarily by the clinical dysfunction of reabsorption of beta 2-MG in the renal.