A judgment of attribution of increase in urine beta 2-microglobulin after environmental cadmium exposure

Urine beta 2-microglobulin (beta 2-m) was measured in 433 persons with low-level, long-term environmental exposure to Cd, and in 124 control persons from unpolluted area. In 152 of the exposed persons, and some of the controls, the urine beta 2-m exceeded the limit. Of the 433 exposed persons, 74 cases with both urine Cd and beta 2-m exceeding the limit were matched by the control. This study suggests that after the stratification of the degrees of renal tubular injury according to the fractional beta 2-m excretion (FE beta 2-m) and coordination of clinical examination, FE beta 2-m could contribute to identifying renal tubular dysfunction due to Cd exposure and kidney lesion when both Cd exposure and original nephropathy exist.