A Prospective Study of Proteinuria in Cadmium Workers

Abstract

In man, the kidney is the critical organ following chronic exposure to Cd. An increased urinary excretion of plasma proteins usually represents the earliest biological sign of Cd interference with kidney function. Cadmium can decrease the tubular reabsorption of low molecular weight proteins (< 40, 000 dalton), such as ß2-m and RBP, and it can also enhance the glomerular filtration of high molecular weight proteins (> 40, 000 dalton), such as albumin, representing also an early manifestation of excessive cadmium exposure (Lauwerys et al., 1974 and 1984). The health significance of an increased urinary excretion of specific plasma proteins (e.g. ß2-m, RBP, albumin) without clinical proteinuria which may be found in workers chronically exposed to Cd, remains a matter of controversy (Lauwerys and Bernard, 1986). We have followed up 23 male workers with such renal changes at the time of their removal from exposure to Cd in order to assess whether these early toxic effects of exposure to Cd were predictive of an accelerated decline in renal function.