Early detection of nephrotoxic effects due to low-dose exposure of cadmium among cigarette smokers.

The effects of low-level exposure to cadmium due to cigarette smoking on renal function were judged by the estimation of urinary levels of total proteins, cadmium, alpha-1-microglobulin (alpha1M) and glutathione S-transferase (GST) activity among 50 males (38 smokers and 12 control non-smokers). Elevated urinary cadmium levels [2.408-28.160; 9.31 +/- 7 .1 microg Cd/gm urine creatinine] were observed among the majority of smokers (24 cases, 63.16%) and these levels showed a positive correlation with age and smoking index. Furthermore, urine total proteins [115.18-652.14; 242.89 +/- 121.88 mg protein/gm urine creatinine) were increased suggesting glomerular involvement among 20 cases (52.63%) of smokers. In addition, urinary alpha1M levels (14.645-86.053; 34.05 +/- 16.83 mg alpha1M/gm urine creatinine) and urinary GST activity [0.0-0.008; 0.00015 +/- 0.0002 micromol/min/100 microl/gm urine creatinine] were elevated among 18 (47.37%) and 20 (52.63%) cases of smokers respectively. Since urinary alpha1M and GST originate from renal proximal tubules, the data of the present investigation could reflect early low-level cadmium exposure nephrotoxic effect on both the glomeruli and tubules.