Environmental renal disease: lead, cadmium and Balkan endemic nephropathy.

The similarity of lead and cadmium nephropathy to Balkan endemic nephropathy warrants careful reevaluation of the possibility that these nephrotoxic metals contribute to the production of the endemic renal disease. Low-level environmental exposure may result in a relationship between the concentration of the metals in tissue storage sites and biological fluids that differs from that encountered after occupational exposure. Urine and blood concentrations may therefore be inadequate measures of exposure. Lead is accumulated in the skeleton and cadmium in the liver and kidneys with biological half lives approximating a decade. Non-invasive in vivo x-ray fluorescence or neutron activation analysis can therefore be used to measure cumulative tissue stores. Multiple regression analysis of epidemiologic data could reveal the relative contribution of causal factors, including lead and cadmium, and help to distinguish Balkan endemic nephropathy from other renal diseases using rigorous diagnostic criteria. As long as Balkan endemic nephropathy remains a diagnosis of exclusion, the accuracy of the diagnosis of other renal disease determines the reliability of identification of the endemic disease.