APPLICATION OF PATH ANALYSIS TO URINARY FINDINGS OF CADMIUM-INDUCED RENAL DYSFUNCTION

Abstract

In order to identify some causal relations among various urinary indices of cadmium-induced renal dysfunction, such as glucose, total protein, amino nitrogen, β₂-microglobulin (β₂-m), metallothionein (MT), and cadmium (Cd), we applied path analysis method to previous epidemiological studies targeting the residents of the Cd-polluted Kakehashi River basin of Ishikawa Prefecture, Japan. We obtained a diagram-termed path model, representing some causal relations among the above urinary indices. It shows that urinary Cd is located at the beginning point in the diagram, and Cd-induced renal dysfunction develops in the following order: Cd exposure → increase of β₂-m and/or MT excretion → increase of amino-N and/or total protein excretion → increase of glucose excretion. It was proved mathematically, that in the case of both males and females, increased excretions of β₂-m and/or MT were the most sensitive urinary indices of the early stage of chronic Cd-induced renal dysfunction.

Keywords:

• Path analysis
• Causal relation
• Cadmium-induced renal dysfunction
• β₂-Microglobulin
• Metallothionein

Acknowledgments