One hundred and seventy-eight subjects, patients with
Itai-itai disease and their family members, aged 12-87 years living in a
cadmium (Cd)-polluted area in the Jinzu River basin (Cd-exposed group) and 176 controls (control group) were examined. In the Cd-exposed group urinary
trehalase increased with increasing age, urinary
beta 2-microglobulin (beta 2-m) and
retinol-binding protein. Although urinary
cadmium was higher in the Cd-exposed group, no particular correlation was found between urinary
trehalase and urinary
cadmium. Seventeen men and 11 women showed raised urinary
trehalase activities despite normal values of urinary beta 2-m (less than 300 micrograms/g.
creatinine), suggesting that urinary
trehalase increases earlier than urinary beta 2-m. In 19 patients with
Itai-itai disease included in the Cd-exposed group, urinary
trehalase decreased with decreasing reciprocal of serum
creatinine, suggesting that urinary
trehalase decreases in the most advanced cases of chronic
cadmium nephropathy due to reduced tubular cell mass.