Renal Effects of Environmental Exposure to Cadmium in Middle-Aged Population of Jinzu River Basin in Toyama, Japan: 2000-2002 Study

Abstract

In 2000-2002, the effects of environmental cadmium (Cd) exposure on renal tubular function were investigated in men and women born between January 1, 1946 and December 31, 1955, and living in the Cd-polluted Jinzu River basin in Toyama. It is assumed that these generations had been exposed to Cd mainly through the consumption of rice and vegetables grown locally, in contrast to older generations who had been exposed not only through the consumption of rice but also by drinking river water polluted with Cd discharged from a mine. Morning urine specimens, self-administered questionnaires and polished rice samples consumed daily were collected from 110 men and 121 women living in the polluted area and from 48 men and 45 women living in the reference area. Urinary Cd excretion level, an indicator of Cd accumulation in the kidneys, significantly increased with increased duration (years) of residence in the Cd-polluted area in both men and women. There was no case of urinary beta2-microglobulin (beta2-MG) level exceeding 1,000 microg/g Cr in either sex, in contrast to the high prevalence of beta2-MGuria observed in older generations. However, urinary beta2-MG and alpha1-MG levels were slightly but significantly increased with increased duration (years) of residence in the Cd-polluted area in women. The results indicate that men and women born between 1946 and 1955 and living in the Cd-polluted Jinzu River basin had Cd accumulation in the kidneys and a slight increase in urinary low-molecular weight protein level due to this accumulation.