Dose-response relationship between total cadmium intake calculated from the cadmium concentration in rice collected from each household of farmers and renal dysfunction in inhabitants of the Jinzu River basin, Japan.

The association between total cadmium (Cd) intake and abnormal urinary findings was investigated in the Cd-polluted Jinzu River basin. In 1967 and 1968 the most systematic and large-scale health examinations were conducted among the entire population aged over 30 years of this region. We performed this study by targeting the subjects participating in the 1967 health survey conducted mainly in the heavily polluted area. From subjects who had eaten household rice of known Cd concentration, 1,075 inhabitants who had either resided in their current household since birth or who had moved there from a non-polluted area (group A), and 780 inhabitants who had resided in the current household since birth (group B), were selected as the target population. The total Cd intake for each person was calculated from the Cd dose ingested from rice and other foods. Logistic regression analysis was performed using the prevalence of abnormal urinary findings (proteinuria, glucosuria and proteinuria with glucosuria) as the criterion variable and the total Cd intake and age as explanatory variables. In subjects of groups A and B the odds ratios became higher as the dose of total Cd intake increased. Odds ratios in subjects of group A were statistically significant except for glucosuria of men and proteinuria of women. In subjects of group B the odds ratios were also significant for proteinuria + glucosuria of men and glucosuria of women. It was demonstrated that the greater the increase in total Cd intake, the greater the increase in abnormal urinary findings in the Jinzu River basin, and the association of the two factors was very close.