Dose-response relationship between urinary cadmium and β2-microglobulin in a Japanese environmentally cadmium exposed population

Abstract

This study was carried out to test the dose-response relationship between urinary cadmium (Cd) and β 2-microglobulin( β 2-mg) and also to estimate the biological threshold value of urinary Cd concentration in inhabitants exposed to environmental Cd. Urinary Cd and β 2-mg were measured in 3178 inhabitants over 50 years of age in the Cd-polluted Kakehashi River basin in Japan and 294 inhabitants in non-polluted areas. Urinary Cd and β 2-mg were significantly higher in the Cd-exposed subjects than in the non-exposed subjects. Prevalance rates of β 2-microglobulinuria( β 2-mg-uria) increased proportionally with increasing urinary Cd concentrations and probit linear regression lines could be calculated between them. The urinary Cd concentration corresponding to the prevalance rates of β 2-mg-uria among non-exposed subjects was calculated using the regression line, and values of 3.8–4.0 μg Cd/g creatinine for men and 3.8–4.1 μg Cd/g creatinine for women, respectively, were obtained. These values may be of used in establishing the biological threshold of urinary Cd concentration in environmentally Cd-exposed populations.