抄録
Since1972, we have conducted health examinations on the residents in Hosogoe area, Kosaka town, Akita prefecture, one of the environmentally cadmium-polluted areas in Japan, Estimation of the corrected urinary β2-microglobulin concentration (corrected u-β2 mg) -urinary β2-micro globulin per 1 g of urinary creatinine-, and the proximal renal tubular function tests (% TRP, Cua/Ccr, tubular proteinuria, renal glucosuria, and urinary total amino nitrogen per 1 g of urinary creatinine) were done at the same time on 25 residents in this area. There was a close relationship between the corrected u-β2 mg and the results of the proximal renal tubular function tests. As these results were judged to be mostly caused by proximal renal tubular damage, we established that the corrected u-β2 mg was a valuable index of proximal renal tubular damage. For 215 residents in the Hosogoe area (males 98, females 117, 3-85 years, 79.6 % of target population), the average corrected u-β2 mg of each age group tended to be elevated with age, and was higher than that of the control group for the same age. This difference also had a tendency to increase with age, and a statistically significant difference was found in every decade from the 2 nd to the 9 th. These findings were suspected as a result of the proximal renal tubular damage induced by the environmental cadmium pollution. There was a statistically significant correlation between the mean years of residence for each age group in the Hosogoe area and the average corrected u-β2 mg. As total intake of cadmium of each resident in the Hosogoe area was supposed to be directly proportional to the years of residence, we concluded that there was "Dose-Effect Relationships" between the total intake of cadmium and the degree of proximal renal tubular damage induced by cadmium. There was a statistically significant difference between the average corrected u-β2 mg of each age group in the Hosogoe area whose mean years of residence was over 15 years and that of the control group for the same age. As cadmium intake of the residents in the Hosogoe area was calculated at about 1 g for 15 years, we suspected that proximal renal tubular damage might occur in the people who had taken cadmium over 1 g for 15 years. Because the increase of urinary excretion of β2-microglobulin in females was supposed to be greater than that in males in the Hosogoe area, we suspected that the proximal renal tubular damage induced by cadmium might occur more easily in females than in males.
