Variation of cadmium accumulation among Japanese.

Human liver, renal cortex, and heart muscle from 394 autopsied Japanese who had lived in eight districts of Japan were sampled. Subjects included 200 males between 0 to 89 yr of age and 194 females between 0 to 94 yr of age. Cadmium, copper, and zinc in both liver and renal cortex, as well as cadmium in heart muscle were compared by district, sex, age, and smoking habits. Statistical results revealed that the difference of each heavy metal distribution by eight districts is significant and that cadmium and zinc levels in liver and renal cortex sampled from north-central Japan were the highest. This probably results from the larger intake of dietary cadmium and zinc via rice since this area is known as one of the better rice growing regions in Japan. Although there is a lack of precise information on smoking habit, cadmium in liver and zinc in liver and renal cortex of males smoking eight or more cigarettes per day were statistically higher than that of nonsmokers and those who smoked less than seven cigarettes per day. However, cadmium in renal cortex was not significant between the two smoking groups. Further studies should be performed to determine the health significance of an increased intake of cadmium by populations from the viewpoint of global biogeochemistry.