Blood cadmium levels in the populations of Masan, Korea, and Miyagi, Japan: an inter-regional comparison.

Blood samples were collected from factory workers (with no occupational exposure to metals including cadmium) in Masan (167 subjects), Korea, in 1986, and Miyagi prefecture (270 subjects) Japan, in 1987. The samples were analyzed for cadmium in a single laboratory by flameless atomic absorption spectrophotometry under strict quality control. The effect of aging was detected in Masan and possibly also in Miyagi. The effect of smoking was evident among male smokers in Miyagi. Comparison with findings in a sister study on blood cadmium levels in China (taking the effects of smoking and aging into account) showed regional differences: the levels were lower in China, higher in Korea and probably highest in Japan. The smoking-associated increase in blood cadmium level per cigarette was 2-3 times higher in China than in Japan. The blood cadmium levels in the study regions appeared to be associated with the cadmium content of local rice as well as with local rice-eating habits.