Dietary cadmium intakes of farmers in nonpolluted areas in Japan, and the relation with blood cadmium levels.

During a period of 1977 to 1981, 24-hr duplicates of daily diets were collected nationwide in 49 regions in 21 prefectures in Japan. More than 1000 samples were obtained in winter from the inhabitants (predominantly farmers) of areas with no known environmental pollution, together with more than 200 additional samples in the immediately preceding or succeeding summer. Cadmium contents (analyzed by wet digestion-flameless atomic absorption spectrophotometry) in the winter diet samples distributed log--normally with males and females giving results (geometric mean (geometric standard deviation] of 43.9 micrograms/day (1.86) and 37.0 micrograms/day (1.85) for 368 and 674 samples, respectively; the difference was statistically significant (P less than 0.01). A slight reduction (ca. 13% in males and 21% in females) in cadmium content was observed in summer diets as compared with winter ones. In winter samples, cadmium levels in diets correlated significantly (P less than 0.01) with the cadmium levels in blood when the results from the examinees of the same survey region were pooled and the two levels were compared in terms of geometric means. Correlation on the individual basis was not remarkable, probably due to day-by-day variation in diet constituents as well as cadmium contents. High cadmium intakes of over 150 micrograms/day were recorded in some cases but did not associate with high cadmium levels in blood.