Cadmium levels in the urine of female farmers in nonpolluted areas in Japan.

About 1200 urine samples were collected, mostly in winter seasons in 1982-1984, from adult women in 7 nonpolluted areas in widely separated parts of Japan, and analyses for cadmium (Cd-U) were conducted in a single laboratory. The geometric mean (GM) by decades of age groups of Cd-U, after adjustment for a specific gravity of urine of 1.016, increased from 0.88 microgram/l in the twenties to reach a maximum of 1.78 micrograms/l in the fifties followed by gradual decrease to 1.31 micrograms/l in the eighties. The effect of smoking (about 8 cigarettes/d as a mean) was absent. Analyses of additional 125 urine samples from men revealed that Cd-U in men was not higher than that in women. When classified geographically, Cd-U was higher in the area on the coast of the Sea of Japan, as suspected in preceding studies on blood cadmium levels and dietary cadmium intakes. The Cd-U levels observed in the present study are similar to the values in previous publications on the Japanese and are apparently higher than the counterpart values from Europe, the United States, and New Zealand.