Serum bone-type alkaline phosphatase activity in women living in a cadmium-polluted area.

To clarify the significance of elevated serum total alkaline phosphatase activity (t-ALP) in persons exposed to environmental cadmium (Cd), the fraction of ALP originating from bone (b-ALP) was assayed using a wheat-germ agglutinin method in 23 men and 20 women in a Cd-polluted area who showed excessive urinary beta 2-microglobulin excretion, and in 21 men and 44 women in a non-polluted area, in addition to 7 patients with itai-itai disease. The fraction of b-ALP increased linearly with the increase in t-ALP in the women, irrespective of Cd-exposure. Elevations of both t-ALP and b-ALP in the Cd-exposed women, including inhabitants of the Cd-polluted area and patients with itai-itai disease, were found with decreases in serum calcium and bone density. It is concluded that elevated serum ALP levels found in Cd-exposed persons reflect the development of Cd-induced bone damage.