Does cadmium contribute to human hypertension

Abstract

In 1962 Schroeder reported marked hypertension in rats chronically fed a very low cadmium diet and 5 ppm cadmium in water, but subsequently he reported only moderate hypertension. Using Schroeder's food and water, but a slightly less cadmium-free environment, we repeatedly induced mild hypertension with 5 ppm cadmium, mild because control pressures were higher not because cadmium-fed animals had lower pressures. Seven laboratories have observed hypertension after feeding cadmium; six have not. Thus, chronically fed cadmium can induce hypertension in rats, but conditions are important. Additional observations on cadmium-induced hypertension indicate that: (1) concentrations from 0.1 to 5 ppm cadmium in water are pressor; (2) sex, strain, and age of animals are apparently not limiting factors; (3) there is associated sodium retention; (4) there is a concomitant decrease in the high energy phosphate content of tissues. Rats with cadmium-induced hypertension have renal cadmium concentrations which bracket those of the average environmentally exposed American or European. Finally, renal cadmium concentrations in man were significantly higher ( p < 0.05) for “hypertensives” than for normotensive “matches” in five of nine reported series, lower in one, and similar in three, with all series being small and suboptimal in subject selection.