Cadmium cause and effect: looking at renal function. (Science Selections).Exposure to high concentrations of cadmium cadmium (kăd`mēəm) [from cadmia, Lat. for calamine, with which cadmium is found associated], metallic chemical element; symbol Cd; at. no. 48; at. wt. 112.41; m.p. 321°C;; b.p. 765°C;; sp. gr. 8. , as in industrial settings, can lead to renal failure renal failure n. Acute or chronic malfunction of the kidneys resulting from any of a number of causes, including infection, trauma, toxins, hemodynamic abnormalities, and autoimmune disease, and often resulting in systemic symptoms, especially edema, , but kidney problems can arise even from low-level cadmium exposures. In this month's issue, a group of scientists led by Ing-Marie Olsson of the Swedish University of Agricultural Sciences The university has four faculties: Faculty of Landscape Planning, Horticulture and Agricultural Science, Faculty of Natural Resources and Agriculture Sciences, Faculty of Veterinary Medicine and Animal Science and Faculty of Forest Sciences. investigates the relationship between cadmium intake from various sources, cadmium retention, and kidney function [EHP EHP abbr. 1. effective horsepower 2. electric horsepower 110:1185-1190]. They found that, although most of the subjects had relatively low cadmium intake, the cadmium did appear to have an adverse effect on kidney function. The study subjects were heterosexual couples living on farms in the Skane province of southern Sweden. The soil in this area is relatively high in cadmium. Some of the cadmium occurs naturally, some comes from phosphate fertilizers once used intensively in farming, and some comes from clouds of industrial pollution originating in central Europe Central Europe is the region lying between the variously and vaguely defined areas of Eastern and Western Europe. In addition, Northern, Southern and Southeastern Europe may variously delimit or overlap into Central Europe. . Demographic and lifestyle factors may affect how people are exposed nonoccupationally to cadmium. For example, nonsmokers absorb most of their cadmium from food and water, but because tobacco draws cadmium from soil, smokers may absorb half their exposure from cigarettes. The researchers surveyed the subjects on their diets and smoking habits. They estimated the amount of cadmium the subjects ingested in·gest tr.v. in·gest·ed, in·gest·ing, in·gests 1. To take into the body by the mouth for digestion or absorption. See Synonyms at eat. 2. through foods and assigned cadmium values to these different eating patterns, based on existing literature. They also calculated the amount of cadmium the subjects got from water by measuring the metal in the subjects' wells and estimating the amount of water, tea, coffee, and juice they drank. Even at the lowest exposure level, there was an indication of effect on kidney function, and higher concentrations of urine cadmium (UCd) correlated to reduced kidney performance. As expected, the researchers found that individuals with high blood cadmium (BCd) also had high UCd. However, cadmium consumption did not correlate with UCd or BCd, a finding that has been previously reported at low exposures. This may be because of the subjects' low average dietary intake of cadmium, because of variation in the bioavailability bioavailability /bio·avail·a·bil·i·ty/ (bi?o-ah-val?ah-bil´i-te) the degree to which a drug or other substance becomes available to the target tissue after administration. bi·o·a·vail·a·bil·i·ty n. of the cadmium in the subjects' food and water, or because of uncertainties in the estimated intake of cadmium from food. The women's BCd was about 1.4 higher than that of the men, and their UCd was about 1.6 times higher than the men's. In a subgroup sub·group n. 1. A distinct group within a group; a subdivision of a group. 2. A subordinate group. 3. Mathematics A group that is a subset of a group. tr.v. of the sample--couples in which neither person had ever been a smoker--the women had lower intakes per body weight of cadmium than men, but had 1.8 times higher BCd and 1.4 times higher UCd. This may be due, the researchers say, to the lower iron status typical of premenopausal pre·me·no·paus·al adj. Of or relating to the years or the stage of life immediately before the onset of menopause. premenopausal adjective women, because lower iron levels have been linked to increased cadmium retention. In spite of the relationship between low iron status and higher cadmium levels, subjects who took vitamins, which usually contain iron, had higher BCd and UCd levels. The researchers suggest that the vitamins may have been contaminated contaminated, v 1. made radioactive by the addition of small quantities of radioactive material. 2. made contaminated by adding infective or radiographic materials. 3. an infective surface or object. with cadmium, as has happened before with vitamin-mineral supplements used for pig feed. The researchers also compared cadmium levels in the kidneys of slaughtered pigs with the BCd and UCd of people living on the farms on which the animals were raised. Because the pigs were fed locally grown grain, their kidney cadmium levels was presumed to reflect the cadmium levels in the soil. But cadmium levels in the pigs did not predict cadmium levels in people living on the same farms. A possible explanation, the researchers say, is that much of the cereals and other foods that the subjects ate wasn't grown locally; another is that ingredients besides locally produced grain were contributing to the pigs' cadmium intake. |
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