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The objective of this study was to evaluate the association between blood cadmium (Cd) and moderate-to-severe glomerular dysfunction in a Korean population using a representative sample. A cross-sectional study was used to evaluate the association between blood Cd and glomerular dysfunction. Based on the Korean National Health and Nutrition Examination Survey (2005–2008), individual blood Cd was measured in 2,992 adults, aged between 20 and 65. After adjusting for survey years, age, sociodemographic factors, and health behaviors, the odds ratio for moderate-to-severe glomerular dysfunction (

The role of biological monitoring (BM) in the prevention of exposure to toxic metals has currently acquired considerable importance. However, in the near future the usefulness of BM in occupational medicine could be reduced by the fact that exposure to toxic substances will progressively decrease and consequently problems of comprehension will occur. BM can maintain its importance in the prevention field if sensitivity and specificity of the biological indicators (BI) are increased and if this activity is specifically directed towards groups of subjects. To achieve this last goal, one of the problems which must be solved is the identification of "reference values" (RV) which define the BI levels in the general population not occupationally or environmentally exposed to the toxic substance under study. It is necessary to "refer" to these values in order to compare the data obtained in a population which is presumed to be exposed. In this presentation, the example of blood cadmium is used in order to discuss the criteria required to identify RV. Herein the data of a personal case list are reported, particularly the variables which must be considered when selecting subjects to form "reference groups". Conversely, the possibility of obtaining RV through meta-analysis studies, pooling the results published in international literature, are evaluated.

Biological monitoring, i.e. using individual measures of exposure such as cadmium in blood, is supposed to reflect the real dose better than the more commonly used external measures such as air-cadmium. In order to investigate this, cumulative cadmium doses were estimated individually for 440 workers in a battery factory. Cumulative air-cadmium dose as well as two different cumulative blood-cadmium doses were computed for each study individual. Forty workers had evidence of tubular proteinuria and a clear dose-response relationship was found for each of the dose estimates. Our results suggest that cumulative blood-cadmium is a more sensitive indicator of cadmium-induced renal dysfunction than cumulative air-cadmium.

The individual cumulative cadmium dose was estimated for 44 smelter workers in a cadmium-copper alloy plant. Two different principles were used: cumulative respiratory dose and cumulative average annual blood-cadmium dose. Out of eight workers with a cumulative respiratory dose exceeding 500 mg Cd . h/m3, two of them (25%) had signs of a cadmium-induced renal dysfunction. These two men were the only workers that had a cumulative average annual blood cadmium dose exceeding 200 micrograms Cd . year/l. Our results suggest that measurements of cadmium in the blood can be used as an indicator of the cadmium exposure of each individual and that, in order to prevent renal dysfunction, the average blood-cadmium concentration should not exceed 10 micrograms Cd/l over periods of many years (decades).

Between 1982 and 1986 several surveys were carried out to determine the levels of lead and cadmium in blood, urine, and shed deciduous teeth (incisors only) of children living in rural, suburban, urban, and industrial areas of North-West Germany. Blood lead (PbB) and blood cadmium (CdB) were measured in about 4000 children. In rural, suburban and urban areas the median PbB levels vary between 5.5 and 7 micrograms/dl, with 98th percentiles varying between 10 and 13 micrograms/dl. The median CdB levels are between 0.1 and 0.2 microgram/dl, with 95th percentiles between 0.3 and 0.4 microgram/l. Children from urban areas have significantly higher PbB levels than children from rural and suburban areas. Regarding CdB no differences could be detected. Children living in areas around lead and zinc smelters, particularly those living very close to the smelters, have substantially increased PbB and CdB levels. Children from lead worker families also have substantially increased PbB and CdB levels. The lead levels in shed milk teeth (PbT) were determined in about 3000 children. In rural, suburban and urban areas the median PbT levels are between 2 and 3 micrograms/g, with 95th percentiles between 4 and 7 micrograms/g. Children from urban areas have significantly higher PbT levels than children from rural and suburban areas. The highest PbT levels (on a group basis) are in children from nonferrous smelter areas. The median levels of lead in urine (PbU) are between 6 and 10 micrograms/g creatinine, with 95th percentiles between 20 and 30 micrograms/g creatinine. Children from polluted areas have higher PbU levels than children from less polluted areas. The median levels of cadmium in urine (CdU) are in the order of 0.1 microgram/g creatinine, with 95th percentiles being in the range of 0.5 and 1.0 microgram/g creatinine. Girls have higher CdU levels than boys. There are no differences between groups of children from different areas. Children from lead worker families have higher PbU and CdU levels than otherwise comparable children. The results of the present studies indicate a further decrease of PbB in children from North-West Germany since the CEC blood lead campaigns carried out in 1979 and 1981. The decrease of lead exposure also seems to be reflected by a decrease of tooth lead levels.