The World Health Organization study on health effects of exposure to cadmium: morbidity studies.

Studies according to the protocol of the WHO Regional Office for Europe were performed in Germany, the Netherlands and Belgium. Pilot studies were performed in Czechoslovakia, Hungary and Poland. The results of the Belgian study are described elsewhere; some striking results of the other studies are reported here. The highest levels of cadmium in blood (Cd-B) were reported in a cadmium-polluted area in Hungary, the lowest in a non-polluted urban area. In Poland, levels were enhanced in polluted and non-polluted areas. The highest levels of cadmium in urine (Cd-U) were found in Hungary, the lowest in the Netherlands. In nearly all the studies significant increases in both Cd-B and Cd-U were found in cadmium-polluted areas. The picture is less clear with regard to the biological effect parameters. The renal parameters were sometimes significantly enhanced for the polluted areas, but sometimes the opposite was reported. Because of the many confounding variables, stratification at least by smoking behaviour, sex and age is necessary if firm conclusions are to be reached. A better approach, however, is to use multivariate regression analysis. This technique allowed the calculation of the relation between Cd-U and age in the German and Dutch studies, and between Cd-U and age in the German and Dutch studies, and between Cd-U and NAG, AAP, Alb-U and Creat-S levels.