Dose-response relations between urinary cadmium and tubular proteinuria in cadmium-exposed workers.
Cadmium in urine reflects the body burden in cadmium-exposed individuals. Urinary beta 2-microglobulin is frequently used as a marker of tubular proteinuria with an arbitrarily chosen value (34 micrograms/mmole creatinine) as the cut-off limit. Both this cut-off level and a lower limit (25 micrograms/mmole creatinine) were used in a study of the relationship between urinary cadmium and beta 2-microglobulin in 561 cadmium-exposed battery workers. There was a clear dose-response relation between the urinary cadmium level and the prevalence of tubular proteinuria ranging from 0.8% in the lowest exposure group, excreting less than 1 nmole cadmium/mmole creatinine, to 46.4% (50.0 for the lower cut-off level) in the highest exposure group with a mean urinary cadmium of 15 nmole/mmole creatinine. The relation between urinary cadmium and tubular proteinuria was also assessed using probit analysis. There was a 10% response at a urinary cadmium of 3 nmole/mmole creatinine. The impact of age on the dose-response relation was explored in two age groups with the cut-off point at 60 years of age, showing a 10% prevalence of tubular proteinuria at urinary cadmium levels of 1.5 nmole/mmole creatinine in this older age group and 5.0 nmole/mmole creatinine in the category under 60 years of age. The study thus indicates that the present health-based limit (10 nmole/mmole creatinine) proposed by the World Health Organization (WHO) is too high and it is suggested that a new limit should be set to 3 nmole/mmole creatinine.
Järup
L
L
Department of Occupational Medicine, Karolinska Institute, Huddinge University Hospital, Sweden.
Elinder
C G
CG
D000368:Aged; D002104:Cadmium / Q000009:adverse effects / Q000378:metabolism* / Q000652:urine; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007677:Kidney Function Tests; D007684:Kidney Tubules / Q000378:metabolism*; D008297:Male; D008669:Metallurgy; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D011507:Proteinuria / Q000139:chemically induced* / Q000652:urine
D002104:Cadmium