Background: The clinical relevance of renal effects of cadmium in people exposed in the environment remains uncertain. This study examined the evolution of renal effects observed in a population exposed to cadmium in the environment.
Methods: 208 men and 385 women surveyed in 1985-89 (Cadmium in Belgium study [Cadmibel]; baseline) were re-examined on average 5 years later (Public health and environmental exposure to cadmium study [PheeCad]; follow-up). Urinary and blood cadmium and markers of renal tubular dysfunction and glomerular effects were measured. The association between cadmium body burden and renal factors was examined by multivariate logistic and linear regression.
Findings: In men, mean urinary cadmium excretion and blood cadmium concentration measured at follow-up were 7.5 nmol/24 h (SD 1.9) and 6.1 nmol/L (2.2), reductions of 16% and 35% from baseline, respectively. In women, the corresponding values were 7.6 nmol/24 h (1.9) and 7.8 nmol/L (2.1), reductions of 14% and 28% from baseline. No indication of progressive renal damage was found and the overall results suggest that the effects of low environmental exposure to cadmium on the kidney are weak, stable, or reversible.
Interpretation: Subclinical renal effects that have been reported in Belgium in patients with increased cadmium body burden are not associated with progressive renal dysfunction and most likely represent non-adverse manifestations.