Early indicators of renal dysfunction in silicotic workers.
OBJECTIVE
The aim of this study was to determine whether silicosis is associated with renal alterations detectable in urinary or blood-borne indicators of nephrotoxicity.


METHODS
The study used a cross-sectional design. The subjects comprised 116 male workers who had been exposed to silica for at least two years and had been diagnosed as having silicosis and 61 age-matched referents. The considered outcome measures were the concentrations of beta, -microglobulin and creatine in serum and the urinary excretion of albumin, retinol-binding protein, and beta-N-acetyl-D-glucosaminidase.


RESULTS
Compared with the referents, the silicotic subjects excreted, on the average, slightly higher amounts of albumin, retinol-binding protein, and beta-N-acetyl-D-glucosaminidase. This increase did not correlate with the duration of exposure or the stage of silicosis and was not associated with an elevation in serum creatinine. The concentration of beta2-microglobulin in the serum of silicotic subjects showed a tendency to rise that became significant in the subgroup with pseudotumoral opacities. This effect, which did not correlate with markers of nephrotoxicity, is however more likely the consequence of silicosis-associated inflammatory reactions than of decreased renal filtration.


CONCLUSIONS
The present study confirms that silicosis is associated with some infraclinical renal alterations. However, in the absence of a relationship with length of exposure or severity of silicosis, the implication of silica in their causation needs to be examined further.
Unit of Industrial Toxicology and Occupational Medicine, Catholic University of Louvain, Faculty of Medicine, Brussels, Belgium.
W
W
Boujemaa
R
R
Lauwerys
A
A
Bernard
D000118:Acetylglucosaminidase / Q000097:blood / Q000652:urine; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000419:Albuminuria; D016022:Case-Control Studies; D015984:Causality; D003404:Creatinine / Q000097:blood / Q000652:urine; D003430:Cross-Sectional Studies; D006801:Humans; D007674:Kidney Diseases / Q000150:complications / Q000175:diagnosis* / Q000652:urine; D008297:Male; D008875:Middle Aged; D012177:Retinol-Binding Proteins / Q000652:urine; D012720:Severity of Illness Index; D012829:Silicosis / Q000150:complications* / Q000652:urine; D013997:Time Factors; D001613:beta 2-Microglobulin / Q000652:urine
D012177:Retinol-Binding Proteins; D001613:beta 2-Microglobulin; D003404:Creatinine; D000118:Acetylglucosaminidase