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.
Boujemaa
W
W
Unit of Industrial Toxicology and Occupational Medicine, Catholic University of Louvain, Faculty of Medicine, Brussels, Belgium.
Lauwerys
R
R
Bernard
A
A
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