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Lead‐induced nephropathy: Relationship between various biological exposure indices and early markers of nephrotoxicity
Author(s) -
Chia K. S.,
Jeyaratnam J.,
Lee James,
Tan Cynthia,
Ong H. Y.,
Ong C. N.,
Lee Evan
Publication year - 1995
Publication title -
american journal of industrial medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 104
eISSN - 1097-0274
pISSN - 0271-3586
DOI - 10.1002/ajim.4700270612
Subject(s) - medicine , nephrotoxicity , nephropathy , lead exposure , lead (geology) , toxicity , occupational exposure , toxicology , endocrinology , environmental health , diabetes mellitus , biology , cats , geomorphology , geology
Lead nephropathy in adults is silent and insidious, characterized by the absence of proteinuria in its early phase. Of the early markers of nephrotoxicity, urinary N‐acetyl‐β‐D‐glucosaminidase (NAG) appears to be the only one that is elevated in early lead nephropathy. However, the elevation in urinary NAG activity may be a response to a sharp increase in renal burden of lead. Its usefulness as a marker of chronic lead nephropathy is thus in doubt. There is a need, then, to identify a reliable early biological indicator of lead‐induced kidney damage. Furthermore, there is also a need to identify suitable markers of chronic exposure to describe meaningful dose‐response and dose‐effect relationships. Traditionally, blood lead (PbB) was used, but the current blood lead level (PbB rec ) is more an indicator of recent exposure. Time‐integrated blood lead indices (PbB int ) derived from repeated serial PbB measurements can be used as indices of chronic exposure. In 128 lead‐exposed workers, the PbB int was the most important exposure variable in describing the variability in urinary α 1 ‐microglobulin (Uα 1 m), urinary β 2 ‐microglobulin (Uβ 2 m), and urinary retinol binding protein (URBP). Uα 1 m was the only marker that was significantly higher in the exposed group, with a good dose‐response and dose‐effect relationship with PbB int . The lack of dose‐response and dose‐effect relationships in other studies may be due to inappropriate exposure markers as well as less sensitive response markers. PbB int has a better correlation than PbB rec . Furthermore, Uα1m may be the most sensitive of the markers because of its higher molecular weight.