Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

AX6-95
Table AX6-4.2 (cont’d). Renal Effects of Lead in the Occupational Population
Reference, Study
Location, and
Period Study Description Pb Measurement Findings, Interpretation
Asia (cont’d)
Kumar and
Krishnaswamy
(1995)
India
Study date not
provided
Lim et al. (2001)
Singapore
1999
Blood Pb levels every
6 mos from 1982 to
1999
22 auto mechanics volunteers.
27 male control workers (from Institute performing study).
Renal outcomes = serum creatinine, 4 h creatinine
clearance and urinary NAG and ∃-2 microglobulin.
Renal disease, diabetes, HTN and occupational exposures
excluded in controls, possibly excluded in workers.
55 male Pb workers.
Workers followed since 1982, many of same workers as in
Chia et al. (1995b).
Renal outcomes = 4 h creatinine clearance and urinary
albumin, RBP, α1 microglobulin, ∃ 2 microglobulin, NAG,
NAG-A, and NAG-B.
Exclusionary criteria included diabetes, HTN, recent
ingestion of analgesics, antipyretics, or antibiotics, and
thalassemia; 24 participants of the original 80 were
excluded as a result. One female also excluded.
Blood Pb range
24.3-62.4 µg/dL (exposed)
19.4-30.6 µg/dL (controls)
Mean current blood Pb
24.1 µg/dL
Cumulative blood index
880.6 µg Η yrs/dL (geometric
mean)
Number of times blood Pb
exceeded 40 µg/dL
1.9 (geometric mean)
Urinary NAG and ∃ 2 microglobulin levels were
significantly higher in exposed compared to controls.
However, only NAG was significantly correlated with
blood Pb (r = 0.58, p < 0.01).
Limitations = study size and lack of adjustment in
analysis, values for 4 h creatinine clearance in
abnormal low range in both exposed and controls.
In separate models, after adjustment for age and
smoking, higher categorical cumulative blood index
and number of times blood Pb exceeded 40 µg/dL were
associated with lower creatinine clearance (P < 0.001).
After adjustment, higher number of times blood Pb
exceeded 40 µg/dL was associated with higher urinary
albumin, α 1 microglobulin, RBP, NAG, and NAG-B.
Similarly, cumulative blood index was associated with
higher urinary albumin, α 1 microglobulin, RBP, and ∃ 2
microglobulin.
No associations between recent blood Pb and any of
the renal outcomes was observed.
Analysis of covariance was used to adjust for smoking
and age.
Limitation = statistical analysis - lack of adjustment,
small sample size, potential for healthy worker bias.