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

AX6-93
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)
Hsiao et al. (2001)
Taiwan, PR China
1991-1998
30 Pb battery workers.
Mean serum creatinine at baseline
~ 1.0 mg/dL (based on figure; exact values not provided)
Longitudinal Analysis, 8 annual evaluations.
Generalized estimating equations used to adjust for
autocorrelation in multiple datapoints from each
participant.
Adjusted for age, gender, and, in models of change in
serum creatinine, creatinine at beginning of interval.
Mean blood Pb at baseline
~35 µg/dL (based on figure;
exact values not provided)
Mean duration of exposure
at baseline
13.1 yrs
Cross-sectional
higher blood Pb associated with lower concurrent
serum creatinine.
Longitudinal
Change in blood Pb negatively associated with
concurrent change in serum creatinine (p = 0.07).
Blood Pb at the beginning of the interval not associated
with change in serum creatinine in the following yr.
Associations may represent Pb-related hyperfiltration.
However, as noted by the authors, cumulative Pb dose
may also be a factor. Mean blood Pb declined greatly
just before renal data collection started. Therefore, the
inverse longitudinal associations could be due to
persistently elevated cumulative dose (which was
unmeasured but, as evidenced by the long half-life of
bone Pb, likely did not decline as much as blood Pb).
However, authors did not model cumulative blood Pb
or analyze effect modification by time period, age, or
exposure duration to determine if these associations
changed in a pattern consistent with hyperfiltration.
The small sample size also limits conclusions that may
be drawn from these results since a small number of
individuals may be overly influential.
Strengths = longitudinal data.
Limitations = data analysis content (Pb dose means not
reported), clarity and adjustment.