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

AX6-45
Table AX6-3.3 (cont’d). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period Study Description Pb Measurement Findings, Interpretation
Asia (cont’d)
Schwartz et al. (2005)
South Korea
1997-2001
Longitudinal decline in neurobehavioral
performance examined in 576 of the above
group of Pb exposed workers who completed
3 visits at one yr intervals.
Mean age at baseline was 41 (9.5) yrs and
job duration 9 (6.3) yrs and 76% were men.
Compared to non-completers Pb workers
who completed 3 visits were 3.3 yrs older,
baseline mean blood Pb was 2.0µg/dL lower,
on the job 1.6 yrs longer, 24% women vs.
10% of noncompleters, and usually had less
than high school education. Models
examined short-term vs. long-term effects.
Final model had current blood Pb, tibia bone
Pb and longitudinal blood Pb and covariates.
Baseline mean (SD) blood
Pb 31 (14.2) µg/dL
Mean (SD) tibia
Pb 38 (43) µg/g
Blood Pb from baseline correlated with those from visit 2 and 3 and
baseline tibial Pb correlated with that measured at visit 2. Crosssectional
associations of blood Pb or short-term change occurred with
Trails A (∃ = !0.0020 [95% CI: !0.0040, !0.0001]) and B
(∃ = !0.0037 [95% CI: !0.0057, !0.0017]), Digit Symbol (∃ = !0.0697
[95% CI: !0.1375, !0.0019]) , Purdue Pegboard
(dominant ∃ = !0.0131 [95% CI: !0.0231, !0.0031]; non-dominant
∃ = !0.0161 (95% CI: !0.0267, !0.0055); both (∃ = !0.0163, [95% CI:
!0.0259, !0.0067]; assembly (∃ = !0.0536 [95% CI: !0.0897,
!0.0175]), and Pursuit Aiming (# correct ∃ = 0.1526, [95% CI:
!0.2631, !0.0421]) after covariates. However, longitudinal blood Pb
was only associated with poorer performance on Purdue Pegboard
(non-dominant ∃ = !0.0086 [95% CI: !0.0157, !0.0015]; both
(∃ = !0.0063 [95% CI: !0.0122, 0.0004]; assembly (∃ = !0.0289 [95%
CI: !0.0532, !0.0046]). Historical tibial bone Pb was associated with
digit symbol (∃ = !0.0067 [95% CI: !0.0120, 0.0014]) and Purdue
Pegboard (dominant ∃ = !0.0012, [95% CI: !0.0024, !0.0001]).
Magnitude of Pb associations was expressed as the number of yrs of
increased age at baseline that was equivalent to an increase of Pb from
the 25th to 75th percentile. At baseline, these Pb associations were
equivalent to 3.8 yrs of age for cross-sectional blood Pb, 0.9 yrs of
age for historical tibial Pb and 4.8 yrs of age for longitudinal blood
Pb. Analyses showed decline in performance over time related to
tibia Pb.