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

AX6-43
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
Europe (cont’d)
Winker et al. (2005)
Austria
Winker et al. (2006)
Austria
48 workers formerly Pb-exposed, mean
duration since last exposure 5 (3.5) yrs, and
mean age 40 (8.8) yrs were matched with 48
controls for age, verbal intelligence, yrs of
education and number of alcoholic drinks.
Group differences and dose-response
relationship were explored.
The same 48 workers formerly Pb-exposed
described above were compared to the
47 exposed workers described by Barth et al.
(2002). Both groups were comparable for
age and verbal intelligence. Group
differences and differences by duration of
exposure and exposure absence were
evaluated.
Formerly Pb-exposed
Mean (SD, range) blood Pb
5.4 (2.7, 1.6-14.5) µg/dL
Mean (SD) IBL 4153.3
(36930.3) µg·yr/dL
Controls
Mean (SD, range) blood Pb
4.7 (2.5, 1.6-12.6) µg/dL
Exposed workers
Mean (SD, range) blood Pb
31 (11.2, 10.6-62.1) µg/dL
Mean (SD) IBL 4613
(4187.6) µg·yr/dL
Formerly Pb-exposed
Mean (SD, range) blood Pb
5.4 (2.7, 1.6-14.5) µg/dL
Mean (SD) IBL 4153.3
(36930.3) µg·yr/dL
No significant differences on neurobehavioral battery were present
when groups compared by t-tests for paired samples. When the
groups were combined, partial correlation adjusting for age found
significant negative correlation between blood Pb and Block Design,
(r = −0.28, p < 0.01) Visual Recognition (r = −0.21, p < 0.05) and
Digit Symbol Substitution (r = −0.26, p < 0.01). The authors
conclude that the cognitive deficits associated with low-level Pb
exposure are reversible. However there appears to be a residual effect
primarily from those with the highest past Pb exposure.
Mann-Whitney test found significantly better performance in the
formerly Pb-exposed workers for Block Design (p = 0.005) and
Wisconsin Card Sorting Test (categories p = 0.0005, total errors
p = 0.005, perseverations p = 0.0095 and loss of sorting principle
p = 0.02). To further examine the reduction of cognitive impairment
with absence of exposure, workers were stratified by duration of
exposure and exposure absence – short exposure and long absence;
long exposure and long absence; short exposure and short/no absence
and long exposure and short/no absence. Linear contrasts for Block
Design (p = 0.003) and Wisconsin Card Sorting Test (categoriesp
< 0.001, total errors p = 0.001, perseverations p = 0.019 and loss of
sorting principle p = 0.030) were highly significant in the
hypothesized direction. Results were believed to support reversibility
of cognitive deficits related to occupational Pb exposure.