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

AX6-33
Table AX6-3.2. Symptoms Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period Study Description Pb Measurement Findings, Interpretation
Canada
Lindgren et al. (1999)
Canada
Holness et al. (1988)
Canada
Europe
Lucchini et al. (2000)
Italy
Smelter workers (n = 467) with a mean age
of 40 yrs completed the Profile of Mood
Scale. Factor structure of POMS validated in
this occupational population. Regression
analysis determined association with Pb
exposure.
47 demolition workers with acute Pb
intoxication - Phase 1 - were followed with
blood Pb and symptoms during engineering
modifications to control exposure –
Phases 2-4. Workers stratified by blood Pb
and symptom frequency was analyzed.
66 workers in Pb manufacturing, mean age
40 (8.7) yrs and 86 controls mean age 43
(8.8) yrs were administered a questionnaire
with neuropsychological (14 items), sensorymotor
(3 items), memory (4 items) and
extrapyramidal (8 items), 10 Parkinson
symptoms and the Mood Scale. Group
comparisons and linear regression examined
relationship of symptoms and Pb exposure.
Mean (SD, range) blood Pb
28 (8.5, 4-62) µg/dL
Mean (SD, range) IBL 711
(415.5, 1-1537) µg·yr/dL
Phase I - Mean blood Pb
59 µg/dL
Phase 2 - Mean blood Pb
30 µg/dL
Phase 3 - Mean blood Pb
19 µg/dL
Phase 4 - Mean blood Pb
17 µg/dL
Pb workers
Mean (SD, range) blood Pb
27 (11.0, 6-61) µg/dL
Mean (SD, range) TWA 32
(14.1, 6-61) µg/dL
Mean (SD, range) IBL 410
(360.8, 8-1315) µg·yr/dL
Controls
Mean (SD, range) blood Pb
8 (4.5, 2-21) µg/dL
Factor analysis found one factor labeled “general distress” composed
of POMS subscales anger, confusion, depression, fatigue and tension
and a second factor labeled ‘psychological adjustment.’ IBL was
significantly associated with ‘general distress’ after adjustment for the
covariates (�∃ = 0.28 [SE 1.51 Η 10 !4 ], p = 0.01) while there was no
relation with blood Pb. The factor structure of POMS originally
validated in a clinical population had six mood subscales however the
factor structure in this occupational population was found to have
only two subscales.
Below blood Pb 70 µg/dL. Of interest, at beginning of Phase 4 when
mean blood Pb was 13 µg/dL, no symptoms were reported. At the
end of Phase 4, mean blood Pb was 17 µg/dL and one worker
complained of fatigue.
Pb exposed worker reported confusion, somnolence, abnormal
fatigue, irritability, and muscular pain more frequently (p < 0.04).
There were no group differences for the parkinsonism symptoms or
Mood Scale. Linear regression combing exposed and control group
found neurological symptoms significantly associated with blood Pb
r = 0.22, p = 0.006). Neuropsychological symptoms were
significantly higher in the High-IBL compared to the Low-IBL group.
The estimated threshold for a significant increase (prevalence of 5%)
of a high score for neurological symptoms was at a blood Pb of
12 µg/dL.