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

AX6-67
Table AX6-3.9 (cont’d). Other Neurological Outcomes Associated with Lead Exposure in Adults
Reference, Study
Location, and Period Study Description Pb Measurement Findings, Interpretation
United States (cont’d)
Kamel et al. (2003)
Massachusetts
Armon et al. (1991)
Minnesota
Europe
Chancellor et al.
(1993)
Scotland
1990-1991
Gunnarsson et al.
(1992)
Sweden
1990
As above, the same data was used to
determine the associations of ALS with
polymorphism in ALAD and the vitamin D
receptor (VDR) and the influence of
genotype.
A case-control design with 47 ALS patients,
mean age 61 with involvement of upper and
lower motor neurons and 201 controls, mean
age 62. For the Pb exposure analysis 45 male
matched pairs were examined.
A case-control design 103 ALS patients from
the Scottish Motor Neuron Disease Register
and matched community controls.
Differences in potential occupational
exposures were determined between cases
and controls.
A case-control study of 92 cases of MND
and 372 controls. MND included ALS,
progressive bulbar paresis (PBP), and
progressive muscular atrophy (PMA).
Relation of MND to risk factors including
occupational exposure examined.
Same as above The ALAD2 allele was associated with a 2-fold increase risk of ALS
after adjustment for the covariates, age, sex, region, education and
physical activity adjusted (OR = 1.9 [95% CI: 0.60, 6.3]).
Additionally adjusting for blood Pb strengthened the association of
ALAD2 and ALS risk adjusted (OR = 3.6 [95% CI: 0.9, 15]). This
was not found for bone Pb or occupational history of Pb exposure
(patella-adjusted OR = 2.1 [95% CI: 0.61, 6.9]; tibial-adjusted (OR =
2.2 [95% CI: 0.66, 7.3]; occupational history-adjusted
(OR = 2.4 [95% CI: 0.67, 8.7]). VDR was not associated with Pb or
ALS risk.
Lifetime exposure to Pb of
200 hrs or more (yrs on job x
hrs spent per wk)
Exposure to Pb obtained by
lifetime employment history
from Office of Population and
Censuses and Surveys.
Physician’s record review and
direct interview questionnaire.
Exposure information
obtained by self-administered
questionnaire.
Of 13 discordant pairs for Pb exposure, 11 were in ALS patient. The
relative risk was 5.5 (95% CI: 1.44, 21.0). A dose-response was
weakened by 3 controls with highest lifetime exposure. Men with
ALS worked more often at blue collar jobs and significantly more
time welding (p < 0.01). These results expanded a prior pilot study
that found a higher incidence of heavy metal exposure in ALS cases.
Odds ratio for manual labor in ALS patients was 2.6 (95% CI: 1.1,
6.3). Occupational exposure to Pb was more common in ALS
patients (OR = 5.7 [95% CI: 1.6, 30]).
Exposure to heavy metals primarily from welding had an increased
Mantel-Haenszel OR = 3.7 [95% CI: 1.1, 13.0].