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

AX6-21
Table AX6-2.6 (cont’d). Effects of Lead on Disturbances in Behavior, Mood, and Social Conduct in Children
Reference, Study
Location, and Period Study Description Pb Measurement Findings, Interpretation
Europe
Wasserman et al.
(1994)
Yugoslavia
Australia
Burns et al. (1999)
Australia
Fergusson et al. (1993)
New Zealand
Design: Prospective longitudinal. Birth cohort
of ~300-400 infants followed since birth
residing in two towns in Kosovo, Yugoslavia,
one group near a longstanding Pb smelter and
battery manufacturing facility and another in a
relatively unexposed location 25 miles away.
379 children at 3 yrs of age were examined.
Parents were interviewed with the Achenbach
Child Behavior Checklist (CBCL). Extensive
assessment of medical and sociodemographic
covariates.
Design: Prospective longitudinal. 322 subjects
residing in and near Port Pirie, Australia and
followed since birth were re-evaluated at 11-13
yrs of age. Parents completed the Achenbach
Child Behavior Checklist. Extensive
assessment of medical and sociodemographic
characteristics.
Design: Prospective cohort. 690-891 children
ages 12 and 13 yrs from the Christchurch Child
and Health Study, New Zealand were examined.
Mothers and teachers were asked to respond to
a series of items derived from the Rutter and
Conners parental and teacher questionnaires.
Extensive assessment of sociodemographic and
medical covariates.
Maternal prenatal, umbilical cord
and serial postnatal blood Pb
Maternal blood Pb in exposed
area 19.9(SD 7.7) µg/dL,
unexposed area 5.6
(SD 2.0) µg/dL
Umbilical cord blood Pb in
exposed area 22.2
(SD 8.1) µg/dL,
unexposed area 5.5
(SD 3.3) µg/dL
Blood Pb at 2 yrs in exposed area
35.4 µg/dL, unexposed area
8.5 µg/dL
Maternal prenatal, umbilical cord
and serial postnatal blood Pb
Antenatal avg blood
Pb 10.1 (SD 3.9) µg/dL
Umbilical cord blood Pb
9.4 (SD 3.9) µg/dL
Blood Pb at 2 yrs
geometric mean 21.3
(SD 1.2) µg/dL
Tooth (dentine) Pb
Tooth Pb range 3–12 µg/g
Following covariate adjustment, concurrent blood Pb levels
were associated with increased Destructive Behaviors on the
CBCL subscale, although the variance accounted for by Pb
was small compared to sociodemographic factors. As blood
Pb increased from 10 to 20 µg/dL, subscale scores increased
by 0.5 points. The authors conclude that while statistically
significant, the contribution of Pb to social behavioral
problems in this cohort was small compared to the effects of
correlated social factors.
After adjustment for covariates, regression models revealed
that for an increase in avg lifetime blood Pb concentrations
from 10 to 30 µg/dL, the Externalizing behavior problem T
score increased by 3.5 points in boys (95% CI: 1.6, 5.4), but
only 1.8 points (95% CI: !0.1, 11.1) in girls. Internalizing
behavior problems were predicted to rise by 2.1 points (95%
CI: 0.0, 4.2) in girls by only 0.8 (95% CI: !0.9, 2.4) in boys.
Authors concluded that Pb exposure is associated with an
increase in externalizing (undercontrolled) behaviors in boys.
Statistically significant dose-effect relationships were
observed between tooth Pb levels and the
inattention/restlessness variable at each age. Authors
conclude that this evidence is consistent with the view that
mildly elevated Pb levels are associated with small but long
term deficits in attentional behaviors.