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Advisory Committee on Health Effects of Endocrine Disruptors
The Supplement II to the Intermediary Report
1.4.2.2_10 |
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In a prospective cohort study on 171 healthy mother-child pairs
in Düsseldorf, the cognitive and nerve development of children
were evaluated by the BISD and Fagan tests at 7 months of age (Walkowiak
et al., 1998). Follow-up was made by tests with BSID-II and
Kaufman scale at 7, 18, 30 and 42 months of age. In addition,
the home environment was evaluated using the HOME (Home
Observation for Measurement of Environment) scale when the
children were 18 months of age (Walkowiak et al., 2002). These
data were used in an overall study of effects of PCB exposure on
the intellectual and motor development of infants. Pre- and
perinatal PCB exposure was evaluated by determining PCB-138, 153
and 180 in the cord blood of newborns and in breast milk.
Significant inverse correlation was observed between milk PCB
and baby's intellectual and motion development at the 30th and
42th month. Data for the 42th month indicate positive effects of
good home environment on the child's development after the 30th
month, while effects of PCB exposure via breast milk were also
seen. It was thus suggested that prenatal PCB exposure at a
background level retards mental and motor development of babies
until the 42th month, but this effect is countered by favorable
home environment which promotes the development.
Daniels et al. evaluated nerve development of 8 months-old
babies by BSID test in a multicenter study on 1207 mother-child
pairs from 12 regions in the U.S. conducted in 1959-65. As the
measure for exposure, mothers' blood samples collected at every
8th week during gestation and the 6th week after delivery were
analyzed for the total PCB including 11 homologues (PCB28, 52,
74, 105, 118, 138, 153, 170, 180, 194, 203). No correlation was
found between mothers' serum PCB and children's mental and
motion development (MDI and PDI scores) (Daniels et al., 2003).
The lack of correlation between PCB exposure and MDI score as
observed in this study was in agreement with findings of many
precedent studies.
The 12 research institutes were not unanimous on the association
of PCB exposure with motion development (PDI scores) in spite of
standardization of timing of examination and procedure of PCB
determination, presumably because of influences of uncontrolled
factors such as food or exposure to mercury and lead.
Riva et al. (2004) studied association of colostrum PCB level
and visual function at the 12th month of 25 infants born in
Milan and its suburbs and breast-fed at least up to the 4th
month. PCB 105, 118, 138, 153, 156 and 180, as well as DDT and
DDE, in the colostrum collected two days after delivery and
breast milk collected one and three months after delivery were
analyzed. Long-chain polyunsaturated fatty acids (LC-PUFAs)
C18:2 n-6, C18:3 n-3, C20:4 n-6. C20:5 n-3 and C22:6 n-3 in the
plasma of all the infants were determined within the first 3
days after the birth. The colostral PCB as well as LC-PUFAs in
plasma were considered to mirror perinatal supply. Visual
function was evaluated by P100 latency of visually evoked
potential (VEP) test at 12 months of age. Analysis found that
P100 latency was correlated with DDT level (r = 0.513) and PCB
level (r = 0.504) at a visual angle of 60 min, and with
colostral levels of DDT, DDE and all the PCBs except PCB 105 (r
= 0.401-0.618) at 15 min. Infant plasma levels of C22:6 n-3 were
inversely associated with P100 wave latency at 60 min (r =
-0.418) and at 1 Hz-2 J (r = -0.466). After controlling for
C22:6 n-3, the partial correlation coefficient of P100 wave
latency at 15 min to the colostral level of PCB 180 was 0.403 (p
= 0.07). A weak relation was thus found between impaired visual
function at 12 months of age of healthy infants and the levels
of PCBs, DDT and DDE in colostrum. The effect of impairment was
no longer evident after controlling for the plasma level of LC-PUFAs
as found in the infant a few days after birth.
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