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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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[Results]
1. Organochlorine compounds
Organochlorine compounds were addressed in relation to infantile
nerve development in 22 reports published before Dec. 31, 2000.
An additional 14 reports appeared by Oct. 31, 2004, which
consisted of 11 follow-up studies of previously reported
affairs, and 3 studies of newly established cohorts.
1) Cohort studies
The subjects in the cohort studies can be classified into (i)
populations severely exposed due to accidents and those from the
polluted areas, (ii) pregnant women who took fish from lakes
where pollutants are accumulated, and (iii) general populations.
(i) Severely exposed populations and polluted areas
Harada et al. (1976) observed 13 children victimized in yusho
incidence in Kyushu in 1968 over 7 years, and found deficiency
in emotional expression, low muscle tension and low IQ.
The yusho incidence in Taiwan in 1978-79 was studied by Rogan et
al. (1988) and Chen et al. (1992, 1994). Children born by
mothers affected by the disease showed delayed growth, delayed
development of motor function, and low cognition ability in
follow-up from 2 to 12 years of age. Lai et al. (2001) also
followed up 118 yusho victims (exposed group), 2-12 years of
age, and a control group consisting of 118 children from the
same region, and suggest long-term deleterious effects of
prenatal exposure to PCBs and their derivatives on the cognitive
development of children.
Lai et al. (2002) evaluated the behavior of these children using
Wechsler intelligence scale, Achenbach's Child Behavior
Checklist (CBCL) and Rutter's child behavior scale A. The
exposed group showed 3 points lower IQ score (p = 0.05) and 3
points higher CBCL score (p = 0.002). No sex difference in the
effect was observed. Aging improved Rutter's scale only, of
which the difference between the exposed and control groups
disappeared eventually. The researchers concluded that prenatal
PCB exposure induces persistent problems in cognition and
behavior of children, which are partially cured by aging.
Ribas-Fito et al. (2003) studied in 1997-99 the nerve
development of 92 one-year children living near an
electrochemical plant in Spain in relation to exposure to
organochlorines and breast feeding. Nerve development was
evaluated by BSID-II (Bailey Scale II of Infant Development) and
Griffiths Scale at 13 months of age. Exposure was estimated by
cord serum levels of hexachlorobenzene (HCB),
dichlorodiphenyldichloroethylene (p,p'-DDE) and PCBs (28, 52,
101, 118, 138, 153). Analysis revealed correlation of p,p'-DDE
level with delay in mental and motor development at 13 months of
age, but no association was noticed for HCB. Babies with
relatively high p,p'-DDE levels and shorter period of breast
feeding showed lower scores in intellectual and motor
development, suggesting that a prolonged breast feeding mitigate
adverse effects of chemical exposure.
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