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Advisory Committee on Health Effects of Endocrine Disruptors
The Supplement II to the Intermediary Report
1.4.2.2_7 |
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3. Other substances
1) Cohort studies
None.
2) Case-control studies
None.
3) Synchronic studies
Nagayama et al. (2001) studied effects on the thyroid hormones
and immune response system of polychlorodibenzo-p-dioxin (PCDD),
polychlorodibenzofurane (PCDF) and coplanar polychlorinated
biphenyl (co-PCB) for 16 yusho patients about 30 years after the
prevalence.
Blood samples were collected in 1996-97 from 16 patients (3 men
and 13 women, 28-75 years of age) and 83 subjects as the
control. Serum T3, T4 and TSH levels were measured, and blood
lymphocyte subset, autoantibody and immunoglobulin levels were
determined by indirect immunoluminescence and latex photometric
immunoassay (LPIA).
The blood TEQ levels of the patients were 27.8-1048.5 pg/g fat
(median 222.4 pg/g fat) or about 7 times higher than in the
control. Serum T3, T4, free T4 and TSH were normal in all the
samples except one which showed a serum T4 concentration of 15.5
μg/dl, compared with the normal range 4.6-12.6 μg/dl.
Immunoglobulins (IgA, IgG, IgM), autoantibodies (antinuclear
antibody, rheumatoid factor, IE factor) and lymphocyte subsets
were unaffected, while the positivity rate for rheumatoid factor
was higher in the group with high blood TEQs.
Pavuk et al. (2003) studied the association of
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in serum with health
conditions by comparing veterans who were exposed to TCDD-contaminated
exfoliating agent used in Operation Ranch Hand (exposed group)
in 1962-71 and those who did not participate in the operation
(control group).
Thyroxine (total T4), thyroid stimulating hormone (TSH),
triiodothyronine uptake (T3 % uptake), free thiroxine index (FTI)
and thyroid diseases were analyzed against serum TCDD
concentration. Data were obtained from 1009 cases in the exposed
group and 1429 cases in the control who participated in any of
the examinations conducted in 1982, 1985, 1987, 1992 and 1997.
The subjects were classified into four groups: Comparison, Ranch
Hand Background, Ranch Hand Low Elevated and Ranch Hand High
Elevated.
Average serum TCDD levels were 4.6 ppt in Comparison, 5.8 ppt in
Background, 15.6 ppt in Low Elevated, and 69.4 ppt in High
Elevated. Cross-sectional analyses found statistically
significantly increased TSH levels at the 1985 and 1987
examinations in the High Elevated group and a significant
increasing trend across the three Ranch Hand groups in 1982,
1985, 1987 and 1992. A repeated-measures analysis found
significantly increased TSH means in the High Elevated group. No
significant relation was found between the occurrence of thyroid
disease and TCDD level.
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