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Section 4: Epidemiological survey of exposure
4.1. Exposure of living bodies
[Results]
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Concentrations of the following substances in biological
samples (blood, urine, hair, etc.) were determined: bisphenol A,
chlorobenzenes, p-hydroxybenzoates, phthalates, benzo[a]pyrene,
PCBs, dioxins, chlordane, organotin compounds, 4-nonylphenol,
halogenated hydrocarbon pesticides, organophosphate pesticides,
organofluorine compounds, phytoestrogens, heavy metals, and
volatile organic compounds. (Different substances were studied
by different researchers and in different samples.) All of these
substances except chlordane were found in at least one of the
samples, suggesting exposure in the environment.
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Metabolic studies revealed that bisphenol A in blood
disappears quickly, and that phthalates are converted to mono-
or diesters.
[Future tasks]
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Continuing studies of exposure to suspected endocrine
disruptors through mother by analyses of samples from different
positions of a single mother, including cord blood
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Studying the effects, metabolism and detoxification of the
body burden of those substances
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Monitoring the environmental background in parallel to the
analyses of biological samples for evaluation of exposure.
4.2. Epidemiology
[Results]
Literature on epidemiological studies was reviewed.
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Epidemiological reports exist on the relationship of
organochlorine compounds with the incidence of breast, ovary,
prostate, testis, and thyroid cancer, but they do not provide
sufficient evidence to establish the correlation.
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Some report suggest effects of exposure to high
concentrations of PCB on the thyroid gland, but their
reliability is questionable. No credible findings have been
obtained on the effects of exposure to normal concentration
levels of organochlorine compounds including PCBs.
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A significant increase of the risk by diethylstilbestrol
(DES) of hypostadias was shown by a cohort study and of
cryptorchid by an interventional study. Other effects on organ
formation by DES are also reported but without sufficient
evidence for establishing the correlation. Few epidemiologic
studies were found on other chemical substances.
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Cohort studies on the effects of organochlorine compounds on
the infant nerve development were reported for several areas.
They are, however, not uniform in evaluation criteria for
exposure, nerve development, and other influencing factors, as
well as study periods, thus failing to provide sufficient
evidence for the correlation.
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Several papers report decreases in sperm count in groups
exposed to high concentration of chemical agents, which were,
however, unable to establish the effect of endocrine disruptors
because the possibility of testis toxicity was not excluded.
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As for the newly added review of effects on the immune
system, the reports found were incongruent: PCB was reported in
a report to increase the allergy risk of adults by exposure to
high concentrations, while another report says that exposure of
fetuses or infants to the environmental level of PCB decreases
the allergy risk.
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Epidemiologic studies on the Japanese are still very scanty.
[Future tasks]
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Establishing subject groups representative of the Japanese
and conduct monitoring for:
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exposure to suspected endocrine disruptors, and
- diseases possibly caused by endocrine disruptors
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Conducting epidemiologic studies (collection and use of
biological samples) of a fairly large scale on the Japanese
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Continuing literature survey on the health effects of
suspected endocrine disruptors and publishing the results
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