Introduction to an Interim Reportfrom the Study Group on Health Effects of Endocrine
Disrupting Chemicals

Environmental Health Bureau, Ministry of Health and Welfare
Welfare,, Japan

1.

Background
The Study Group on Health Effects of Endocrine Disrupting Chemicals wasestablished in April 1998 under the Director General of the Environmental HealthBureau of the Ministry of Health and Welfare. The purpose of the Study Group is
to identify the issue of endocrine disrupting chemicals (hereinafter referred toendocrine disruptors) and to discuss approaches toward this issue.
The Study Group has held six sessions to date. During these sessions, theGroup reviewed effects on human health. Also, the Group invited experts fromforeign countries and international organizations such as WHO and OECD, andintroduced approaches of these organizations and foreign governments toward
these chemicals. The Study Group compiled and published an interim report in
the session held on November 9th, 1998 on the basis of findings and understanding
obtained through the previous sessions.

2.

Outline of the interim report
The report consists of four sections and an appendix. The four sections areindividually titled “Introduction,” “Examining Endocrine Disruptors,” “Strategyfor Resolving the Problems of Endocrine Disruptors,” and “Conclusion.”(1)

Introduction
This section describes the background of problems of endocrine disruptors

and what are points of these problems. The section also outlines thecircumstances under which the report was compiled.
The descriptions include:
zIndications that certain types of chemicals may have endocrine disrupting
actions at trace levels and may badly affect human health.

1zNeeds to take action, based on a tiered program, because many problems
remain to be resolved scientifically.

(2)

Examining Endocrine Disruptors
This section gives basic information required to understand human healtheffects of endocrine disruptors, such as hormonal actions in the human body andthe definition of endocrine disruptors by the International Programme on
Chemical Safety/the World Health Organization (IPCS/WHO). The section also
discusses expected action mechanisms of endocrine disruptors defined here andgives information on human health effects, based on domestic and international
documents and reports.
The IPCS defines an endocrine disruptor as “an exogenous substance or
mixture that alters function(s) of the endocrine system and causes adverse healtheffects in an intact organism, or its progeny, or (sub) populations.”
The information on human health effects given here includes effects on thefemale reproductive system and mammary glands such as uterine cancer,
endometriosis, and breast cancer; effects on the male reproductive system such as
decreased sperm counts, prostate cancer, testicular cancer, and hypospadias; andeffects on the thyroid system.
Based on currently available findings and documents, the followingevaluations are given:
1)

There have been no reports on definite causal relationships between
endocrine disruptors and health effects on humans, excluding instances
caused by diethylstilbestrol (DES) which was administered for possible
pharmacological actions on the endocrine system.

2)

It is possible to take temporary measures for exposure levels in everyday life,
if appropriate risk assessment and exposure evaluation are conducted.
However, in order to resolve endocrine disruptor problems, it is imperativethat the assumptions given below be established through assessments andevaluations.
① No hormonal control can be easily disrupted, although the fetal period isthough to be vulnerable.
② No unexpected synergistic effects are caused by multiple chemicals.
③ No unknown modes of activities exist at low dose levels.

2

(3)

Strategy for Resolving Problems of Endocrine Disruptors
This section shows approaches for endocrine disruptors which are being

conducted at home and abroad, and discusses basic policies to resolve problems
and research/studies to be performed to help secure human health.
The basic policies include concepts of chemical safety, the development of theinformation management/provision system, the promotion of international
cooperation, and the promotion of comprehensive research. Target problems

forresearch are divided into two groups: ①problems which require research toobtain needed data; ② problems which are expected to be resolved with thepromotion of state-of-the-art science.

(4)

Conclusion
As a conclusion of the report, this section indicates three matters we should

keep in mind, when placing in practice measures required to resolve endocrine
disruptor problems.
The matters are:1)

There are various questions to be deliberated in endocrine disruptor
problems.

2)

Endocrine disruptors are an issue to be handled globally.

3)

Endocrine disruptor problems may extend to multiple generations.

(5)

Appendix
This section reports the results of studies which were conducted on threechemicals used as ingredients of plastic containers for food use, and indicatesplans for future research/studies. Based on available study findings, the Study
Group has so far determined that it is not necessary to take immediate action
including “prohibition of use,” but that it is necessary to continuously conduct
more research/studies.
The three chemicals are:1)

Polycarbonate (bisphenole A)

2)

Polystyrene (styrene monomer, dimmer, and trimmer)

3)

Polyvinyl chloride (phthalates)3