Press Release WHO/31
20 March 1998
WHO LEADS INTERNATIONAL HEALTH RISK ASSESSMENT
OF CHEMICALS WHICH DISRUPT HORMONAL ACTIVITIES
There is a rapidly growing body of scientific evidence indicating that a number of substances interfere with the normal functions of the body governed by the endocrine system and have, thus, the potential of causing adverse effects to health. One of the most impressive consequences of such hormonal interferences could be the decrease in sperm count and quality recently reported in a number of countries. Indications for an increase in the incidence of some hormonally sensitive carcinomas, including female breast cancers, as well as testicular and prostate cancers, could also be linked to the effects of these chemicals, called "Endocrine disruptors".
From now on, these chemicals will be under permanent scrutiny by a Steering Group of scientific experts, which met for the first time in Washington, DC, USA, on 16-18 March 1998, at the Pan American Health Organization, which is also the Regional Office of the World Health Organization (WHO) for the Americas. The meeting was jointly convened by the International Programme on Chemical Safety (IPCS) and the Organisation for Economic Co-operation and Development (OECD). The scientific experts who compose the Steering Group will provide guidance for and participate in the development of a global inventory of research on endocrine disrupting chemicals, as well as in the production of an international assessment of the "state of the science" on these substances under the auspices of the IPCS.
"The use of chemicals in practically every aspect of life has grown very rapidly over the last few decades", notes Dr Maged Younes, of the WHO Programme for the Promotion of Chemical Safety. "Out of over 11 million known chemicals, about 100 000 are being produced on an industrial scale and about 1000-2000 new chemical entities are being introduced each year. Human beings come into contact with many of the chemicals in commercial production, as well as thousands of substances of natural origin, which may be present as pollutants and contaminants in food, environmental media and commercial products."
Endocrine disruptors encompass a variety of chemicals, including natural and synthetic hormones, pesticides, monomers and additives used in the plastic industry, organometals, detergent components and breakdown products. They may interfere with hormones at various levels, including synthesis, storage, release and transport. Target organs potentially affected include male and female reproductive systems, the central nervous system, the thyroids and the immune system. There are also indications that exposure to endocrine disruptors could alter physical and mental development in children. According to specialists, hormonal disturbances may be expected to affect developing organisms more severely than adult organisms, and often such damage is permanent.
In assessing the risk to human health from exposure to endocrine disrupting chemicals, the same basic principles apply as in the case of any chemical. However, the endocrine system is complex by nature and multiple-organ interactions and effects are common. The establishment of a dose-response relationship, to determine what dose of a given substance is needed to compromise a functioning biological system, is a complicated task, because humans are often exposed to mixtures of chemicals. Even endogenous hormones, produced by the body, can interact with the endocrine system, making the situation all the more complex.
In spite of these difficulties, the concern expressed by international health authorities regarding the potential health effects of endocrine disruptors lead to the establishment of the Steering Group. A resolution on "persistent organic pollutants" was adopted in May 1997 by the World Health Assembly. It called upon the Director-General of WHO to "take the necessary steps to reinforce WHO leadership in undertaking risk assessment as a basis for tackling high-priority problems as they emerge, and in promoting and coordinating related research, for example, on potential endocrine-related health effects of exposure to chemicals and on the possible links with cancer and reproductive, neurological and immunological disorders".
The meeting in Washington is a first response to the international concern raised by endocrine disruptors. The International Programme on Chemical Safety, led by WHO, is collaborating with a number of national and regional agencies to establish and maintain an inventory of research activities on endocrine disruption. Work at the international level should help avoid duplication of efforts and coordinate research on this emerging phenomenon which poses a potential threat to public health all over the world.
For further information, journalists can contact Philippe Stroot, Media Relations, Health Communications and Public Relations, WHO, Geneva. Tel. 41 22) 791 2535 or Fax (41 22) 791 4858. E-mail:email@example.com
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