Warning on breadth of hormone chemical effects

Potential sex-related changes may be least significant effect of exposure, say Swedish researchers

Swedish scientists have warned that public debate on hormone-disrupting chemicals has been too focused on potential effects on sexual hormone systems. Changes to other systems could be more important, the scientists conclude from an assessment of international research literature, including possible effects on behaviour, intelligence and cancer formation.

Published today by the Swedish Environmental Protection Agency (EPA), the report ranks neuro-behavioural changes in humans as the most "probable" effects of exposure to hormone-disrupting chemicals. The next most likely is thought to be cancer formation, including cancers of the breast, endometrium, prostate and testes.

Lowest in the ranking of possible effects, based on evidence from research carried out so far, is falling sperm counts. This is despite the fact that the hormone disrupters are commonly referred to in public debate as "sex change chemicals" or, more colloquially, as "gender benders".

According to the principal author of the report, Per-Erik Olsson of Umeå University, several studies have found potential effects on thyroid hormones, which regulate brain development among other things, and retinoids, which regulate growth and metabolism. But public debate had been fixated on chemicals affecting sexual hormones, and in particular oestrogen, he said. "We should have a more balanced debate," Professor Olsson told ENDS Daily.

The report investigates the relationship between the chemical structures of suspected hormone-disrupting chemicals and the workings of hormonal systems in animals and humans. For example, Professor Olsson says, the chemical structure of thyroid hormones suggests great potential for interaction with similarly structured halogenated organic compounds. He adds that looking at other hormonal systems could provide the key to explaining effects on human reproduction, as there could be subtle interactions between the systems.

Commissioned by the Swedish government to advise on research priorities relating to hormone disrupters, the report is also timely in terms of international policy-making. This autumn, both the European Commission and the European Parliament are due to produce reports recommending further research and other action on hormone-disrupting chemicals. The US Environmental Protection Agency, meanwhile, is reported to be due shortly to launch a major programme to screen more than 15,000 chemicals for their potential to interfere with hormonal systems.

Follow Up:
Swedish EPA, tel: +46 8 698 1000. References: "Report 4859: Endocrine Disrupting Substances."

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