Endocrine Disrupters

A few weeks ago I received an anonymous communication in the mail that raised a real biological and medical concern, but presented a misleading interpretation. In case some of your readers received similar misleading information, I would like to clarify the situation.

The facts are beyond question and concern increasing evidence of estrogenic effects in humans and other species, as manifested particularly by falling sperm counts and decreasing sperm quality in otherwise healthy men over the past decades. In addition some fish species downstream from sewage works have exhibited feminization. These are considered to be hormonal in the broadest sense of the word.

What the source (a reprint from an unidentified publication) fails to explain is that many chemicals in widespread use throughout the world have "endocrine disrupter" activity, even though they may not be in themselves hormones. They act in a variety of ways: by mimicking the effects of estrogens or androgens (female and male hormones, respectively), by antagonizing the effects of normal hormones or changing their production, or by modifying the level of hormone receptors in the body so that normal hormone action may be increased or diminished.

These endocrine disrupters are to be found in an incredible variety of everyday products: household and industrial cleaners, pesticides and herbicides, solvents, dyes, paints, hairsprays to name a few. It is difficult to imagine how we can eliminate these exposures, but it is certainly important that industries limit the exposure of their employees, that environmental agencies such as the EPA act to reduce release of unwanted chemicals into the environment, and that individuals exercise caution in use of all such materials.

The above-mentioned article indicates that the urine from women taking estrogens (as contraception or post-menopausal replacement) is the main source of environmental estrogens. This might be true for fish immediately downstream of a drug manufacturer producing such compounds, but not for the general human population. Urban sewage probably contains hundreds of times more of the above mentioned endocrine disrupters than excreted estrogens.

Since the thrust of the article sent to me is that oral contraceptives are dangerous to the public health it is again totally misleading. The mechanism of action of oral contraceptives is to suppress the ovarian production of estrogens, so the net effect would be little or no increase in excreted estrogen. (It is also a fact that during pregnancy large amounts of estrogen and progesterone are manufactured and excreted, by humans as well as farm animals.) There are other means of controlling conception for both women and men, and undoubtedly there will be new developments in the future, which we can welcome, but not for fear of estrogens in the sewage. Meanwhile, I would reassure women and their partners that oral contraceptives are remarkably safe and effective for most couples.

Mary H. Frantz, M.D

February 23, 2002