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#750 - The Latest Hormone Science -- Part 1, 21-Aug-2002

Last week the NEW YORK TIMES took a slap at one of my favorite
organizations, the Science and Environmental Health Network or
SEHN (http://www.sehn.org). The TIMES accused SEHN of harboring
beliefs far outside the mainstream of science: "[SEHN] gives
much more weight than do most industry scientists and
government regulators to theories that chemicals in the
environment are disrupting the human endocrine system and
contributing to a wide range of ailments." (NY TIMES Aug. 19,
pg. C5.)

As president of the board of SEHN, I thought I should take this
accusation seriously. It is true that SEHN supports the view
that industrial chemicals in the environment can disrupt
hormones and by this means are probably contributing to a wide
range of human ailments. Is this view not generally held by the
mainstream scientific community?

SEHN's position has been stated best by science director, Ted
Schettler, a physician. Before he joined SEHN, Schettler, along
with several co-authors published GENERATIONS AT RISK:
230-page review of medical and scientific data showing that
some industrial chemicals in the environment (such as lead,
mercury, cadmium, arsenic, manganese, chlorinated solvents,
some pesticides, PCBs and dioxins) can and probably do
interfere with the hormone systems of humans (and non-human
animals), causing or exacerbating disease in some who are

In 2000, Schettler and SEHN board member David Wallinga (also a
physician) and other co-authors published a shorter book
book concluded that "Neurodevelopmental disabilities are
widespread, and chemical exposures are important and
preventable contributors to these conditions."[2, pg. 117; and
see RACHEL'S #712.] Is this conclusion warranted by the facts?
It certainly seems so. Scientific studies of a single toxic
element, lead, spanning the last 100 years provide ample
justification for such a statement. (Notably, the
hormone-disrupting characteristics of lead and about 75 other
environmental chemicals are described in three recent technical

Do "most industry scientists and government regulators"
disagree with Ted Schettler and SEHN? Neither we nor the NEW
YORK TIMES has any reliable information about what "most"
scientists and regulators think about hormone-disruptors. I
suspect the TIMES simply manufactured its conclusion out of
thin air. (Unfortunately, it wouldn't be the first time the
TIMES had done such a thing to belittle health dangers from
industrial chemicals. See, for example, RACHEL'S #346 and

Still, the accusation against SEHN warrants a fresh look. I
decided to investigate the current scientific status of the
idea that chemicals can interfere with hormones. To do so, I
chose one hefty scientific journal that often carries articles
about the effects of environmental chemicals on wildlife and
humans. Then I spent a grueling week reading every
chemicals-and-health study in the last 24 monthly issues. The
which is published by the federal government's National
Institute of Environmental Health Sciences, a division of the
National Institutes of Health. The editorial board of EHP is
composed mainly of academic scientists but it also includes
representatives from Dow Chemical Company, the Schering Plough
pharmaceutical company, and the Chemical Industry Institute of
Toxicology (CIIT). You can think of CIIT as the research arm of
the American chemical industry.

Of course I didn't start off completely ignorant. I had been
reporting on environmental hormone disruptors since 1991 (see
RACHEL'S #263). But I have to tell you, I wasn't prepared for
what I found. I'm going to summarize recent studies of
hormone-disrupters published in EHP, but first some background
on this problem:

In 1991, about two dozen scientists from half a dozen countries
published a consensus document that became known as The
Wingspread Statement. (See RACHEL'S #263.) It said in part,

"We are certain of the following:

"A large number of man-made chemicals that have been released
into the environment, as well as a few natural ones, have the
potential to disrupt the endocrine [hormone] system of animals,
including humans. Among these are the persistent,
bioaccumulative, organohalogen compounds that include some
pesticides (fungicides, herbicides, and insecticides) and
industrial chemicals, other synthetic products, and some

"Many wildlife populations are already affected by these
compounds. The impacts include thyroid dysfunction [impaired or
abnormal functioning] in birds and fish; decreased fertility in
birds, fish, shellfish, and mammals; decreased hatching success
in birds, fish and turtles; gross birth deformities in birds,
fish and turtles; metabolic abnormalities [impaired or abnormal
use of energy, manufacture of tissue, or handling of resulting
wastes] in birds, fish, and mammals; behavioral abnormalities
in birds; demasculinization and feminization in male fish,
birds, and mammals; defeminization and masculinization of
female fish and birds; and compromised [impaired] immune
systems in birds and mammals.

"The patterns of effects vary among species and among
compounds. Four general points can nonetheless be made: (1) the
chemicals of concern may have entirely different effects on the
embryo, fetus, or perinatal [meaning "near the time of birth,"
from the 28th week of pregnancy through the first week of life,
in humans] organism than on the adult; (2) the effects are most
often manifested in offspring, not in the exposed parent; (3)
the timing of exposure in the developing organism is crucial in
determining its character and future potential; and (4)
although critical exposure occurs during embryonic development
[from conception through the end of the second month of
pregnancy], obvious manifestations [effects] may not occur
until maturity.

"Laboratory studies corroborate the abnormal sexual development
observed in the field and provide biological mechanisms to
explain the observations in wildlife.

"Humans have been affected by compounds of this nature, too.
The effects of DES (diethylstilbesterol), a synthetic
therapeutic agent, like many of the compounds mentioned are
estrogenic [meaning they act like estrogen, female sex
hormone]. Daughters born to mothers who took DES now suffer
increased rates of clear cell adenocarcinoma [cancer], various
genital tract abnormalities, abnormal pregnancies, and some
changes in immune responses. Both sons and daughters exposed in
utero [while in the uterus] experience congenital anomalies of
their reproductive system and reduced fertility. The effects
seen in in utero DES-exposed humans parallel those found in
contaminated wildlife and laboratory animals, suggesting that
humans may be at risk to those same environmental hazards as
wildlife." The Wingspread Statement continued on, but those
were the key points.

The main message of the Wingspread Statement -- that industrial
chemicals can interfere with hormones and thus harm animals and
humans -- wasn't totally new in 1991. Researchers in 1950 had
demonstrated that the pesticide DDT could dramatically shrink
the testicles of roosters, obviously interfering with their
normal testosterone (male sex hormone).[4] In the early 1970s,
researchers discovered to their horror that "occupational
exposures to pesticides could diminish or destroy the fertility
of workers." [EHP Vol. 108, No. 9 (September, 2000), pgs.
803-813.] In 1980, the term "environmental estrogens" was
invented to describe industrial chemicals found in the
environment that behaved like the female sex hormone,

What the 1991 Wingspread Statement did was shine a spotlight on
an unrecognized world-wide pattern of harm from
endocrine-disrupting chemicals, mainly in wildlife, but also
plausibly in humans. The following year Theo Colborn, who had
convened the original Wingspread meeting, published a volume of
scientific evidence supporting the Wingspread conclusions.[6]
As time passed, these findings electrified the scientific
community, persuading thousands of researchers to look for
similar effects in wildlife, laboratory animals, and humans all
over the world.

In 1995 Theo Colborn, J.P Myers and Dianne Dumanoski published
OUR STOLEN FUTURE, a scientific treatise on hormones written
like a mystery story to reach a wide audience. OUR STOLEN
FUTURE awoke the environmental community and focused enormous
media attention on this emerging problem. The web site
http://www.ourstolenfuture.org is still the best single place
to learn about the latest hormone-disruptor studies. Because it
was scientifically solid yet easily readable by the general
public, OUR STOLEN FUTURE drove the chemical industry into a
frenzy of denial and retribution. They hired PR attack dogs
aiming to destroy the reputations of Colborn, Myers and
Dumanoski, and NY TIMES science writer Gina Kolata began
barking and snarling with the best of them (see RACHEL'S #486).

Now, 11 years after the Wingspread Statement, are these ideas
ridiculed, held in disrepute, or simply ignored by the
scientists who publish in EHP? Has the scientific community
moved beyond "endocrine disruptors" or is this problem still
being taken seriously? By way of answers to these questions,
here are a few general statements from EHP:

"Endocrine-disrupting chemicals are among the most complex
environmental health threats known today. By mimicking natural
hormones such as estrogen and testosterone, these chemicals can
interact with the body's endocrine system and exert toxic
effects that may lead to reproductive and developmental
abnormalities or cancer." [EHP Vol. 109, No. 9 (September
2001), pg. A420.]

"The developing organism is exquisitely sensitive to
alterations in hormone function. In the early embryonic state,
the gonads of human males and females are morphologically
[physically] identical. Sexual differentiation [turning a fetus
into a boy or a girl] begins under hormonal influence during
the fifth and sixth weeks of fetal development, and thus
alteration of hormone function during this highly sensitive
period can have profound, often debilitating, consequences. The
balance of estrogens and androgens [male hormones] is critical
for normal development, growth, and functioning of the
reproductive system. Although it is especially important during
development, this balance is important throughout life for
preservation of normal feminine or masculine traits.

"A number of environmental chemicals have actions that mimic or
alter the normal sex steroid hormones. The fetus is especially
vulnerable because this is the period of time when organs
develop. If the normal balance between estrogens and androgens
is disrupted, the result may be feminization of males,
masculinization of females, birth defects of the reproductive
organs, reduced fertility, and alteration of the expression of
normal feminine or masculine personality traits, probably
including sexual preference."[7]

To be continued.


[1] Ted Schettler, Gina Solomon, Maria Valenti, and Annette
ENVIRONMENT (Cambridge, Mass.: MIT Press, 1999). ISBN

[2] Ted Schettler, Jill Stein, Fay Reich, Maria Valenti, and
DEVELOPMENT (Cambridge, Mass.: Greater Boston Physicians for
Social Responsibility [GBPSR], May 2000). Available on the web
at http://www.igc.org/psr/ihwrept/ihwcomplete.pdf or as a paper
copy from GBPSR in Cambridge, Mass.; telephone 617-497-7440.

[3] See, for example, Lawrence H. Keith, editor, ENVIRONMENTAL
Wiley, 1997; ISBN 0471191264). See also M. Metzler, editor,
VOL. 3 (New York: Springer-Verlag, 2002; ISBN 3540422803); and
Louis Guillette, Jr. and D. Andrew Crain, ENVIROMENTAL
Taylor & Francis, 2000; ISBN 1560325712).

[4] H. Burlington and V.F. Lindeman, "Effect of DDT on testes
and secondary sex characteristics of white leghorn cockerels,"
MEDICINE Vol. 74 (1950), pgs. 48-51.

[5] Sheldon Krimsky, "An Epistemological Inquiry into the
Endocrine Disruptor Thesis," ANNALS OF THE NEW YORK ACADEMY OF
SCIENCES Vol. 948 (Dec., 2001), pgs. 130-142.

[6] Theo Colborn and Coralie Clement, editors,
Environmental Toxicology Vol. XXI] (Princeton, N.J.: Princeton
Scientific Publishing Co., 1992).

[7] EHP Vol. 110 Supplement 1 (February, 2002), pgs. 27

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