NEW STUDY LINKS DDT TO BREAST CANCER
From: Hank Roth Kill
To: All Msg #9, 01-Sep-93 04:58am
Subject: DDE -1-
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/* Written 1993 by montague@world.std.com in igc:toxics.rachel */
/* ---------- "RACHEL: DDT & Breast Cancer" ---------- */
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--- April 22, 1993 ---
R A C H E L ' S H A Z A R D O U S W A S T E N E W S # 3 3 4
News and Resources for Environmental Justice
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: erf@igc.apc.org
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-1-
NEW STUDY LINKS DDT TO BREAST CANCER
Do trace residues of industrial chemicals harm humans?
A new study published yesterday in the JOURNAL OF THE NATIONAL
CANCER INSTITUTE reports that breast cancer in American women is
strongly associated with DDE (a form of DDT) in their blood.[1]
Breast cancer strikes 176,000 women in the U.S. each year, and
each year 46,000 die of it. DDE is a residue derived from the
well-known pesticide, DDT. DDT was banned in the U.S. in the
early 1970s but trace residues are still measurable nearly
everywhere in the environment. Furthermore, DDT is still heavily
used today in many locations outside the U.S.
The principal author of the new study, Dr. Mary Wolff at the Mt.
Sinai School of Medicine in New York, says, "[Our] findings
suggest that environmental chemical contamination with
organochlorine residues may be an important etiologic [causal]
factor in breast cancer. Given the world-wide dissemination of
organochlorine insecticides in the environment and the food
chain, the implications are far-reaching for public health
intervention worldwide."
The study shows that women with high levels of DDE in their blood
have a four-times-greater risk of breast cancer than women with
low levels of DDE in the blood. (In this case, "high" means 20
billionths of a gram of DDE in each milliliter of blood and "low"
means 2 billionths of a gram in each milliliter of blood. There
are 28.3 grams in an ounce, and 4.7 milliliters in a teaspoon.)
The study group was selected from 14,290 New York City women who
had attended a mammography (breast x-ray) clinic and had each
donated 30 milliliters of blood. Within the group of 14,290, 58
women who later developed breast cancer were selected for a case-
control study. The 58 "cases" were matched with 164 "controls,"
women from the large group who did not have breast cancer but who
were matched to the "case" women in several key respects (such as
age, menopausal status, and so forth). All their blood samples
were analyzed for DDE and PCBs. DDE is created when DDT is
metabolized (processed by a living organism that has eaten it).
PCBs are industrial chemicals originally used as insulators in
electrical equipment. PCBs were banned in the U.S. in 1976 but
are still measurable in all parts of the environment. (In the
study, PCBs were also associated with breast cancer but the
association was not statistically significant. There was one
chance in 6 that the association was due to random chance and
statistical significance was defined as one chance in 20, or
less.)
For fifty years, the incidence of breast cancer in American women
has risen at a steady 1 percent per year.[2] In 1940, an
American woman's lifetime risk of getting breast cancer was one
in 16. Today it is one in 8. (See Table 1, which shows the risk
of breast cancer in the U.S. today for women at various ages.)
However, death from breast cancer has remained steady throughout
the past 20 years because of life-saving, though brutal,
treatment methods (chemotherapy, radiation therapy, and surgery).
No one doubts that something in the environment is responsible
for the rising incidence of breast cancer in the U.S. Japanese
women have only one-fifth as much breast cancer as American
women; but when Japanese women move to the U.S., they are
stricken with breast cancer at U.S. rates.
Since the 1960s, medical specialists have been trying to track
down the causes of breast cancer. Throughout the 1980s, most
scientists believed that a high-fat diet caused breast cancer. A
study of diet and breast cancer in 120,000 women has now
discredited this theory and it has been abandoned.[2]
Researchers are now focused on the female hormones estrogen and
progesterone which, they suspect, may play a large role in breast
cancer.
It has been known since the early 1970s that breast cancer is
somehow related to estrogen. Beginning at menarche (the onset of
menstruation) and continuing until menopause, a women experiences
a sharply rising and falling exposure, first to estrogen and then
to progesterone, in a repeating 4-week ovulation cycle.
Late menarche and early menopause (both of which reduce a woman's
lifetime exposure to estrogen) are both associated with reduced
breast cancer risk. In addition, women who have their ovaries
removed early in life and are therefore exposed to much less
estrogen that other women, rarely have breast cancer.
Furthermore, women who have "estrogen replacement therapy" (i.e.,
take estrogen pills) have a 40 percent increased risk of breast
cancer, and women who use birth control pills have a 50 percent
increased risk of breast cancer. These clues all relate estrogen
to breast cancer.
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* Origin: The MotherLode BBS 788-5185 (1:363/168)
SEEN-BY: 13/13 133/2 151/100 143 1000 1003 363/3 32 34 81 118 157
SEEN-BY: 363/168 228 320 6969 365/47 369/35 374/1 12 14 17 46 98 147
SEEN-BY: 374/710 3607/1 3637/1 3641/1
From: Hank Roth Kill
To: All Msg #10, 01-Sep-93 04:59am
Subject: DDE -2-
*-*-* pnews conferences *-*-*
/* Written 1993 by montague@world.std.com in igc:toxics.rachel */
/* ---------- "RACHEL: DDT & Breast Cancer" ---------- */
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--- April 22, 1993 ---
R A C H E L ' S H A Z A R D O U S W A S T E N E W S # 3 3 4
News and Resources for Environmental Justice
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: erf@igc.apc.org
=======================================================================
-2-
But the EXACT relationship is not understood.
In recent years, menarche in American women has been occurring at
earlier and earlier ages. (Chinese women reach menarche at age
17; today U.S. women reach menarche at 12.8 years, on average,
but 200 years ago North American women reached menarche at age
17.) The declining age of menarche in U.S. women increases their
lifetime exposure to estrogen, which possibly increases their
risk of breast cancer.
What is causing the declining age of menarche? Some scientists
say simply, improved nutrition. Others say it may be caused by
industrial chemicals in our food that mimic hormones and
interfere with the internal mechanisms that regulate our bodies.
DDT, DDE, PCBs and dioxin are examples of chemicals now known to
mimic hormones and disrupt the endocrine system of fish, birds
and mammals, including humans.[3]
Dr. Patricia Whitten at Emory University in Atlanta, Ga., has
examined historical records extending back 200 years in several
countries. Dr. Whitten's concludes that improved nutrition
cannot account for all the changes in human reproduction that are
observable in the historical record. She believes that hormone-
mimicking industrial chemicals in the environment provide a more
satisfactory explanation.[4]
The debate over menarche has real consequences in the kinds of
research that scientists are doing. Scientists who believe
hormone-mimicking industrial chemicals may play an important role
are doing the kinds of studies reported today in the JOURNAL OF
THE NATIONAL CANCER INSTITUTE, examining hormone-mimicking
chemicals like DDT in relation to breast cancer.
On the other hand, those who believe improved nutrition provide
sufficient explanation for the change in menarche tend to ignore
external influences, such as environmental chemicals. Malcolm
Pike at University of Southern California (USC) School of
Medicine has emerged as a leader of this school of thought. Pike
argues as follows: nutrition is the cause of reduced age of
menarche; nutrition is unlikely to worsen, so we're stuck with
reduced age of menarche and therefore with increased exposure to
estrogen. Pike is experimenting with a technical fix, giving
women additional chemicals (pharmaceuticals) to block their
natural production of estrogen, then giving them controlled doses
of estrogen, to maintain their chemical balance artificially.
SCIENCE magazine reported January 29, 1993 that, "To the extent
it's possible to see a trend emerging in the 1990s, this anti-
estrogen strategy appears to be a leading contender." Dr. Walter
Willett at Harvard University's School of Public Health is in
Pike's camp. He says, "In the end, I think we're going to have
to go with a pharmacological fix." SCIENCE comments "There may
be some reluctance to support such experiments because people
feel they are 'unnatural.'" But, says Willett, "our whole
lifestyle is unnatural."
Dr. Wolff's new study does not definitively prove that chemical
residues cause breast cancer. The number of "cases" is small.
Additional research will be needed. Nevertheless, an editorial
in the JOURNAL OF THE NATIONAL CANCER INSTITUTE yesterday said,
"Because the findings of Wolff [and associates] may have
extraordinary global implications for the prevention of breast
cancer, their study should serve as a wake-up call for further
urgent research."[5]
--Peter Montague, Ph.D.
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[1] Mary S. Wolff and others, "Blood Levels of Organochlorine
Residues and Risk of Breast Cancer," JOURNAL OF THE NATIONAL
CANCER INSTITUTE Vol. 85 (April 21, 1993), pgs. 648-652.
[2] Eliot Marshall, "Search for a Killer: Focus Shifts From Fats
to Hormones," SCIENCE Vol. 259 (January 29, 1993), pgs. 618-621.
See also, Eliot Marshall, "The Politics of Breast Cancer,"
SCIENCE Vol. 259 (January 29, 1993), pgs. 616-617.
[3] Everyone interested in chemicals that mimic hormones must
read Theo Colborn and Coralie Clement, editors, CHEMICALLY-
INDUCED ALTERATIONS IN SEXUAL AND FUNCTIONAL DEVELOPMENT: THE
WILDLIFE/HUMAN CONNECTION [Advances in Modern Environmental
Toxicology Vol. XXI] (Princeton, N.J.: Princeton Scientific
Publishing Co., 1992).
[4] Patricia L. Whitten, "Chemical Revolution to Sexual
Revolution: Historical Changes in Human Reproductive
Development," in Theo Colborn and Coralie Clement, cited above,
pgs. 311-334.
[5] David J. Hunter and Karl T. Kelsey, "Pesticide Residues and
Breast Cancer: The Harvest of a Silent Spring?" JOURNAL OF THE
NATIONAL CANCER INSTITUTE Vol. 85 (April 21, 1993), pgs. 598-599.
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Table 1
Risk of Developing Breast Cancer Today in the U.S.
By age 25: one in 19,608
By age 30: one in 2525
By age 35: one in 622
By age 40: one in 217
By age 45: one in 93
By age 50: one in 50
By age 55: one in 33
By age 60: one in 24
By age 65: one in 17
By age 70: one in 14
By age 75: one in 11
By age 80: one in 10
By age 85: one in 9
Ever: one in 8
Source: See footnote 2.
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Descriptor terms: pesticides; ddt; dde pcbs; breast cancer;
morbidity; mortality; mary wolff; mt. sinai school of medicine;
new york; women; hormones; estrogen; endocrine disruptors;
menarche; menopause; estrogen replacement therapy; birth control
pill; the pill; patricia whitten;
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Hank Roth
