=======================Electronic Edition========================
RACHEL’S ENVIRONMENT & HEALTH WEEKLY #448
—June 29, 1995—
News and resources for environmental justice.
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ANOTHER STUDY SHOWS SPERM LOSS
Researchers in Belgium have reported a new study showing a
deterioration in sperm quality in young Belgian men since
1977. [1] The study provides new evidence supporting the
hypothesis that sperm quality has been deteriorating for 50 years
among men in industrialized countries. The Belgian study of 360
men (90% of them in the age group, 21 to 30) found a
statistically-significant reduction in sperm density (number of
sperm per milliliter of semen), as well as an increase in
misshapen sperm and in sperm with low motility (ability to swim
or move). (A milliliter is one thousandth of a liter, and a liter
is about a quart.)
The Belgian study compared men in 1977 to men in 1994 and
reported that, in 1977, 39.6% of sperm had a normal shape, but in
1994, the percentage of normal sperm had dropped to 27.8%. The
average number of sperm with strong motility dropped from 53.4%
in 1977 to 32.8% in 1994. Methods of analysis were unchanged
between 1977 and 1994, the researchers reported. The new study
was described at the 10th annual (1994) meeting of the European
Society of Human Reproduction and Embryology and has not been
fully published. [1] The new finding follows on a report earlier
this year in the NEW ENGLAND JOURNAL OF MEDICINE, that sperm from
men in Paris, France has deteriorated in quantity and quality
during the past 20 years. [2] The NEW ENGLAND JOURNAL OF
MEDICINE
report, itself, followed on an earlier study showing
deteriorating sperm during the last 20 years among men in
Scotland. [3] (See REHW #432.)
In what may be a related finding, researchers in Denmark in 1994
reported a much higher sperm count in organic farmers compared to
blue-collar workers (welders and printers). [4] Organic farmers
avoid the use of chemical fertilizers and pesticides and tend to
eat a diet high in chemical-free vegetables and dairy products.
The small group (30 men) had sperm densities more than twice as
high as blue-collar workers (363 million sperm per milliliter of
semen vs. 164 million per milliliter). The researchers reported
that this finding was “unexpected” and that they could provide no
plausible reason for the finding.
In the U.S., chemical-industry-sponsored researchers have begun
to attack the original study which suggested that sperm density
is dropping among men in industrialized countries. In 1992, a
historical analysis of 62 separate sperm-count studies, by
Elisabeth Carlsen, concluded that sperm count among men
throughout the industrialized world has declined by about 50%
during the past 50 years. [5] In 1994 this finding was challenged
by researchers who said that it might have been caused by
Carlsen’s erroneous choice of statistical methods, not by an
actual decline in sperm count. [6] Carlsen and her colleagues
defended their choice of statistical method (they had used a
simple linear model), saying their critics had simply
misunderstood what they had said and done. Now a new attack on
the Carlsen hypothesis has been published by researchers from Dow
Chemical and Shell Oil Company. [7] The Dow and Shell researchers
show that the use of more complex statistical models allow one to
conclude that sperm count has been INCREASING among men during
the past 20 years, not decreasing. The Dow and Shell researchers
do not comment on the most recent empirical studies, from France,
Scotland, and Belgium, showing decreases.
In related research, a scientist sponsored by the Chemical
Manufacturers Association (CMA) has attacked the whole idea that
estrogen-like industrial chemicals may be causing a host of
ailments in men and women, including breast cancer, endometrial
cancer, testicular cancer, birth defects of the penis,
undescended testicles, reduced sperm count and sterility. Danish
scientists had hypothesized that all these ailments may be
related to several dozen chemicals known to mimic the female sex
hormone, estrogen. [8] Now Professor Stephen Safe argues that
natural estrogen-mimicking chemicals in plants that we eat far
outweigh any effects we might experience from human-created
industrial chemicals. [9] “The suggestion that industrial
estrogenic chemicals contribute to an increased incidence of
breast cancer in women and male reproductive problems is not
plausible,” Professor Safe concludes.
To support his conclusion, Professor Safe had to ignore many
parts of the problem. [10] For example, as the British medical
journal, LANCET, notes, “Phyto-oestrogens from plants are
ingested daily but are readily metabolised and excreted.” The
LANCET’s point is that naturally-occurring estrogen-like
chemicals in plants enter the human body in our food, but they
are also broken down quickly, and leave the body. Industrial
chemicals may be stored in the body and mimic hormones for long
periods, years or decades, giving them long opportunities to
affect a person’s endocrine system, nervous system, and immune
system. Even very weakly estrogenic chemicals may be important
if they remain in the body for long periods.
Furthermore, Professor Safe doesn’t mention that the problem is
one of hormone balance and imbalance. All humans (males and
females) contain both androgens (male hormones) and estrogens
(female hormones); thus chemicals that mimic androgens or
estrogens, or chemicals that interfere with the body’s use of
androgens or estrogens, may disrupt the healthy balance of sex
hormones. Professor Safe concludes that a chemical can be
disregarded if it has no demonstrated estrogen-like activity.
For example, he dismisses p-p’-DDE (a breakdown byproduct of the
pesticide, DDT) as a cause of human problems because it does not
mimic estrogens. However, as we saw last week (REHW #447),
p,p’-DDT is now known to be a potent anti-androgen, and the class
of chemicals called anti-androgens may be responsible for many of
the effects attributed to estrogen-mimicking chemicals, including
cancer and reproductive disorders in both women and men. The
problem is far more complex than Professor Safe seems to think it
is.
Professor Safe examines four estrogen-mimicking pesticides to
which we are all exposed via our daily diet (DDT, dieldrin,
endosulfan, and p,p’-methoxychlor). He then generalizes about
the effects of these four pesticides, concluding that “dietary
exposure to xenoestrogens [non-natural estrogen-mimicking
chemicals] derived from industrial chemical residues in foods is
minimal compared to the daily intake of [estrogen-like chemicals]
from naturally-occurring [sources in our food].” [9] But four
pesticides do not represent all of the non-natural sources of
estrogen-like chemicals in our diet. On the contrary, the
industrial gender-bending chemicals in our diet remain largely
unidentified. Just this month, researchers reported that the
resin used to line 85% of the tin cans in the U.S. leaks
estrogen-like chemicals into the food inside the cans. [11]
Professor Safe’s conclusion, that industrial chemicals are
irrelevant to your hormones, is premature, to say the least.
The estrogen hypothesis –especially as it relates to breast
cancer –has been given increased credibility by recent analyses
in the PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES. [12] Even Dr. Bruce Ames –notorious for arguing that industrial chemicals
hardly ever hurt anyone (see RHWN #398)–now seems to agree that
sex hormones are related to as much as 30% of all cancer
cases. [13]
The endocrine system in humans and wildlife is as complicated as
the central nervous system. It controls reproduction, growth,
development, and behavior, particularly gender-related behavior.
It will be decades –or centuries –before it is understood.
Tinkering randomly with the hormones in such a system seems, on
the face of it, dangerous and unwise.
Meantime, while various scientists are making a good living
tinkering and arguing among themselves, 46,000 American women
will die of breast cancer this year and another 182,000 will
undergo surgery, radiation treatment or chemotherapy for the
disease. The 40-or-so chemicals that have already been
identified as hormone-mimickers are still being pumped and dumped
into the environment in billion-pound quantities each year. We
allow this to happen because we (as a society) assume chemicals
are innocent until proven guilty. Isn’t it time we turned that
assumption on its head, requiring corporate polluters to
demonstrate the absence of harm from their products before they
are released? Why do we tolerate this chemical trespass into our
most intimate property, our bodies? The present regulatory
system, which is GUARANTEED to cause great harm before we can
even begin to restrict the output of dangerous chemicals,
seems–to put it bluntly –so unworthy of a great nation, so
uncivilized.
                
                
                
                
    
–Peter Montague
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[1] K. Van Waeleghem and others, “Deterioration of sperm quality
in young Belgian men during recent decades,” HUMAN REPRODUCTION
Vol. 9, Supplement 4 (1994), pg. 73; this is an abstract, not a
full report.