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#492 - What Causes Declining Sperm, 01-May-1996

NEW YORK TIMES writer Gina Kolata this week renewed her efforts to
discredit the theory and evidence that industrial chemicals interfere
with hormones, causing harm to wildlife and humans.[1]

A month ago, Ms. Kolata savagely attacked the new book, OUR STOLEN
FUTURE,[2] claiming that "careful studies" (none of which she cited)
had "refuted" the premise of the book. (See REHW #486.) OUR STOLEN
FUTURE reviewed hundreds of studies published in peer-reviewed
journals. The book offers substantial evidence that industrial
pollutants may be interfering with the hormones that regulate growth,
health and behavior in wildlife and humans, thus contributing to birth
defects, problems of sexual development, breast cancer, prostate
cancer, and even mental problems like attention deficit disorder,
diminished IQ, and violent behavior.

Among the evidence discussed in OUR STOLEN FUTURE was declining sperm
counts in men in industrialized countries, plus data and hypotheses
linking such a decline to hormone-disrupting chemicals. In 1992, a
report in the BRITISH MEDICAL JOURNAL[3] analyzed 61 previous sperm
studies conducted in 20 countries, concluding that average sperm counts
had declined from 113 million sperm per milliliter of semen to 66
million during the past 50 years, a 42% decline.

Ms. Kolata has made this her special cause, evidently determined to
convince TIMES readers that there's nothing to it. On the same day that
she maligned OUR STOLEN FUTURE (March 19th), Ms. Kolata published a
second article in the TIMES, about sperm counts.[4] It is clear from
Ms. Kolata's March 19th article that she requires little or no evidence
to be persuaded that sperm counts are not declining. Instead of
evidence, she offers two arguments:

(1) From 1960 to 1970 a million women were exposed to a synthetic sex
hormone called DES. Recently, a large study of male offspring of DES-
exposed mothers showed that these men are fertile, able to father
children.[5] Ms. Kolata apparently wants her readers to believe that
this means DES did not cause a decline in sperm counts among these men.

(2) Ms. Kolata offers her readers the opinion that infertility is not
increasing in the U.S.[6]

The important point is that these arguments are both straw men. Neither
argument reveals anything important about sperm counts. The original
analysis of 61 studies of sperm counts showed a decline from 113
million sperm per milliliter (ml) of semen in 1940 to an average of 66
million in 1990. Men are able to sire children with a sperm count as
low as 20 million sperm per ml, and they are not definitely sterile
until their sperm count drops to 5 million. No one has ever claimed
that average sperm counts world-wide have dropped this low. Ms. Kolata
has set up a straw man and triumphantly demolished it, but in the
process has misled her readers about the question of declining sperm
counts. (In fact a decline in sperm quality and quantity has been
reported among the sons of DES-exposed women, along with underdeveloped
and undescended testicles and stunted penises. These men were not
sterilized but the sperm of many of them was definitely diminished by
their mother's exposure to DES.)[7]

This week Ms. Kolata took up the sperm count cause again in the TIMES.
[1] On April 29, she reviewed three recent studies of sperm, omitting
mention of other recent studies that don't support her bias. She
highlighted two new studies that indicate sperm counts have slightly
INCREASED over the past 25 years among students in Seattle,[8] and
among men preparing to have vasectomies in Los Angeles, New York, and
Roseville, Minnesota.[9] Ms. Kolata describes a third study, by Harry
Fisch, which re-analyzes the 61 previous studies.[10]

Ms. Kolata gives great weight to Dr. Fisch's re-analysis of the 61
studies, which concludes that sperm counts may not be declining
worldwide. Dr. Fisch argues that the "decline" in sperm counts is
really just previously-unnoticed "geographic variation" in sperm
counts. In other words, Dr. Fisch argues that sperm counts may not
actually be declining; instead, they may be holding steady, but they
may APPEAR to be declining because there is so much variation between
sperm counts in different locations.

Ms. Kolata failed to mention it, but to reach his new conclusions about
worldwide sperm counts, Dr. Fisch threw out 41 of the 61 original
studies, re-analyzing only 20 of the original 61. He says he did this
because the study populations in those 41 studies were small, involving
all together only 9% of the original total study population. However,
in so doing, Dr. Fisch reduced the number of countries involved from 20
to only 12. On the basis of the much smaller number of studies, from
the much smaller number of countries, he concluded that sperm counts
have not declined. Exclusion of so many relevant studies seems dubious
at best.

Ms. Kolata explains Dr. Fisch's findings this way: "Dr. Fisch argues
that the decline reported was probably a result of previously
unappreciated regional variations in sperm counts. Most of the early
studies, with the high sperm counts, involved New York men, whose sperm
counts have remained among the highest in the world. Most of the more
recent studies involved men from developing countries and their sperm
counts, for unknown reasons, tend to be lower." But is this true? Is
Paris in a developing country?[11] Is London?[12] Is Brussels?[13] Is
Scotland a developing country?[14] These are all places where good
recent studies have reported declining sperm counts.

Ms. Kolata chose not to tell her TIMES readers about these important
recent studies.

One new study reveals that sperm quantity has not changed for 20 years
in rural Toulouse, France.[15] The authors of the Toulouse study
suggest that environmental factors might distinguish Toulouse from
Paris, where sperm counts seem to be declining. Combined with the two
new U.S. studies, does the Toulouse study mean that all the other
recent studies showing declines are wrong?

The U.S. studies do not seem particularly persuasive. Students in
Seattle are unlikely to be representative of the general populace.
Neither, necessarily, are a self-selected population of men preparing
to have vasectomies. A general decline in sperm counts could be
occurring, yet might not be revealed by studies of these particular
populations.

Based on the Toulouse study, we can say that it is good news that some
populations can be found who may not be experiencing declines in sperm.
But it is not news that some populations have high sperm counts and
others have low. The original analysis of 61 studies in 1992 made this
very clear. No matter what is happening to the worldwide average, the
question therefore remains: why is sperm count in some large
populations low and/or declining? Gina Kolata seems to want her readers
to believe that declines are not occurring and that low counts occur
only in developing countries. But in his analysis Harry Fisch
acknowledges the problem, and answers it this way: the "geographic
variations" in sperm might be caused by environmental factors,
nutrition, socioeconomic differences, or some other "unknown causes,"
he says.[10]

In other words, it is entirely possible that "environmental factors,"
such as hormone-disrupting chemicals, are affecting some large
populations, causing a decline in sperm. Back in 1983, U.S. EPA
[Environmental Protection Agency] identified 52 chemicals or groups of
chemicals that adversely affected sperm (as well as 11 that enhanced
sperm).[16] We have already seen that DES had adverse effects on the
sperm of sons of DES-treated women. Is there laboratory data supporting
such an idea?

Elaborate new studies of mice, reported in ENVIRONMENTAL HEALTH
PERSPECTIVES (a U.S. government publication) in December, reveal that
exposing pregnant mice to low levels of an estrogenic chemical causes
their male offspring to develop smaller-than-normal testicles, and to
produce less sperm than untreated mice.[17] Three separate industrial
chemicals (with estrogenic properties) were tested and they all caused
small testicles and diminished sperm counts. (DES was also tested, as a
"positive control," and --no surprise --it had the same effect.) The
estrogenic chemicals used in these experiments are industrial
pollutants commonly found in our food and water.

Gina Kolata chose not to tell her TIMES readers about these important
new animal studies.

--Peter Montague

=====

[1] Gina Kolata, "Are U.S. Men Less Fertile? Latest Research Says No,"
NEW YORK TIMES April 29, 1996, pg. A14

[2] Theo Colborn, Dianne Dumanoski, and John Peterson Myers, OUR STOLEN
FUTURE (N.Y.: Dutton, 1996).

[3] Elisabeth Carlsen and others, "Evidence for decreasing quality of
semen during past 50 years," BRITISH MEDICAL JOURNAL Vol. 305 (1992),
pgs. 609-613. We have previously reported on this study, and subsequent
studies. See REHW #290, #343, #369, #390, #436, #438, #446, #447, #448,
#457.

[4] Gina Kolata, "Sperm Counts: Some Experts See a Fall, Others Poor
Data," NEW YORK TIMES March 19, 1996, pg. C10.

[5] Allen J. Wilcox and others, "Fertility in Men Exposed Prenatally to
Diethylstilbestrol," NEW ENGLAND JOURNAL OF MEDICINE Vol. 332, No. 21
(May 25, 1995), pgs. 1411-1416.

[6] There is some evidence that this is untrue. Congress's Office of
Technology Assessment (OTA) reported several years ago that Americans
in their prime reproductive years (ages 20 to 24) have experienced an
increase in infertility in recent years. See "Reproductive Dysfunction
in the Population," in U.S. Congress, Office of Technology Assessment,
REPRODUCTIVE HEALTH HAZARDS IN THE WORKPLACE [OTA-BA-266] (Washington,
DC: U.S. Government Printing Office, 1985), pgs. 341-364.

[7] The evidence is reviewed in Leon Earl Gray, Jr., "Chemical-Induced
Alterations of Sexual Differentiation: A Review of Effects in Humans
and Rodents," in Theo Colborn and Coralie Clement, editors, CHEMICALLY-
INDUCED ALTERATIONS IN SEXUAL AND FUNCTIONAL DEVELOPMENT: THE
WILDLIFE/HUMAN CONNECTION (Princeton, N.J.: Princeton Scientific
Publishing Co., 1992), pgs. 203-230. And see J.A. McLachlan, "Rodent
Models for Perinatal Exposure to Diethylstilbestrol and Their Relation
to Human Disease in the Male," in A.L. Herbst and H.A. Bern, editors,
DEVELOPMENTAL EFFECTS OF DIETHYLSTILBESTROL IN PREGNANCY (New York:
Thieme-Stratton, Inc., 1981), pgs. 48-157. And see: W. Gill, "Effects
on Human Males of IN-UTERO Exposure to Exogenous Sex Hormones," in T.
Mori and H. Nagasawa, editors, TOXICITY OF HORMONES IN PERINATAL LIFE
(Boca Raton, Florida: CRC Press, 1988), pgs. 162-174.

[8] C. Alvin Paulsen and others, "Data from men in Greater Seattle area
reveals no downward trend in semen quality: further evidence that
deterioration of semen quality is not geographically uniform,"
FERTILITY AND STERILITY Vol. 65, No. 5 (May, 1966), pgs. 1015-1020.

[9] Harry Fisch and others, "Semen Analyses in 1,283 men from the
United States over a 25-year period: no decline in quality," FERTILITY
AND STERILITY Vol. 65, No. 5 (May, 1996), pgs. 1009-1014.

[10] Harry Fisch and Erik T. Goluboff, "Geographic variations in sperm
counts: a potential cause of bias in studies of semen quality,"
FERTILITY AND STERILITY Vol. 65, No. 5 (May, 1996), pgs. 1044-1046.

[11] Jacques Auger and others, "Decline in Semen Quality Among Fertile
Men in Paris During the Past 20 years," NEW ENGLAND JOURNAL OF MEDICINE
Vol. 332, No. 5 (February 2, 1995), pgs. 281-285.

[12] D. Stewart Irvine, "Falling sperm quality," BRITISH MEDICAL
JOURNAL Vol. 309 (August 13, 1994), pg. 476.

[13] 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.

[14] Stewart Irvine and others, "Evidence of deteriorating semen
quality in the United Kingdom: birth cohort study in 577 men in
Scotland over 11 years," BRITISH MEDICAL JOURNAL Vol. 312 (February 24,
1996), pgs. 467-471.

[15] L. Bujan and others, "Time series analysis of sperm concentration
in fertile men in Toulouse, France between 1977 and 1992," BRITISH
MEDICAL JOURNAL Vol. 312 (February 24, 1996), pgs. 471-472.

[16] Andrew J. Wyrobek and others, "An evaluation of human sperm as
indicators of chemically induced alterations of spermatogenic
function," MUTATION RESEARCH Vol. 115 (1983), pgs. 73-148.

[17] Richard M. Sharpe and others, "Gestational and Lactational
Exposure of Rats to Xenoestrogens Results in Reduced Testicular Size
and Sperm Production," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103, No.
12 (December, 1995), pgs. 1136-1143. The chemicals tested were 4-
octylphenol (OP), butyl benzyl phthalate (BBP), and octylphenol
polyethoxylate (OPP). BPP is a phthalate, many of which are common in
the environment and in our food because they are widely used as
plasticizers.

Descriptor terms: sperm count; hormones; hormone disrupters; new york
times; gina kolata; our stolen future; des; infertility; 4-octylphenol;
butyl benzyl phthalate; octylphenol polyethoxylate; los angeles; new
york; seattle; studies;