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.

[2] 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.

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

[4] Annette Abell and others, "High sperm density among members of organic farmers' association," THE LANCET Vol. 343 (June 11, 1994), pg. 1498. Thanks to Marjorie Fisher for sending us a copy of this article.

[5] Elisabeth Carlsen and others, "Evidence for decreasing quality of semen during past 50 years," BRITISH MEDICAL JOURNAL Vol. 305 (1992), pgs. 609-613.

[6] Peter Bromwich and others, "Decline in sperm counts: an artefact of changed reference range of 'normal'?" BRITISH MEDICAL JOURNAL Vol. 309 (July 2, 1994), pgs. 19-22. Elisabeth Carlsen and some of her co-workers responded that Bromwich's analysis was "based on wrong assumptions" and "failed to give any empirical reference that might support [Bromwich's] assertion of differential selection." See Niels Keiding and others, "Importance of empirical evidence," BRITISH MEDICAL JOURNAL Vol. 309 (July 2, 1994), pg. 22.

[7] Geary W. Olsen and others, "Have sperm counts been reduced 50 percent in 50 years? A statistical model revisited," FERTILITY AND STERILITY Vol. 63, No. 4 (April, 1995), pgs. 887-893. Thanks to Jeff Pitt for sending us a copy of this article.

[8] Devra Lee Davis and others, "Medical Hypothesis: Xenoestrogens As Preventable Causes of Breast Cancer," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 101 (October 1993), pgs. 372-377. And: Richard M. Sharpe and Niels E. Skakkebaek, "Are oestrogens involved in falling sperm counts and disorders of the male reproductive tract?" THE LANCET Vol. 341 (May 29, 1993), pgs. 1392-1395.

[9] Stephen H. Safe, "Environmental and Dietary Estrogens and Human Health: Is There a Problem?" ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103, No. 4 (April, 1995), pgs. 346-351.

[10] Anonymous, "Male reproductive health and environmental oestrogens [editorial]," THE LANCET Vol. 345 No. 8955 (April 15, 1995), pgs. 933-935.

[11] Jose Antonio Brotons and others, "Xenoestrogens Released from Lacquer Coatings in Food Cans," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103, No. 6 (June 1995), pgs. 608-612.

[12] Satyabrata Nandi and others, "Hormones and mammary carcinogenesis in mice, rats, and humans: A unifying hypothesis," PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES USA Vol. 92, No. 9 (April 25, 1995), pgs. 3650-3657.

[13] Bruce N. Ames and others, "The causes and prevention of cancer," PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES USA Vol. 92, No. 12 (June 1995), pgs. 5258-5265.