• 11 FEB 08
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    #858:Lowered sperm quality: Is it cellphones or chronic exposure to bisphenol A?

    This list was started to examine a range of health issues related to both electromagnetic radiation and chemical exposures and it is my belief that there is a huge overlap between the two. Consider the problem of declining sperm quality that has been reported from a number of researchers. Doing the rounds recently is the preliminary study from the prestigious Cleveland Clinic (below) and just reported in the Herald Sun in Australia on February 07, 2008.

    After spending a few weeks writing up a case study of the bisphenol-A controversy as part of a paper on chemical exposures in the workplace, I must take exception here and say that I think it is unlikely cell phones are a significant factor in this decline when you take into consideration what is now known about human exposure to bisphenol-A.

    Consider:

    Bisphenol-A (BPA) was recognised to be an endocrine disrupter and environmental estrogen in animals as far back as 1936 . In spite of that, BPA has long been a major product of the US chemical industry and is one of the highest volume chemicals produced worldwide with over 6.4 billion pounds being produced annually. It is used primarily in the manufacture of polycarbonate plastics and epoxy resins. This includes plastics used in food and drink packaging, such as baby bottles, and plastic resins used inside cans, bottle tops’ plastic containers used in the pharmaceutical industry, protective dental sealants and composite fillings and even plastic water supply pipes. We have been taking in BPA ever since that first sip at the baby bottle or dummy – far longer than our use of cell phones.

    The scientific literature relating to BPA toxicity were extensively discussed by five panels of experts prior to and during a meeting on 28-30 November 2006 in Chapel Hill, North Carolina. The meeting, titled: “Bisphenol A: An Examination of the relevance of Ecological, In vitro, and Laboratory Animal Studies for Assessing Risks to Human Health” was sponsored by NIEHS and the National Institute of Dental and Cranofacial Research (NIDCR) at the National Institutes of Health / Department of Health and Human Services (NIH/DHHS) and EPA. At the conclusion of the meeting an expert panel consensus statement, summarising the outcome from the meeting was agreed to and signed by 38 scientists from universities, research organizations and government agencies from the United States, Japan, the United Kingdom, Germany, Spain, and Italy.

    The Chapel Hill bisphenol A expert panel consensus statement
    The panel expressed concern that existing evidence clearly indicated that virtually everyone on the developed world has been exposed to chronic, low-level exposures to BPA, with more than 95% of people sampled having blood and urine levels exceeding the “low-dose” levels used in laboratory animals to elicit adverse health effects. In laboratory studies on animals exposed to BPA during their development and in adulthood the panel saw a wide range of adverse biological effects at exposure levels far below the U.S. EPA reference level of 50 ug/kg per day that was considered safe over a lifetime. This level was considered by the Panel as inappropriate for human exposure (long-term, low-level) as it was based on short-term, high-dose animal studies conducted in the 1980s. Since then there had been hundreds of laboratory studies published using low-dose levels which the Chapel Hill meeting wanted to integrate into the risk assessment of BPA. What these newer studies were suggestive of was a potential for similar adverse effects in humans at low-dose levels. The expert panel expressed concern that BPA exposure may be linked to recent increases in various human diseases such as prostate and breast cancer, abnormal penile/urethra development in male babies, early onset of puberty in girls, declines in semen quality in men, insulin resistant type 2 diabetes, obesity, attention deficit hyperactivity disorder (ADHD), autism and other neurobehavioral disorders.

    They also expressed concern that epidemiological studies to address the issue specifically for human exposure have largely not been done and listed a number of research avenues that should be explored to clarify the issues. This included studies on wildlife, both aquatic and terrestrial.

    As well as the overall Chapel Hill consensus statement a number of supportive review papers from the 5 Chapel Hill sub-panels were also published in Reproductive Toxicology. Some of the relevant findings from these papers are briefly summarised here:

    • Human exposure to bisphenol A: After reviewing the few epidemiological studies on human health and BPA exposure, studies on BPA emissions from consumer products and measured levels in the environment, as well as metabolic studies of animals the authors concluded that: “The reported levels of BPA in human fluids are higher than the BPA concentrations reported to stimulate molecular endpoints in vitro and appear to be within an order of magnitude of the levels needed to induce effects in animal models”.

    • In vitro molecular mechanisms of BPA action: According to the available evidence the authors were confident that multiple independent studies found that BPA can act as an estrogen with cell type specific effects; the developmental time of exposure and strength of dose were critical; depending upon a number of factors BPA can have a potency as high as the sex hormone estradiol ; and that BPA exhibits cell and tissue type specific effects with a dose response relationship “at the cellular and intracellular levels at low physiologically relevant concentrations”.

    • In vivo effects of BPA in laboratory rat studies: The authors reviewed the available literature on low-dose studies of rats exposed to levels below the 50 mg/(kg day) reference dose and concluded that: “We are confident that adult exposure to BPA affects the male reproductive tract, and that long lasting, organizational effects in response to developmental exposure to BPA occur in the brain, the male reproductive system, and metabolic processes. We consider it likely, but requiring further confirmation, that adult exposure to BPA affects the brain, the female reproductive system, and the immune system, and that development effects occur in the female reproductive system”.

    • Effects of environmental concentrations of BPA on wildlife: Extensive evidence from studies indicates that most of the reported effects on vertebrate wildlife species can be attributed to BPA binding to estrogen receptors on the cell surface. Effects on invertebrates are less certain at environmental levels but the overall evidence indicates that “no significant margin of safety exists for the protection of aquatic communities against the toxicity of BPA”.

    • Evaluating the carcinogenic activity of BPA: based on the available evidence the authors were confident that natural estradiol is a carcinogen as classified by the International Agency for Research on Cancer (IARC) and that “BPA acts as an endocrine disruptor with some estrogenic properties among other hormonal activities”. The authors saw as likely that BPA may be associated with increased cancers of the blood cell production system, and increases in tumours of the testes: BPA may alter the chromosome balance in some cells and tissues; early life exposure may predispose abnormal tissue (cancerous or benign) growth in the breast and prostate glands in adult life; and that prenatal exposures to environmental levels of BPA can alter “mammary gland development in mice, increasing endpoints that are considered markers of breast cancer risk in humans”.

    Now, for the Study (below) finding reduced sperm quality with increasing cell phone use the next step should be to test the subjects for BPA levels in their blood and urine. Would reduced sperm quality also be found to be related with increased BPA levels?

    Don

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    From the Cleveland Clinic, a major US hospital < http://www.clevelandclinic.org/>

    Do Cell Phones Affect Sperm Quality?

    http://cms.clevelandclinic.org/body.cfm?xyzpdqabc=0&id=227&action=detail&ref=500

    Oct. 23, 2006


    (WebMD) There just might be a connection between a suspected decline in male fertility and increased cell phone use, but experts say much more research is needed to confirm an association.In a study led by researchers from The Cleveland Clinic, men who used their cell phones the most had poorer sperm quality than those who used them the least.The lowest average sperm counts seemed to be in men who had the most cell phone use (more than four hours a day); those who didn’t use cell phones seemed to have the highest. Although the sperm count appears to go down with increasing cell phone use, the difference in numbers wasn’t significant.The findings do not prove a link between cell phone use and semen quality, researcher Ashok Agarwal, Ph.D., tells WebMD.
    Unanswered Questions
    Agarwal presented the study in a poster session at the 62nd annual meeting of the American Society for Reproductive Medicine in New Orleans.”This is still very preliminary and I would not want these findings misinterpreted as showing that cell phone use is a definite cause of decreased [male] fertility,” he says. “There are still many unanswered questions.”
    About a billion people worldwide now use cell phones, and some projections suggest that within the next five years that number could double.A link between cell phone use and reduced sperm counts has been suggested in several earlier studies, but none has been considered conclusive.Sperm Quality and Cell Phones

    The new study included 364 men being evaluated for infertility between September 2004 and October 2005.

    In addition to undergoing tests to determine sperm quantity and quality, the men answered questions about their cell phone habits.

    Most of the men had sperm counts that were well above the 20 million sperm per milliliter level that is considered the lower limit of normal. But the more the men in the study used their phones, the lower their sperm count tended to be.

    The average sperm count among men who said they did not use cell phones was 86 million per milliliter, compared with 76 million/mL for men who used cell phones less than two hours a day and 71 million/mL for men who used cell phones two to four hours a day.

    Men who reported using their cell phones more than four hours a day had the lowest average sperm counts — 66 million/mL.

    Significant downward trends were seen when other sperm-quality parameters were measured, such as percentages of sperm swimming well, alive sperm, and normal sperm shape.

    Laptops and Diapers

    Cell phones are not the only modern conveniences suspected of influencing sperm counts. At least one study has suggested that wearing disposable diapers as a baby can influence adult fertility, and another proposed a link between laptop use and sperm quality.

    [Don’s note: disposable diapers have an outer plastic lining containing bisphenol-A]
    But none of these suspected environmental influences has been proven to influence male fertility, says Rebecca Sokol, M.D., Ph.D., president of the Society for Male Reproduction and Urology.

    Her own research suggests a link between air pollution and declining sperm quality.

    Sokol calls the cell phone study “provocative” but far from conclusive.

    “This is an interesting observation that may lead to larger, more controlled studies to see if the observation holds up,” she tells WebMD.

    But she acknowledges that such studies may be difficult to do.

    An infertility specialist at the University of Southern California’s Keck School of Medicine, Sokol says there isn’t a lot she can tell patients when they ask about suspected environmental influences on male fertility.

    “I tell them what we know, which isn’t a lot,” she says. “We know that high (scrotal) temperature is bad for sperm, and we think that smoking, drinking, and marijuana use are probably bad. But we still have a lot to learn.”


    SOURCES: 62nd annual meeting of the American Society for Reproductive Medicine New Orleans, Oct. 21-25, 2006. Ashok Agarwal, Ph.D., director, Clinical Andrology Laboratory and Reproductive Tissue Bank; director of research, Reproductive Research Center, The Cleveland Clinic. Rebecca Sokol, M.D., Ph.D., president, Society for Male Reproduction and Urology; professor of medicine and obstetrics and gynecology, Keck School of Medicine, University of Southern California.
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