Exposure to BPA associated with reduced semen quality

October 28, 2010

Oakland, Calif.(October 28, 2010) -- Increasing urine BPA (Bisphenol-A) level was significantly associated with decreased sperm concentration, decreased total sperm count, decreased sperm vitality and decreased sperm motility, according to a Kaiser Permanente study appearing in the journal of Fertility and Sterility.

The five-year study recruited 514 workers in factories in China and compared workers who had high urine BPA levels with those with low urine BPA. Men with higher urine BPA levels had 2-4 times the risk of having poor semen quality, including low sperm concentration, low sperm vitality and motility.

This is the first human study to report an adverse association between BPA and semen quality. Previous animal studies found a detrimental association between BPA and male reproductive systems in mice and rats.

This study is the third in a series, published by Dr. Li and his colleagues, that examine the effect of BPA in humans. The first study, published in November 2009 in the Oxford Journals Human Reproduction, found that exposure to high levels of BPA in the workplace increases the risk of reduced sexual function in men. The second study, published in May 2010 in the Journal of Andrology, found that increasing BPA levels in urine are associated with worsening male sexual function.

Funded by the U.S. National Institute of Occupational Safety and Health, this new study adds to emerging human evidence questioning the safety of BPA, a chemical created in the production of polycarbonated plastics and epoxy resins found in baby bottles, plastic containers, the linings of cans used for food and beverages, and in dental sealants.

"Compared with men without detectable urine BPA, those with detectable urine BPA had more than three times the risk of lowered sperm concentration and lower sperm vitality, more than four times the risk of a lower sperm count, and more than twice the risk of lower sperm motility," said the study's lead author. De-Kun Li, MD, PhD, a reproductive and perinatal epidemiologist at Kaiser Permanente's Division of Research in Oakland, Calif. He added that urine BPA was not associated with semen volume or abnormal sperm morphology.

"Similar dose-response associations were observed among participants with only environmental BPA exposure at levels comparable to men in the general United States population," said Li.

Despite a markedly reduced sample size in this group of men exposed only to low environmental BPA sources, the inverse correlation between increased urine BPA level and decreased sperm concentration and total sperm count remain statistically significant, the researchers explained.

"The consistency of the findings between the current and the previous two studies, despite different exposure measurements (urine BPA levels vs. BPA exposure in the workplace) and end points (semen quality vs. sexual function), strengthens the validity of these findings," said Dr. Li. "The finding of the adverse BPA effect on semen quality illustrates two points: first, exposure to BPA now has been linked to changes in semen quality, an objective physiological measure. Second, this association shows BPA potential potency: it could lead to pathological changes of the male reproductive system in addition to the changes of sexual function."

The researchers explained that BPA is believed by some to be a highly suspect human endocrine disrupter, likely affecting both male and female reproductive systems. This new epidemiological study of BPA's effects on the male reproductive system provides evidence that has been lacking as the U.S. Food and Drug Administration and various other U.S. government panels have explored this controversial topic.

These findings, Dr. Li also points out, may portend adverse BPA effects beyond the male reproductive system. Semen quality and malesexual dysfunction could be more sensitive early indicators for adverse BPA effects than other disease endpoints that are more difficult to study, such as cancer or metabolic diseases.

For this study, workers in participating factories with and without BPA exposure in the workplace were identified and deemed eligible for the study. Among 888 eligible workers, 514 (58 percent) agreed to participate in the study. Of them, 218 participants provided both urine and semen specimens and were included in the final analyses. Through an in-person interview, participants provided information on demographic characteristics; potential risk factors that may influence semen quality including smoking, alcohol use, chronic diseases, history of sub-fertility, exposure to other chemicals and heavy metals; and recent exposure to heat sources such as a steam bath, as well as occupational history.
-end-
Other authors on this study include: J.R. Ferber, MPH, and L.J. Herrinton of the Kaiser Permanente Division of Research; Z. Zhou, PhD, MD, and Y. He, PhD, of the Department of Occupational Health and Toxicology, School of Public Health and WHO Collaborating Center for Occupational Health, Fudan University, Shanghai, China; M. Miao, PhD, J. Wang, PhD, E. Gao, MD, MPH, PhD, and W. Yuan of Shanghai Institute of Planned Parenthood Research and National Population and Family Planning Key Laboratory of Contraceptive Drugs and Devices.

About the Kaiser Permanente Division of Research (http://www.dor.kaiser.org/)

The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and the society at large. It seeks to understand the determinants of illness and well-being and to improve the quality and cost-effectiveness of health care. Currently, DOR's 400-plus staff is working on more than 250 epidemiological and health services research projects.

About Kaiser Permanente

Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America's leading health care providers and not-for-profit health plans. Founded in 1945, our mission is to provide high-quality, affordable health care services to improve the health of our members and the communities we serve. We currently serve 8.6 million members in nine states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: www.kp.org/newscenter.

http://www.kaiserpermanente.org

GolinHarris International

Related BPA Articles from Brightsurf:

Is exposure to BPA associated with long-term risk of death?
Whether exposure to bisphenol A (BPA), a chemical found in many consumer products, is associated with the long-term risk of death from cardiovascular disease, cancer or any cause among US adults was examined in this observational study.

Higher BPA levels linked to more asthma symptoms in children
Children in low-income neighborhoods in Baltimore tended to have more asthma symptoms when levels of the synthetic chemical BPA (Bisphenol A) in their urine were elevated, according to a study from researchers at the Johns Hopkins Bloomberg School of Public Health and School of Medicine.

Chemicals used to replace BPA may lead to increased blood pressure
Common bisphenol A (BPA) substitutes can affect the developing fetus and cause hypertension in later life, suggests a rodent study accepted for presentation at ENDO 2020, the Endocrine Society's annual meeting.

Think all BPA-free products are safe? Not so fast, scientists warn
Using 'BPA-free' plastic products could be as harmful to human health -- including a developing brain -- as those products that contain the controversial chemical, suggest scientists in a new study led by the University of Missouri and published in the Proceedings of the National Academy of Sciences.

BPA activates immune response in mice that passes down through generations
Some plastic food and beverage containers still contain bisphenol A (BPA), which can mimic the hormone estrogen.

BPA replacement hinders heart function, study reveals
BPA's counterpart replacement BPS can hinder heart function within minutes of a single exposure, according to a new University of Guelph study.

Study finds BPA levels in humans dramatically underestimated
Researchers have developed a more accurate method of measuring bispehnol A (BPA) levels in humans and found that exposure to the endocrine-disrupting chemical is far higher than previously assumed.

Bisphenol-a structural analogues may be less likely than BPA to disrupt heart rhythm
Some chemical alternatives to plastic bisphenol-a (BPA), which is still commonly used in medical settings such as operating rooms and intensive care units, may be less disruptive to heart electrical function than BPA, according to a pre-clinical study that explored how the structural analogues bisphenol-s (BPS) and bisphenol-f (BPF) interact with the chemical and electrical functions of heart cells.

BPA exposure during pregnancy can alter circadian rhythms
Exposure to the widely used chemical bisphenol A (BPA) during pregnancy, even at levels lower than the regulated 'safe' human exposure level, can lead to changes in circadian rhythms, according to a mice study to be presented Monday at ENDO 2019, the Endocrine Society's annual meeting in New Orleans, La.

Can prenatal exposures to BPA impact ovarian function?
While previous studies have shown the adverse health effects of prenatal exposure to the industrial chemical bisphenol A (BPA), there is little evidence surrounding effects specifically on ovarian function.

Read More: BPA News and BPA Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.