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.
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.
Danielle Cass | EurekAlert!
Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View
22.06.2018 | University of Sussex
New cellular pathway helps explain how inflammation leads to artery disease
22.06.2018 | Cedars-Sinai Medical Center
Russian researchers together with their French colleagues discovered that a genuine feature of superconductors -- quantum Abrikosov vortices of supercurrent -- can also exist in an ordinary nonsuperconducting metal put into contact with a superconductor. The observation of these vortices provides direct evidence of induced quantum coherence. The pioneering experimental observation was supported by a first-ever numerical model that describes the induced vortices in finer detail.
These fundamental results, published in the journal Nature Communications, enable a better understanding and description of the processes occurring at the...
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
25.06.2018 | Physics and Astronomy
25.06.2018 | Earth Sciences
25.06.2018 | Power and Electrical Engineering