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Studies Continue to Raise Serious Health Concerns over BPAMay 1, 2010
Studies Continue to Raise Serious Health Concerns over BPA
BPA (bisphenol-A), an estrogen-like chemical compound, is one of the world’s most abundantly produced chemicals (3 million tons annually) that is used in the production of PVC pipes, epoxy resins that line food cans, food packaging, and drink containers. BPA is also used in dental sealants, baby bottles, and toys. BPA is a component of polycarbonate plastics contained in many consumer products. It is also present in drinking water and in household air, in the form of dust.
While the highest levels of the chemical were found in cans of green beans, it has also been found in the liquid contained in cans of peas, beans, artichokes, mixed vegetables, corn, and mushrooms. The most recent study released by the National Workgroup for Safe Markets, a coalition of more than 17 public and environmental health groups, analyzed 50 cans of food from 19 U.S. states and Ontario, Canada. BPA was found in an 92% of the samples, with the top level being the highest yet reported in the U.S. (1,140 parts per billion contained in a can of Del Monte French Style Green Beans from Wisconsin).
Research has repeatedly shown that BPA leaches out of products and may be absorbed into the body at low concentrations. Those low doses, however, appear to be sufficient to pose numerous (quite serious) health risks as a result of multiple animal studies as well as those which analyzed available human data.
Based on its widespread use in all of the above products, experts were not surprised to learn that, based on urine samples, BPA was probably present in the bodies of more than 90% of American adults.
Some have argued that, while BPA is certainly present in a variety of plastics, the amount that actually makes its way into our foods is insignificant. Mike Schade, co-author of the study, said, however, that “real-life meals involving one or more cans of food can cause an individual to ingest levels of BPA that have been shown to cause health effects in laboratory animal studies.” The report further warns that the BPA was found across the board, regardless of brand, nutritional quality, or the price of the foods.
Sen. Dianne Feinstein (Dem. Ca.) has already called for a ban on BPA in food and beverage containers stating in an article in the Huffington Post: “Nearly 200 scientific studies show that exposures to low doses of BPA, particularly during pregnancy and early infancy, are associated with a wide range of adverse health effects later in life.”
BPA has already been linked to coronary disease. In 2003-2004, the CDC began testing a representative sample of Americans for BPA as part of the National Health and Nutrition Examination Survey (NHANES) data-collection study.
David Melzer, PhD, of Peninsula Medical School in Exeter, England, led a research team which analyzed the data and found that high levels of BPA were linked to a high risk of heart disease. Their study results were published in the September 17, 2008 issue of the Journal of the American Medical Association (JAMA).
Although some critics of the NHANES study claimed that because it examined so many variables, one would be bound to appear risky, just by chance. Dr. Melzer, however, denies that the previous finding with respect to BPA was a statistical blip since he and his team have recently analyzed a new set of CDC (Centers for Disease Control) data collected from 2005-2006, and this study revealed that even though BPA levels were 30% lower, people with the highest BPA levels still had a significantly greater risk of heart disease; a 33% greater risk, to be exact.
"It is very clear that the connection is still there," Melzer said. "It underlines the question mark we found between BPA and human health." Contrary to the first study, however, the second one showed no considerable association between BPA and diabetes or liver enzymes. Although, when data from both years was pooled, these links were highly apparent. Urinary levels of BPA were significantly higher in people with diagnoses of angina, coronary heart disease, and diabetes, those who had suffered heart attacks, and those with elevated liver enzymes.
The study used data from 1,455 participants in the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2004 in whom urine levels of BPA and creatinine were measured. The researchers then correlated BPA levels with the presence of several common disorders.
After appropriate adjustments for age, sex, urinary creatinine, race and ethnicity, education, income, smoking status, body mass index, and waist circumference, the researchers found the “odds ratios” for each standard deviation of urinary BPA above the mean for the following diseases: angina, coronary heart disease; heart attack, all cardiovascular disease; and diabetes.
The researchers, who did not recommend restricting BPA use on the basis of their findings, also looked for, but did not find, possible links to cancer, arthritis, overt liver disease, chronic respiratory diseases, stroke, and thyroid disease.
Non-Hispanic blacks had significantly higher mean levels of the compound than non-Hispanic whites. Participants ages 18 to 29 had higher mean levels than those 60 to 74. Although mean BPA levels tended to be higher in those with body mass index of 35 or greater than those with BMI below 25, the difference was not of statistical significance.
Gina Solomon, MD, senior scientist at the environmental group National Resources Defense Council, says the study is instrumental in helping to solve the BPA puzzle. "Already we know that BPA is associated with diabetes and metabolic disturbances, so it is not surprising this carries out to heart disease," Solomon said. "These results make sense and really increase our level of concern that BPA is a public health threat."
This study came on the heels of a 2008 controversy in which the FDA evaluated BPA studies and deemed the substance to be acceptably safe. The FDA assessment drew serious criticism from Congress as well as the Agency’s own science advisory board.
The National Toxicology Program wrote a report based on the same studies and contradicted the FDA’s evaluation that BPA was not dangerous to humans. FDA Commissioner, Margaret Hamburg, said that the National Toxicology Program analysis used different methods and outcomes than the FDA's initial review, and the agency now shares the National Toxicology Program's conclusions. She continued by saying that the FDA now acknowledges BPA is of “some concern” and the agency is conducting its own studies on the chemical, cooperating with the National Institutes of Health, which are expected to be completed soon.
The National Institute of Environmental Health Sciences (NIEHS) says there is some concern about BPA safety for fetuses, infants, and children, but minor concern over the chemical's reproductive toxicity for adults.
There is no way to avoid BPA entirely, but the NIEHS offers this advice for people who want to reduce their exposure to BPA: (1) Do not microwave polycarbonate plastic food containers. Polycarbonate is strong and durable, but over time it may break down from overuse at high temperatures; (2) Polycarbonate containers that contain BPA usually have a No. 7 on the bottom, although not all containers with a No. 7 contain BPA; (3) Reduce your use of canned foods; (3) When possible, opt for glass, porcelain, or stainless steel containers, particularly for hot food or liquids; and (4) Use baby bottles that are BPA-free.
No final conclusions have been reached concerning the specifics of how BPA affects the heart. While Dr. Melzer’s studies show a link between BPA and heart disease, this does not prove BPA actually cause heart disease.
A number of scientists maintain that it is necessary to learn more about what causes the health risks identified in the BPA studies, especially whether they are caused by BPA itself or by something else linked to BPA exposure. While Melzer’s researchers theorize that the metabolization of BPA may induce oxidative stress and endothelial cell damage. However, there is no significant evidence to support this and the researchers said further studies evaluating the association and its mechanisms are needed.
The researchers stressed that independent duplication of the findings is now needed to confirm the associations and to provide evidence as to whether the associations are causal. They also noted that the urinary concentrations on which they based their analysis only reflected recent exposure. Thus, "Repeat measurements over weeks, months, or even years would improve the assessment of longer-term exposure."
In the accompanying editorial by Frederick vom Saal, Ph.D., of the University of Missouri, and John Peterson Myers, Ph.D., of Environmental Health Sciences in Charlottesville, Va., the writers concluded that it was not too soon for federal regulators to act on this new data.
The editorial stated: "The study...while preliminary with regard to these diseases in humans, should spur U.S. regulatory agencies to follow the recent action taken by Canadian regulatory agencies, which have declared BPA a 'toxic chemical' requiring aggressive action to limit human and environmental exposures."
Drs. vom Saal and Meyers also claimed that "an aggressive disinformation campaign," was designed to undermine the reliability of independent scientific findings on the compound's dangers. This, they argue has discouraged the FDA and European regulators from restricting BPA use.
As previously reported, more than 100 studies published in peer-reviewed journals have shown the detrimental effects of BPA.
The researchers in the Melzer study also cited previous animal studies on BPA as "overwhelming evidence of harm." (see below). They also expressed concern that banning the chemical may not stop its continued contributions to disease since: "Eliminating direct exposures from its use in food and beverage containers will prove far easier than finding solutions for the massive worldwide contamination by this chemical due its disposal in landfills and the dumping into aquatic ecosystems of myriad other products containing bisphenol A, which Canada has already declared to be a major environmental contaminant."
In December 2005, a study found that BPA disrupts brain development. A University of Cincinnati (UC) research team later reported in two articles in the journal Endocrinology that BPA shows negative effects in brain tissue "at surprisingly low doses."
Although best known for its function as a female sex hormone, estrogen also has very important roles in the developing brain of both males and females. According to team leader, Dr. Scott Belcher: "These new studies are also the first to show that estrogen's rapid signaling mechanisms are active in the developing and maturing brain in regions not thought to be involved with sexual differences or reproductive functions."
Dr. Belcher is an associate professor in the pharmacology and cell biophysics department at UC College of Medicine. He stated that: "BPA molecules are linked into polymers used to create polycarbonate plastics and epoxy resins that are widely used in many products. While plastics are typically thought of as being stable, scientists have known for many years that the chemical linkage between BPA molecules was unstable, and that BPA leaches into food or beverages in contact with the plastics."
This particular study utilized rats at a period in their development equivalent to the third trimester of human fetal development through to the first few years of childhood. In the absence of estrogen, BPA alone was found to mimic the actions of estrogen in developing neurons. Very low doses of BPA completely inhibited the activity of estrogen. Since estrogen normally increases the growth of neurons and regulates their viability during development, these results support the theory that BPA may harm developing brain cells.
The most startling and disturbing finding, however, was that near-maximal effects of BPA on rat brain neurons occurred "at surprisingly low" doses of only 0.23 parts per trillion and happened in a matter of minutes.”
These low-dose results indicate that BPA may be inflicting maximal damage at levels found in developing fetuses and typical human exposure thereby raising the possibility that detection is being missed by standard approaches used in measuring chemical exposure.
According to Dr. Belcher: "Estrogen's actions on these neurons appear to be a double-edged sword. During certain periods of development estrogen can kill specific subsets of neurons, but at a later developmental stage it actually appears to increase their viability."
Any disruption of either of these actions of estrogen could be considered potentially harmful, Dr. Belcher added. "We have now shown that environmental estrogens like BPA appear to alter, in a very complicated fashion, the normal way estrogen communicates with immature nerve cells. The developmental effects that we studied are known to be important for brain development and also for normal function of the adult brain."
Despite the fact that plastics free of BPA and other toxic chemicals are already available, the chemical industry and every federal agency charged with regulating such compounds have resisted all efforts to have BPA banned.
In June 2005, a Japanese Study linked BPA to recurrent miscarriages. BPA (already implicated as a possible cause of breast cancer in a May 2005 study, below) was linked to recurrent miscarriages in a study at Nagoya City University Medical School published in Human Reproduction Magazine. The researchers, led by Dr. Mayumi Sugiura-Ogasawara of the OBGYN department, examined 77 women. Of that group, 45 had suffered three or more consecutive miscarriages and 32 had a history of successful pregnancies.
The women in the miscarriage group were found to have average BPA levels approximately three times higher than those who had not miscarried. Because of the small size of the study, further research is needed into the precise nature of the effect BPA has on human reproduction.
A May 2005 study found a link between BPA and Breast Cancer. This animal study suggests that even at extremely low concentrations, BPA exposure in the womb may be harmful. Moreover, the study uncovered evidence that BPA may be a breast cancer risk factor because of its potential effect on the development of vulnerable and sensitive breast tissue.
In January 2005, BPA was shown to Increase the growth of prostate cancer cells. A study conducted by a research team at University of Cincinnati and published in the January 2005 issue of the journal Cancer Research reported that BPA increased the growth of some prostate cancer cells.
All of these studies as well as many others offer considerable proof that the experts and political leaders, who are seeking to ban BPA, or at least a significant restriction on its use, are not simply “crying wolf.”
The evidence is clearly more than conjecture or speculation, and it raises the question of why the FDA is moving so slowly on this issue while a potential time bomb is ticking away in every household, school, and supermarket in the country.
Parker Waichman LLP has been in the forefront of “toxic” substance litigation for many years. If you believe you or a loved one has suffered an injury as a result of being exposed to a toxic substance of any kind, please do not hesitate to contact us at www.yourlawyer.com for a free consultation.