In one of the latest shots fired in the war of words raging over the safety of bisphenol A (BPA), a new study has linked elevated concentrations of the chemical in human urine to increased risk of cardiovascular disease and diabetes.
BPA is an industrial chemical used primarily to make polycarbonate plastic and epoxy resins. It was first synthesized in 1905 and has been in common use since the 1950s. It is used in the production of food containers, water and baby bottles, eyeglass lenses, CDs and DVDs, cell phones, and countless other products.
“Using data representative of the adult US population, we found that higher urinary concentrations of BPA were associated with an increased prevalence of cardiovascular disease, diabetes, and liver-enzyme abnormalities,” a group of U.S. and British researchers reported in a study published in September in the Journal of the American Medical Association (JAMA).
“These findings add to the evidence suggesting adverse effects of low-dose BPA in animals,” the researchers said, adding that independent replication and follow-up studies are needed to confirm their findings and establish a cause and effect relationship.
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Plastics manufacturers and the chemical industry have steadfastly defended the safety of BPA. The Bisphenol A Global Industry Group states that “the potential human exposure to BPA from polycarbonate plastic and epoxy resin food contact applications is minimal and poses no known risk to human health.” The group based its conclusion on three main points:
- BPA is not carcinogenic and does not selectively affect reproduction or development. The No-Observed-Adverse-Effect-Level (NOAEL) for BPA, confirmed in multiple laboratory animal tests, is 50 mg/kg body weight/day;
- The estimated dietary intake of BPA from polycarbonate plastic and epoxy resin food contact applications, based on the results of multiple migration studies with consistent results, is less than 0.000118 mg/kg body weight/day; and
- This potential human exposure to BPA is more than 400 times lower than the maximum acceptable or “reference” dose for BPA of 0.05 mg/kg body weight/day established by the U.S. Environmental Protection Agency, which is derived from the NOAEL.
But industry assurances have been undermined by recent research that has raised serious questions about the safety of BPA. The Washington Post reports that some studies have linked the chemical to prostate and breast cancers, diabetes, behavioral disorders such as hyperactivity, and reproductive problems in laboratory animals.
Several consumer and environmental watchdog groups warn constituents of the dangers of BPA, and they advocate the use of alternative containers and products that do not contain the chemical.
However, a draft assessment released by the federal Food and Drug Administration (FDA) in August found that exposure to the small amounts of BPA that migrate from containers into the food they hold are not dangerous to infants or adults.
“FDA concludes that an adequate margin of safety exists for BPA at current levels of exposure from food contact uses, for infants and adults,” the assessment stated.
The report was welcomed by the industry-sponsored bisphenol-A.org website, which stated that: “The findings of the draft FDA assessment are consistent with and further support the conclusions of many earlier evaluations that bisphenol A is not a risk to human health at the low levels to which people might be exposed.”
But almost before the industry could finish celebrating, the National Toxicology Program (NTP), an offshoot of the National Institutes of Health (NIH), released a report stating that current human exposure to BPA “is of ‘some concern’ for effects on development of the prostate gland and brain and for behavioral effects in fetuses, infants and children.”
“We have concluded that the possibility that BPA may affect human development cannot be dismissed,” said NTP Associate Director John Bucher.
Heard the hype about bisphenol A (BPA)? Wondering whether you should be doing anything to protect your workers? Find out at BLR’s November 10 audio conference. Can’t attend? Pre-order the CD. Satisfaction assured.
The NTP report was followed in short order by the JAMA study linking higher urinary concentrations of BPA to increased risk of cardiovascular disease and diabetes. That study’s findings were attacked by the American Chemistry Council, which said the study had inherent limitations which made it incapable of establishing a cause and effect relationship between BPA and the cited health effects.
Both sides agree that follow-up studies are needed.
So what does it all mean? Tomorrow we’ll look at workplace exposures to BPA, and at an upcoming audio conference that will help you make sense of the debate, and steps you can – and should – take to safeguard your workers.