Plastic bottle chemical linked to heart disease
Exposure to a compound commonly found in plastic food containers is linked to heart disease and type 2 diabetes, according to the first large epidemiological study in humans.
The findings come just as the controversy surrounding the chemical, bisphenol A, is hotting up, with two US government bodies issuing conflicting advice about its safety.
BPA is used in the coatings that line food tins, in the hard clear plastics that make baby bottles and in dental sealants. More than 2 million tonnes are produced worldwide every year,
and over 93% of Americans have evidence of exposure in their urine.
But most studies investigating potential dangers have been done in animals, which metabolise the chemical more slowly than humans, raising questions about how reliable such findings
In the new study, however, Tamara Galloway at the University of Exeter, UK, and her colleagues analysed data from 1455 human adults studied as part of the National Health and Nutrition
Examination Survey (NHANES) conducted in 2003 and 2004.
The researchers looked at whether there was an association between urinary BPA concentrations and certain diseases.
The researchers found that, after adjusting for age and sex, concentrations of BPA were higher in people with cardiovascular disease and type 2 diabetes. People with the most BPA
exposure were three times as likely to have cardiovascular disease, and 2.4 times as likely to have diabetes, as those with the lowest levels
“This is just a snapshot,” says Galloway, who says it gives an indication of exposure in the week before the sample was given. The findings cannot prove causality. “Now we want to know
what happens over time.”
Nira Ben-Jonathan, at the University of Cincinnati, who has studied BPA for over 12 years, was impressed with the
She has looked at how BPA affects human fat tissue, and found that it suppresses adiponectin, a hormone that regulates insulin sensitivity. This suppression would predispose a person to
diabetes. Galloway’s research, Ben-Jonathan says, complements her own.
Csaba Leranth, at Yale University in New Haven, Connecticut, whose group did the first study of BPA in primates,
says a human study was much needed. “I find the data very convincing,” he says.
This research will help inform the policy of the US Food and Drug Administration, which held a public hearing into the chemical on 16 September, at which the paper was presented. Last
month, the FDA issued a draft report saying current exposures of the chemical posed no danger.
Just a few weeks later, however, the National Toxicology Program, a government-funded body charged with providing unbiased, scientifically sound evaluations of available evidence,
issued its final report on the chemical. This concluded that current human exposure levels were cause for concern.
“Changes are happening at doses most humans are exposed to,” says John Bucher, NTP Associate Director.
Anila Jacob, at the Environmental Working Group, a non-profit organisation based in Washington, DC, says the discrepancy between the two bodies is due to how they chose to weigh the
The FDA, she says, relied entirely on three industry-funded studies, because they followed certain procedural rules. “The FDA discounted scores of independent studies by academic labs,”
she says. The NTP included these if they had merit.
The new paper, says Sarah Vogel, at the Chemical Heritage Foundation in Philadelphia, is going to be important because it is confirming effects that are seen in the laboratory. “Yes, we
can rely on these animal models,” she says. “We shouldn’t be waiting for decades to pass for unequivocal epidemiological studies before we act.”
by Alison Motluk
Journal reference: Journal of the American Medical Association (vol 300, p 1303)