New research links drinks cans chemical to heart disease

Tougher restrictions on the use of a chemical used to line food and drink cans will be demanded today following the publication of research linking it to raised heart disease, diabetes and liver abnormalities in adults.

Environmental campaigners have long worried over the presence of bisphenol A (BPA), which 90% of people have at low levels in their bodies.

Evidence from animal studies shows it is an endocrine disruptor which can mimic the naturally occurring hormone estrogen. Critics claim it could potentially interfere with the development of the foetus.

Until now, there has been more speculation than evidence of its effects on humans.

However, research by scientists at Exeter University, published in the Journal of the American Medical Association, one of the world's leading medical journals, has found that adults with higher levels of bisphenol A in their bodies have higher rates of certain diseases.

The study will step up pressure on regulatory bodies to control use of the chemical.

In the same issue of JAMA, two leading US scientists have called for "aggressive action" to limit human exposure, acusing drug regulators in the US and Europe of turning a blind eye to warning signs in animal studies.

The results of the trial will today be put before a committee of the US regulator, the Food and Drug Administration, which is considering what action, if any, needs to be taken.

The research was based on data from the US, collected from the National Health and Nutrition Examination Survey 2003-2004, which included 1,455 adults over 18 and under 74.

The concentration of bisphenol A in the body was measured through a urine sample.

Scientists found that people with cardiovascular disease and diabetes had higher concentrations of bisphenol A in their urine, even when age and sex was taken into consideration.

Those with the highest concentrations of the chemical in their bodies had nearly three times the likelihood of heart disease of those with the least bisphenol A in their urine and 2.4 times the diabetes risk.

People with high levels of chemical also had a higher chance of clinically abnormal levels of three liver enzymes.

The scientists said their study showed a relationship but did not prove that bisphenol A was responsible for the higher disease levels - it is possible there could be some other factor which has not been accounted for.

They have called for more studies to be carried out to confirm what they have found.

Iain Lang, of the epidemiology and public health group of Exeter's Penninsula medical school, said the study was not a reason for people to stop buying canned food or plastic bottles, which are not usually labelled as containing bisphenol A.

"As a scientist, I would say that this is only one study," he said. "I'm not changing my behaviour on the basis of this single study."

Unhealthy habits, such as eating the wrong foods, smoking, drinking to excess and lack of exercise were the main causes of heart disease, he said.

However, regulators would want to reassure themselves that there was no problem, and the FDA and European officials will be under pressure to act.

In a JAMA editorial, Frederick vom Saal, of the University of Missouri, and John Peterson Myers of Environmental Health Sciences, in Charlottesville, Virginia, said the regulators should "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".

Until now, they said, the FDA and the European Food Safety Authority have chosen to ignore warnings in spite of "overwhelming evidence of harm from animal studies".

A contributory factor might be "an aggressive disinformation campaign using techniques ('manufactured doubt') first developed by the lead, vinyl and tobacco industries to challenge the reliability of findings published by independent scientists."

David Coggon, a professor of occupational and environmental medicine at the University of Southampton said that, if the findings were corroborated, there would need to be more controls on exposure to the chemical.

"These are preliminary but potentially important findings," he said. "If low-level BPA were confirmed to cause disease, there would be a need to review controls on sources of exposure to the chemical."

Richard Sharpe, a professor in the Medical Research Council Human Reproductive Sciences unit at Edinburgh University, said it was important to exclude possible alternative causes of the raised heart disease and diabetes levels.

"If you drink lots of high sugar canned drinks you will, over time, increase your risk of cardiovascular diseases and diabetes - I think we already suspect this - and incidentally you will be exposed to more bisphenol A from the can lining.

"In the interests of health protection, it is obviously a priority that we design studies to provide this information before we label bisphenol A as the prime suspect," he said.