British scientists have revealed a possible link between the chemical bisphenol A (BPA) and disease in adults.

A research team from the Peninsula Medical School, the University of Exeter, the University of Plymouth and the University of Iowa, have found evidence linking bisphenol A to diabetes and heart disease in adults

BPA is a controversial chemical which has hit the headlines in recent years over suspected health risks, particularly to babies.

BPA is used in polycarbonate plastic products and commonly used in food and drink containers such as refillable drinks containers, compact disks, some plastic eating utensils, some baby's bottles and many other products in everyday use.

It is one of the world's highest production volume chemicals, with over 2.2 million tonnes (6.4 billion pounds) produced in 2003, with an annual growth in demand of between 6-10% each year.

While some research in animals has suggested that BPA is safe, some laboratory studies have raised doubts, as experiments in which mice and rats were exposed to BPA have shown that higher doses of the chemical can lead to liver damage, insulin resistance, diabetes and obesity.

The laboratory animal evidence to date, is complicated and controversial, but nevertheless some scientists believe that BPA can disrupt hormone levels, especially oestrogen, and they suggest that the full biological effects of BPA in humans is far from clear.

The researchers looked at information from the U.S. government's National Health and Nutrition Examination Survey (NHANES) 2003-2004, the only large-scale data available on BPA concentrations excreted in urine.

They analysed the results for the 1455 adults aged between 18 and 74 years old for whom measures were available - a group representative of the general population of the USA.

Their analysis found that the 25% of the population with the highest BPA levels were more than twice as likely to have heart disease and/or diabetes, compared to the 25% with the lowest BPA levels and higher BPA levels were also associated with clinically abnormal liver enzyme concentrations.

This is the first time that evidence has emerged of the association between higher BPA levels and disease in adults.

The scientists say while their study has identified a statistical association between BPA and adult diseases for the first time, much more research is needed to exclude the small possibility that the association is due to some other unstudied factor, or that people with these diseases somehow become more exposed to BPA - they say it is also unclear whether the liver enzyme changes are linked to liver damage.

Professor David Melzer, Professor of Epidemiology and Public Health at the Peninsula Medical School, who led the study, says it has revealed, for the first time, an association between raised BPA loads and two common diseases in adults but it remains unclear if BPA is the direct cause of the extra cases of heart disease and diabetes - but if it is, some cases of these serious conditions could be prevented by reducing BPA exposure.

Professor Melzer says that this new possible link does not detract from the existing health advice to people on how to prevent heart disease and diabetes.

The research was published in the Journal of the American Medical Association.