Plastic and diabetes, liver ailments linked

WASHINGTON — The first large study of humans exposed to a chemical widely used in everyday plastics has found that people with higher levels of bisphenol A had higher rates of heart disease, diabetes and liver abnormalities.

The research, published Tuesday in the Journal of the American Medical Association by a team of British and American scientists, compared the health status of 1,455 men and women with the level of the chemical, also known as BPA, in their urine.

The researchers divided the subjects into four groups according to their BPA levels and found that those in the quartile with the highest concentrations were nearly three times more likely to have cardiovascular disease than those with the lowest levels, and 2.4 times more likely to have diabetes. Higher BPA levels were also associated with abnormal concentrations of three liver enzymes.

Data on the health status on the study subjects, who ranged in age from 18 to 74 years, were drawn from a large federal database, the National Health and Nutrition Examination Survey, for 2003-2004.

The BPA exposure levels in the study were below those deemed safe by the federal government, adding to a growing body of studies in animals that have linked low-level BPA exposure to various disorders.

"Higher urinary concentrations of BPA were associated with an increased prevalence of cardiovascular disease, diabetes and liver-enzyme abnormalities," wrote the researchers, led by David Melzer, of Peninsula Medical School in Exeter, England. "These findings add to the evidence suggesting adverse effects of low-dose BPA in animals."

The researchers acknowledge the limitations of their work and stressed that follow-up studies are needed to confirm their work and to determine whether BPA caused the observed health problems.

"With human evidence, it will be really difficult for manufacturers to say we really don't think there's any problem," said David Michaels, an epidemiologist who teaches environmental-health policy at the George Washington University School of Public Health and Health Services and the author of a recent book called "Doubt Is Their Product: How Industry's Assault on Science Threatens Your Health."

Despite more than 100 studies by government-funded scientists and university laboratories that have linked BPA exposure to health effects in animals, the FDA has deemed it safe, largely on the basis of two studies funded by the chemical industry.

The FDA controls the compound's use in plastic food containers, bottles, tableware and the plastic linings of canned foods. The agency last month issued a draft report that declared BPA safe for use in food packaging and bottles. The British researchers noted that humans are also exposed BPA through the air and contact with the skin.

Those findings ran counter to a report by another federal agency, the National Toxicology Program, which found "some concern" that BPA might cause developmental problems in the brain and hormonal systems of infants and children.

BPA is ubiquitous in modern life; it is used to give polycarbonate plastic its shatterproof quality and found in everything from water bottles to dental sealants to the linings of canned food and drinks. The chemical can leach into food and liquid; one recent federal study detected BPA in the urine of 93 percent of the population.

Although the human body quickly metabolizes the chemical, it shows up in steady levels in urine and blood, which means humans are constantly exposed to it.

BPA has been in commercial use since the 1950s, and American manufacturers produce about 2 billion pounds annually.

Scientists flagged possible health risks of BPA more than a decade ago. All the industry-funded studies concluded that BPA was safe.

Meanwhile, several major retailers, including Wal-Mart and Toys R Us, have pledged to drop BPA products next year, and some makers of baby bottles and sports bottles have already switched to BPA-free plastic and are heavily marketing their products as safer alternatives.