Australian scientist questions study, findings about BpA in monkey mammary glands

Posted by AFN Staff Writers on 9th May 2012

A new US study, published this week, has found that fetal exposure to the plastic additive bisphenol A, or BpA, alters mammary gland development in primates.

The research appears in the latest Proceedings of the National Academies of Sciences. Hunt and Tufts University School of Medicine researchers Ana Soto and Carlos Sonnenschein co-designed the study with Catherine VandeVoort at the University of California.

BpA is one of the world’s highest production volume chemicals. The global population is exposed to BpA primarily through the packaging of some foods and drinks, but also through drinking water, dental sealants, exposure to the skin and the inhalation of household dust.

These latest findings add to previous studies that suggest the chemical can cause health problems in humans and bolsters concerns about it contributing to breast cancer.

The researchers compared the structure of newborn mammary glands from BpA-exposed and unexposed pregnant female rhesus macaques.

The researchers found that, at birth, the density of mammary buds was significantly increased in BpA-exposed monkeys, and the overall development of the mammary gland was more advanced compared to unexposed monkeys.

Ms Soto said “Because BpA is chemically related to diethylstilbestrol, an estrogen that increased the risk of breast cancer in both rodents and women exposed in the womb, the sum of all these findings strongly suggests that BpA is a breast carcinogen in humans and human exposure to BpA should be curtailed.”

Australian expert comments on latest study’s findings

Dr Ian Musgrave, a senior lecturer in the Discipline of Pharmacology at the University of Adelaide, said the research and its findings are not of concern to the human population.

Dr Musgrave said, “The dosage used was eight times higher than the upper limit of permitted human exposures. It was also administered as a single, large dose which would have produced a much larger concentration in the blood than was seen when the plasma levels were measured four hours later.

“The serum level of total BpA measured at this time were around 50 times higher than is seen in several human studies, but as this plasma level was measured several hours after dosing, the actual exposures would be much higher.”

Dr Musgrave said that the only significant finding was that the number of terminal buds in breast tissue were increased. “This is of doubtful relevance to cancer. No other aspect of breast tissue structure at the gross or microscopic level was changed,” he said.

Although BpA has been banned for some packaging and food containers in 11 US states – most recently in California, the U.S. Food and Drug Administration in March 2012 turned down an environmental group’s petition to ban use of the product but said it would continue research on the health effects.’