No clear-cut connection found between people's exposure to BPA and risk of diabetes in new study of Chinese 40 and older; critics say study group comes from a country with lower BPA levels, should be followed for longer-term effects
September 29, 2011
– People’s exposure to bisphenol A (BPA) and their risk of developing diabetes are not directly connected, according to a study of 3,423 Chinese men and women, ages 40 and up, that was released on Monday, reported Reuters on Sept. 20.
The study, which was published in the Annals of Internal Medicine, did not find a “dose-response” relationship, where the chance of developing diabetes would increase with the level of BPA exposure.
Of those in the study group, 25% with the highest BPA levels had a greater danger of developing diabetes than the 25% with the lowest BPA exposure. However, those with the second-highest BPA levels did not have an increased risk, while those with the second-lowest levels did, Reuters reported.
The study’s conclusions were questioned by some researchers not involved in the study, which was done by a team led by Dr. Guang Ning of Shanghai Jiao-Tong University School of Medicine.
The team treated the data with an “idiosyncratic” approach by essentially ignoring the diabetes risk found with the group with the highest BPA levels, according to an editorial published with the study, reported Reuters.
Limitations of the study include the data not being released for others to review, the low level of BPA exposure of the study group, and the short time in which the group was studied, according to Tamara Galloway, a professor at the University of Exeter in the U.K. and one of the editorial writers.
BPA levels of the group were typically 0.8 nanograms per milliliter, which compares with the U.S. level that is typically nearer to 2 nanograms per milliliter, she said, noting that BPA exposure is also higher in Europe and Japan, compared with China, Reuters reported.
Following the group that was studied for a longer period would have shown if the higher BPA levels led to a greater risk of developing diabetes over time, a question that Ning’s team is now trying to answer by following the same study group.
The team also concurs with critics that more research needs to be done. Galloway said such studies are “crucially needed.”
The primary source of this article is Reuters, London, England, on Sept. 19, 2011.