On May 20, 2020, a study published in the peer-reviewed journal Environmental Health Perspectives has found a consistent pattern of non-monotonic dose-response relationships between exposure to bisphenol A (BPA; CAS 80-05-7) and mammary gland development. Led by a team of researchers from Tufts University in the US, the study took place within the Consortium Linking Academic and Regulatory Insights on Bisphenol-A (CLARITY-BPA) investigating the chemical, which is widely used in the production of resins applied to food contact materials (FCMs). An article published by non-governmental organization Health and Environmental Alliance (HEAL) reviewed some of the key findings from the study and also provided a related question and answer document.

Upon analyzing 91 measurements from rats exposed to BPA, the study found that “both the semiquantitative and the quantitative methods [used] revealed non-monotonic effects of BPA” with the quantitative analysis producing “the most striking non-monotonic dose-response curves.” Across all ages of the rats investigated, lower doses of BPA were found to result in larger effects on the mammary glands, and the study has shown a causal relationship between the low-dose exposure to BPA and the effects observed. These results counter previous statements made in discussions within the consortium that described low-dose effects as rather due to random events.

Natacha Cingotti from HEAL commented that “this study is yet another confirmation that exposure to even low doses of bisphenol A can be harmful to health and that it is not possible to set safe doses of exposure to this widely-used endocrine disruptor. BPA should be fully banned from consumer products and food packaging, and the tolerable daily intake needs to be further reduced.”

CLARITY-BPA was launched in 2013 (FPF reported), and Thomas Zoeller presented on the project’s design and aims at the Food Packaging Forum‘s 2016 workshop.

Read more

HEAL (May 20, 2020). “New scientific study highlights non-monotonic dose-response curves and low-dose effects of bisphenol A.”

HEAL (May 20, 2020). “Questions and Answers on scientific study ‘A combined morphometric and statistical approach to assess non-monotonicity in the developing mammary gland of rats in the CLARITY-BPA study’.” (pdf)

Emma Davies (May 21, 2020). “BPA CLARITY academic study adds to case for low-dose effects.” Chemical Watch

Keller and Heckman LLP (June 5, 2020). “New CLARITY-BPA Study Examines Low Dose Effect.”


Montévil, M. et al. (May 20, 2020). “A Combined Morphometric and Statistical Approach to Assess Nonmonotonicity in the Developing Mammary Gland of Rats in the CLARITY-BPA Study.” Environmental Health Perspectives