Risk to all or none? A comparative analysis of controversies in the health risk assessment of Bisphenol A.

Bisphenol A (BPA) is an endocrine disruptor for which health risk assessment has proven controversial. Conclusions regarding health risks of BPA vary between assessments from "there is no risk to any part of the population" to "there is risk to the entire population". We have carried out a literature study investigating what might be the scientific and/or policy-related reasons for these differences. Ten risk assessments for BPA were scrutinized and several factors were compared between assessments, including estimations of exposure levels, identification of critical study and NOAEL, assessment factors and significance attributed to reports of low-dose effects. Differences in conclusions were mainly influenced by the evaluation of low-dose effects and the uncertainties surrounding the significance of these data for health risk assessment. The results illustrate the impact of differences in risk assessment policy and expert judgment on the risk assessment process and highlight the importance of transparency in this process.