Argumentation Analysis of Risk Assessments: The Case of Perfluorooctanoic Acid.

Risk assessment of chemicals can be based on toxicology and/or epidemiology. The choice of toxicological or epidemiological data can result in different health-based guidance values (HBGVs). Communicating the underlying argumentation is important to explain these differences to the public and policymakers. In this article, we explore the argumentation used to justify the use of toxicological or epidemiological data in the derivation of HBGVs in four different risk assessments for the chemical Perfluorooctanoic acid (PFOA). The pragma-dialectical argumentation theory (PDAT) is hereby applied. The argumentations to select relevant health endpoints or certain studies to infer causality appeared mainly based on "symptomatic relations," that is, study results are used as characteristic of what was claimed to be a causal relation without delving into the actual causal argumentation that preceded it. Starting points that are at the basis of the chain of arguments remained implicit. Argumentation to use epidemiological and/or toxicological data was only briefly mentioned and the underlying argumentative foundation that led to the conclusion was seldom found or not addressed at all. The decision to include/exclude information was made based on the availability of data, or the motives for the choice remained largely unclear. We conclude that more depth in argumentation and a subordinative chain of arguments is needed to better disclose the underlying reasoning leading to a certain health-based guidance value (HBGV). More explicit identification and discussion of starting points could be a valuable addition to general risk assessment frameworks for maximum use of toxicological and epidemiological data and shared conclusions of the assessment.

Changes in skinfold thicknesses and body mass index in 171 children, initially 1 to 5 years of age: a 5 1/2-year follow-up study.

Changes in skinfold thicknesses and BMI were investigated in 171 children aged 1-5 years in 1978 and 5 1/2 years later aged 6-10 years in 1984. Tracking in skinfold thicknesses or body fatness and BMI was determined using the correlation coefficients between these variables in 1978 and 1984. Body fatness tracking was higher in girls than in boys. There were no marked differences between skinfold correlations from sites of the trunk and those from the extremities. Generally, about 50 percent of the variation in skinfold thicknesses in girls aged 6-10 years was associated with skinfold thicknesses 5 1/2 years before. In boys, only about 5 percent of the variation of skinfold thicknesses at ages 6-10 years could be explained by values 5 1/2 years before. There was no marked sex difference in BMI tracking. Initially fatter girls showed higher skinfold thickness tracking than initially leaner girls. Parental fatness level and social class were both related to changes in skinfold thicknesses. Children who became relatively fatter in 5 1/2 years had fatter mothers than children who became relatively leaner. Relatively more children of the lower social class became fatter than children of the higher social class. However, parental fatness level and social class were not in a simple additive way related to changes in skinfold thicknesses.

Bioequivalence of two formulations of piroxicam.

Two separate studies were performed with 12 volunteers in order to demonstrate the bioequivalence of 2 piroxicam (CAS 36322-90-4) tablet and 2 piroxicam suppository formulations after single dose administration. A validated reversed-phase HPLC method with UV-detection is described. Bioequivalence assessment was done by using the posterior probability of a mean ratio between 0.8 and 1.2, and by using the Two One-Sided Tests Procedure (i.e. the 90% confidence interval). The probability approach and the confidence interval approach were compared.