In this document we present the different steps used to pre-treat the biomarker data in Sepages. To date this process has been applied to pregnancy urinary levels of phenols and phthalates and cytokine data. This process includes mainly:

  • imputation of data below the different detection limits using the fill-in method (Helsel 1990)
  • correction for protocol variables using the method presented in (Mortamais et al. 2012)

We will use the example of the Sepages pregnancy phenols data.

Here is an overview of the process and the different variables created:

Figure 0.1: Sepages data preprocess flow-chart