In your experience, how often do researchers conducting epidemiology studies using biomonitoring data for exposure assessments consider the half-life of the biomarker?

Answer Explanations

• Never Hardly ever

  Expert 3
   I have not encountered an epidemiologist who considers the half-life of the biomarkers they use. However, my exposure assessment collaborators do take half-lives into account in their studies. 
• Most of the time

  Expert 5
  To be competitive for grant funding etc., a proposal that did not consider the half-life of a chemical in the biological monitoring plan would unlikely be funded.  Although the sample collection procedures may not be ideal (i.e. single spot samples for short lived chemicals) for an epidemiologic study, the investigators should none the less be aware of the limitations of their methods and draw appropriate conclusions.
• Hardly ever

  Expert 4
  Very seldom, most researchers simply used what is available in the data and did not consider the half-life. 
• Hardly ever

  Expert 6
  Metabolism and excretion of the biomarker contribute to within-person variability but are not directly addressed in the paper.
• Most of the time

  Expert 7
  Biomarkers with longer half-lives (e.g., hair, toenails) reduce the impact of short-term fluctuations and better estimate chronic exposure.
  For exposures with known short half-lives, within-person variability is more often a critical factor.
• Sometimes

  Expert 1
  The half-life of the biomarker is a critical component to undertaking exposure assessments in environmental epidemiology. However, not all studies use or determine the half-life when conducting biomonitoring studies. In addition, the analytical methods may differ between studies which makes comparisons of studies difficult. Not assessing the half-life would be a poor quality indicator.
• Almost always

  Expert 9
  This is a fundamental characteristic of the biomarker; I have trouble imagining any researcher ignoring it.  True, there might be little information in the literature about the half-life, and then the researcher might need to consider other options.
• Sometimes

  Expert 8
  Similarly, I would say sometimes, not most of the time. Also strongly depends on the field and type of biomarker. I think in e.g. toxicology, pharmacology, it's more common, but there are various fields using biomarkers and it's not common to report/well known that it is important to all researchers.  Sometimes factors like storage time, storage environment, or time between collection and analysis are taken into account in models. 
• Sometimes

  Expert 2
   This is because while the half-life of a biomarker is a critical factor in accurately interpreting biomonitoring data, it is not always fully accounted for in epidemiological studies. Some studies, especially those with more experienced researchers or where the biomarker's half-life is well understood, do consider it. However, in many cases, this factor might be overlooked or not adequately addressed, particularly in studies with limited resources or a focus on short-term exposure metrics.