Design of studies for validation of biomarkers of exposure and their effective use in environmental epidemiology

Studies in environmental epidemiology suffer from the problem that precise assessment of relevant exposures is difficult to undertake, in particular on an individual level. There is much hope that biomarkers may help to move to much more specific studies. However, a variety of issues on the role of biomarkers and their validity need to be clarified beforehand. This paper summarizes issues of the design of studies for validation of biomarkers. Emphasis must be on collecting concurrent information on external dose and related biomarker status (internal dose) for individual subjects.