MODELS OF HUMAN EXPOSURE BASED ON ENVIRONMENTAL MONITORING

The relevant exposure to environmental pollutants or relevant confound ers can virtually never be measured directly in sufficient detail in a sufficient number of people included in an epidemiological study. Ins tead, surrogate indicators of exposure are used that are implicitly or explicitly linked by (conceptual) models to the 'relevant exposure'. Using specified indices (e.g., the coefficient of alienation and forec asting efficiency), the models of different forms can be compared and tested in special investigations. This can evaluate the criterion vali dity of the model through analysis of the agreement between the model estimates, based on measured surrogate indicators of the exposure, and the actual exposure. The perspective on the construct under study may further change the validity of the exposure indicator. Therefore, sub -studies evaluating the quality of exposure indicators should be consi dered as integral part of any study in environmental epidemiology, pre ferably as a pre-study or pilot study.