Challenges to retrospective exposure assessment

Retrospective exposure assessment has become a crucial component in the int erpretation of occupational epidemiologic results. Many advances have been made over the last 2 decades, but substantial progress is still necessary t o reduce the misclassification of exposure. The efforts needed include eval uating the validity and reliability of assessment methods, better documenta tion of the methods, use of exposure determinants to estimate exposure leve ls more accurately and reliably, and an increase in the understanding of in dustrial hygiene and biological measurement data and questionnaires, their limitations, and how to use them best. In addition, better characterization of exposures is necessary. This need includes evaluating dermal and ingest ion hazards, incorporating nonoccupational sources of exposures, particular ly hobbies, evaluating the effect of multiple chemicals, and exploring diff erent exposure metrics.