Pub. date: 2008 | Online Pub. Date: November 27, 2007 | DOI: 10.4135/9781412953948 | Print ISBN: 9781412928168 | Online ISBN: 9781412953948| Publisher:SAGE Publications, Inc.About this encyclopedia
Libby M. Morimoto & Michael A. Kelsh
A biomarker is broadly defined as a substance that can be measured and evaluated as an indicator of normal or pathogenic biologic processes or of a biologic response to a therapy or intervention. In epidemiology, biomarkers are often used to measure internal dose, biologically effective dose, early biologic response, altered structure or function, and susceptibility. By incorporating biomarkers into epidemiologic assessments, researchers may more precisely measure exposures or outcomes, reduce exposure and/or disease misclassification to produce less biased estimates of association, and elucidate biologic processes underlying exposure-disease relationships. The increasing integration of biomarkers in epidemiologic studies has fostered the creation of a distinct multidisciplinary subspecialty called molecular epidemiology in which molecular, cellular, and other biologic measurements are incorporated into cross-sectional, retrospective, and prospective observational studies and clinical trials. Biomarkers may take the form of exogenous compounds (e.g., absorbed chemicals, pesticides, food derivatives, metals), whose presence can be detected and quantified ...