Any factor, whether event, characteristic, or other definable entity, that brings about change in a health condition, or in other defined characteristics
Cornell University, Department Neurobiology and Behavior, Course: Clinical Neurobiology, Glossary of Epidemiological Terms, New York, USA 2012. https://courses.cit.cornell.edu/bionb4280/Epidemio logy%20Terms.pdf, (Dzstr Prep/ Epid - Amer) {1004}