Epidemiology as a discipline originated in the search for causes of outbreaks and epidemics of communicable diseases with the aim of fi nding effective ways of preventing and controlling them [1]. A disease can be effectively prevented only after its causes or risk factors are known. Epidemiological research is thus the prerequisite for prevention, and epidemiology forms a core discipline of public health, a modern and broader version of preventive medicine. However, public health deals with health issues at the population or societal level as opposed to clinical medicine that works at the individual level. Epidemiology that is used to study and understand health issues in populations thus forms the foundation for public health, and has long been known as a discipline relevant only to public health.