Genetic epidemiology is a relatively new medical discipline that seeks to understand how genetic factors interact with the environment in the context of disease in populations. Areas of study include the causes of inherited disease and its distribution and control.
Genetic epidemiology... It's a relatively new field. Epidemiology itself is not. Epidemiology refers in general to the study of populations and characteristics of populations, but the addition of genetic to the word epidemiology in recent years connotes the influence that genetic factors have on disease incidence or other traits that characterize individuals in a population, whether those are people or other individuals in a population; most often people. Importantly, because what we're studying in genetic epidemiology is people in an environment, what one observes in genetic epidemiology is not simply the genetic characteristics of the individuals across the population, but also the environmental influences that those populations are subject to in the area in which they live.