Public health epidemiology.

Clinical epidemiology versus public health epidemiology Epidemiology is growing, and so is the need for developing subspecialties. One subspecialty which has achieved a certain prominence is clinical epidemiology. The term had already been coined in 1938,1 and although it has many different interpretations,2 the growing number of textbooks providing an introduction to the area shows that it has become firmly rooted, both within epidemiology and within clinical medicine.5 According to Feinstein, "clinical epidemiology is concerned with studying groups of people to achieve the background evidence needed for clinical decisions in patient care".5 Where does that leave the rest of epidemiology? Historically , epidemiology has always been closely connected to public health, and a lot of epidemiological work still implicitly or explicitly aims at informing public health decisions. The title of the Journal of Epidemiology and Community Health is a clear illustration of this link-and of the difficulties which public health practitioners and researchers have encountered in sticking to one name for their field of work. According to a recent and widely used definition, public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts of society".6 It is the health of communities, not of individual patients, which is being served by public health practitioners. Public health interventions usually have a collective, society-wide character .7'8 The time has come for the oldest subspecialty in epidemiology to carry its own name-public health epidemiology. It is the branch of epidemiology which, in the short or long term, aims to inform public health decisions. Public health epidemiology encompasses a wide variety of study areas: much of the work which is currently being done under the headings ofinfectious disease epidemiology, social epidemiology, occupational epidemiology, environmental epidemiology, and nutritional epidemiology, for example, is highly relevant to public health, and it is quite obvious that epidemiologists working in these areas will feel the need to organise themselves in "sub-subspecialties". Nevertheless, the umbrella of public health epidemiology also needs to be asserted, and it is therefore to be welcomed that the European Public Health Association has decided to establish a Public Health Epidemiology Section. The distinctive features of public health epidemiology One way of testing the usefulness of a subspecialty labelled public health epidemiology is to ask whether it needs its own (postgraduate level) textbook. If public health epidemiologists could learn their trade from the available introductions to general epidemiology …