Clinical (Therapeutic) Trials

Abstract

>We start by recalling some facts from previous lessons. There, many examples of exposures have appeared such as genetic disposition, smoking, lack of education, poor hygiene, polluted water, crowded housing, malnutrition, use of contaminated needles by drug addicts, and unprotected sex; many more will be treated in later lessons. They all exist independently of the health system. They belong to the first four categories of risk factors listed in Sect. 1.5, namely genetic factors, environmental factors, life style, and social and economic conditions. The study of such risk factors is called “observational” or “analytic” epidemiology because one observes and analyzes already existing situations; see Sect. 15.3. Normally we are of course interested in the influence of factors that make the risk of disease, death etc. increase when their own level increases. Hence as explained in Sect. 2.3 the main application of analytic epidemiology is prevention by lowering the level of risk factors. We might call this “hygiene” in a very broad and modern sense.