[Ethical aspects of strategies for prevention].

Prevention must be offered actively to all sections of the target population. The spontaneous process select people at lower risk. The active offer of preventive measures must be modulated on the difficulty to be reached of the different sections of the target population. The main problem of prevention is that the risk factors of non compliance are the same for a higher incidence or prevalence of events or conditions. The efficacy of a preventive strategy is valuable observing a reduction of the incidence or prevalence of preventable events or conditions in a definite period of time and in a defined community. In the case of prevention ethical and professional quality coincide.