Applied epidemiology for the 21st Century

Background Critics argue that the modem epidemiologist seems more concerned with intricately modelling complex relationships among risk factors than u nderstanding their origins and their implications for public health. Indeed , some contend that epi demiology has reached its limits as a discipline. T o address such concerns, alternatives have been proposed that integrate bio logical, analytical, and social approaches to epidemiological practice and training. Methods The published literature was reviewed to examine critical issues in current epidemiological practice and training. In addition, we reviewed re cords of training programmes in applied epidemiology established in 20 coun tries. Results We describe an existing approach to preparing epidemiologists for t he emerging challenges of public health in which epidemiological research a nd practice are applied toward the end of improving public health and healt h care. Training in applied epidemiology is based on a philosophy of 'learn ing while doing'. Under the supervision of an experienced epidemiologist, t rainees conduct field investigations, analyse large data bases, evaluate su rveillance systems, publish and present scientific research, and respond to public enquiries. More than 3000 people have received intensive formal tra ining over the past 50 years in programmes in more than 20 countries; most graduates continued to use the tools of applied epidemiology in their work. Conclusion Training in applied epidemiology anchors the discipline in popul ation-based, relevant public health practice.