The principle of population medicine is to shift our concentration away from the pathophysiologic effects of disease on individuals, and refocus it on a much bigger question, what connection will you and your patients have with the health of the public? In population medicine, we will use the young population, active population and elderly population but particularly elderly population is chosen as a model population to explore the intersection between clinical practice and population medicine. In general, the population-based medicine contains the elements needed to direct constructive and positive change and evolution in health care systems. The importance of this for population-based perspective is that internal medicine is believed to hold the power of decision making in present day health care systems. Efforts to promote population-based approaches to medicine will require several facets: the development of more complete, comprehensive, convincing and accepted models or paradigms of care; educational influences on the various levels of care personnel, on those who control decisions about the organization of care, and care users; institutional support for those developing population-based approaches, those teaching population-based approaches, and those using them in clinical medicine and in the development of policies and programs meant to serve the needs of the population. And the interface between those principally engaged in the development of the approach and those who use it but do not principally develop it. In regard to the processes necessary for implementation of population-based approaches, all those involved in the health care system must engage in critical thought of the types i.e., they need to understand the rules of evidence in the five kinds of studies identified as need, efficacy, efficiency, effectiveness, and availability. The population-based perspective is a dimension of research in which other dimensions are service and education. It is a dimension of education in which there are dimensions of institutional continuity and of the processes of education. It is a dimension of service in which there are also policy and management decisions. Clearly, population-based perspectives rest on a set of assessments -- assessments of the needs of populations, both in their own terms and in the terms of those concerned with prevention. In addition to including the content issues of measurement, sources of error, and a population base, effective education in population-based medicine must be relevant.

Doctors took care of their patients one visit at a time. Rarely did they think compelled to pay much more attention to the bigger communities to which their patients belonged. That was left to public health professionals, if they existed. In more recent times, however, it is become abundantly clear that practicing high quality, cost-effective medicine requires us to look beyond our patients to see a whole population of people in need of our attention. Moreover, in population medicine the optimal health and productivity of animal populations, ensuring the safety of foods of animal origin and preventing animal-related disease in humans are discussed.

There are many objectives of population medicine but some objectives are as follows:

-to discover the population-based determinants as well as characteristics of health and explain how they interact to predispose patients to a range of health outcomes.

-to put clinical medicine and the patients it serves in their proper biologic, demographic, economic and social context.

-to differentiate between clinical approaches that target the same health outcomes.

-to utilize preventive medicine to point up the clinical application of population medicine.

-to illustrate how population medicine can be employed to clinical practice using the elderly as a potentially vulnerable and susceptible population.

-to demonstrate the attitudes and skills necessary to professionally interact with elderly individuals in their places of residence and develop a clinical plan to intervene on their behalf.

-to propose pragmatic and practical strategies for solving complex clinical problems in geriatrics using both population and clinical interventions.