[Fragility in a Public Health perspective: principles and tools for a "life course" approach prevention- oriented]

The increased average life expectancy, not followed by an increase in healthy life years, results in a growing prevalence of frailty, with a significant change in the health needs of the population. Consequently, frailty can be considered an important threat to public health that can be labeled as the future cornerstone of public health. The purpose of this paper is to provide an overview of the concept of frailty that shows how public health language, logic and tools should intervene in the definition of frailty and the related health needs in order to promote a deeper knowledge of the considered condition, its prevention and its management at the individual and population level. Social and environmental determinants of health get a relevant role according to the biopsychosocial definition of frailty. In fact following this approach this condition is reported as multidimensional syndrome. For this reason, different screening and evaluation tools have been developed to investigate the different domains and to allow an early identification of this condition which is essential to help patients in regaining functionality and in the prevention of associated negative outcomes. n addition to these individual assessment systems, from a public health perspective, it is also necessary to have risk stratification tools that can read and evaluate the whole population in order to plan and organize services intended for a community. The characterization of the need for health of the "frail" people does not require a univocal definition that fits all health and social contexts, but rather a sharing among all professionals about the ways to define and recognize frailty according to a multidimensional approach. The training lever represents a qualifying element for Public Health to develop policies, programs and interventions intended for all professional actors involved in the treatment of frailty as well as for patients and their caregivers. The participation of the caregivers and of the community represents a key element for developing adequate responses in a perspective of participatory prevention. Therefore, it is essential that primary care and public health professionals as well organizations act synergically at fragile individual and population level according to a "life-course" and "patient-centered" approach.