Frailty and vulnerability: Are the two terms equivalent in paediatrics and geriatrics?

The recent medical literature has been using the term vulnerability to refer to harm to human integrity. The concept is multifaceted. Bioethics researchers conceive vulnerability as one of the basic anthropological features of the human condition. On the other hand, some bioethics scholars advocate using the terms susceptibility or variable vulnerability to refer to diseased or destitute populations. Also, frailty and variable vulnerability are correlated but not equivalent conditions which have been described somehow interchangeably in the recent medical literature, especially in the study of the ageing phenomena. The extremes of age are especially vulnerable periods of life and there has been growing evidence that neonatal and early life events have long-term influence on both the ageing process and frailty. This paper discusses some issues relevant to vulnerability and frailty and how one could possibly distinguish between them. There is still much to be learned about how frailty and variable vulnerability affect the ageing process across the life span.