Frailty, the determinants of health and the new evidence base

Frailty, a consequence of cumulative decline in many physiological systems during a lifetime, is a state of vulnerability to poor resolution of homoeostasis after a stressor event.1 A popular operationalization sees frailty in relation to deficits (i.e, symptoms, signs, diseases, and disabilities) that accumulate with age.2 At a given point in time, a person's health may be quantified as a frailty index (FI), which is the ratio of the deficits...