Older people are at risk of developing frailty with advancing age. The prevalence of frailty increases from 2.5-3% in adults aged 65 years to 30-35% in those older than 85 years. These results suggest that an association exists between longevity and frailty. However, at the same time, even at advanced age, the majority of older adults are free of frailty, suggesting that factors different from those contributing to or produced by the life length are involved in producing frailty. Genetic and epigenetic factors, nutrient-sensing systems, mainly the so-called insulin/insulin-like growth factor-1 signaling pathway, mito-chondrial dysfunction, cellular senescence, stem cell exhaustion, inflammation, and some hormonal systems are involved in longevity. However, factors involved in frailty are mainly inflammation and hormones, with an anecdotal role for genetic and other potential factors, but even these two common factors seem to regulate longevity and frailty in different ways. Moreover, their effect on frailty seems to change when they are acting in combination.
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