On damage accumulation and biological aging

Abstract

If biological aging is understood as some process of damage accumulation, it does not necessarily lead to increasing mortality rate. Within the framework of suggested models and relevant examples we show that even for the monotonically increasing degradation, the mortality rate can, at least, ultimately decrease. Aging properties of systems with imperfect repair are also studied. It is shown that for some models of imperfect repair the corresponding age process is monotone and stable. This means that as ∞ → t , degradation slows down, which results in the mortality rate deceleration and its possible convergence to a constant.

Age trajectories of physiological indices in relation to healthy life course

“…Other approaches can be applied in different circumstances depending on availability of additional information apart from data on incidence of diseases. For example, the (random) vitality or a first-passage type models (Arbeev et al, 2005; Finkelstein, 2007; 2009; Li and Anderson, 2009; Strehler and Mildvan, 1960) can be employed to investigate the shapes of the incidence rate curves. The availability of individual data on minor health deficits and symptoms collected in surveys allows for construction of a cumulative measure of health deterioration called a frailty index or an index of cumulative deficits (Goggins et al, 2005; Kulminski et al, 2007; Kulminski et al, 2008b; Kulminski et al, 2008c; Mitnitski et al, 2001; Rockwood and Mitnitski, 2007; Yashin et al, 2007b; c) which proved to be an efficient empirical approach to investigate aging related processes of health deterioration.…”

Reliability aspects in a dynamic time-to-failure degradation-based model

“…The influence of a degradation model on the lifetime distribution can be evaluated by the aging behavior that the degradation model exerts on the lifetime distribution. Finkelstein 9 provided some perspectives for aging process under a given degradation model. Li et al 10 conducted the study of preservation of several aging properties and showed that for simple additive degradation models with a single random effect, the aging property of the random variation and the shape of the mean degradation path affect the aging behavior of the implied lifetime distribution.…”