I have to say that I think this paper is reaching a little at the edges of the analogy, given some of the very specific and localized conditions associated with smoking, but it is promising to see more research implicitly understanding aging as a process of damage accumulation: "Cigarette smoking reduces life span by an average of 7 years, and tobacco consumption accounts for a shortening of disease free life by 14 years. The exact mechanisms by which smoking causes disease and death are generally not well understood, but evidence continues to mount that cigarette smoking exhausts cellular defense and repair functions, leading to an accumulation of damage e.g. mutations and malfunctioning proteins. In this review, we make an attempt to ascribe many of the deleterious effects of smoking on human health to a general principle, namely the acceleration of aging processes by cigarette smoke chemicals." Smoking is much like maintaining excess body fat - something to cut out of your life if you'd a better chance of living healthily for longer.