Mathematical modeling of the aging processes and the mechanisms of mortality: paramount role of heterogeneity

Main problems of modeling the link between aging processes and mechanisms o f mortality are addressed. Various applications of Gompertz's law, which al lowed to formulate some fruitful hypotheses on the field, are reviewed. Som e pitfalls occurring in its applications are also discussed using a model b uilt on purpose to overcome these difficulties. The role played by heteroge neity emerges as the common cause of some relevant failure in using Gompert z's law and the necessary key ingredient of any model aimed to interpret th e link between aging and mortality correctly. Though a number of problems a re related to inter-individual variability, the search for their solution c an lead to an intriguing approach to the study of aging and mortality. Livi ng beings can be considered as complex systems and their age-related change s can be described at the light of complex system theory. (C) 2001 Elsevier Science Inc. All rights reserved.