ABSTRACT
Age-related diseases are diverse and affect different systems. It is therefore striking that they share a common pattern in their incidence curves. Removing senescent cells should similarly reduce the incidence of all age-related diseases. The susceptible fraction stems from the notion of population heterogeneity in the fields of epidemiology and genetics. The incidence curves of most cancer types show the familiar exponential rise with age and drop at very old ages. In many infectious diseases, mortality rate rises exponentially with age. Stem cells and differentiated cells are both exposed to damage, such as air particles, pathogens, and the mechanical stress of breathing. The chapter considers an age-related disease in which the lungs fail, called Idiopathic Pulmonary Fibrosis (IPF). Senescent cells affect proliferation and removal in a way that pushes them toward the threshold. Susceptibility to osteoarthritis, as in IPF, is due to genetic and environmental factors.
