Senescence and pathology in ageing

The life expectancy of people living in the UK has been extended over the last century due to changes in the principal causes of death. Nowadays, people are more likely to die of diseases related to the ageing process rather than the infectious diseases which hitherto were more common causes of death in younger people. Ageing is associated with the degeneration of functional capacity in all parts of the body, and at all levels of organisation from molecules to complete organ systems. These functional changes are referred to as senescence. Both genetic and environmental factors govern senescence, although the precise mechanisms and the extent of their involvement are largely unknown. Senescence changes may themselves be responsible for certain diseases and disabilities associated with old age, or they may be a contributory factor and increase a person's susceptibility to particular diseases. The latter is the case with the most commonly encountered causes of morbidity and mortality today, namely atherosclerosis and cancer.