The interrelationship between disease and ageing and the implications for longevity

Ageing is generally viewed as a detrimental phenotype; with age comes increasing susceptibility to disease and frailty. Recent data also suggests that disease can result in an increase in ageing phenotypes suggesting a positive feedback loop. It is clear that lifespan can be modified genetically and by interventions in certain organisms but the mechanisms by which this is achieved have not yet been fully elucidated, as indeed is the case for the ageing process itself. Because of the intimate relationship between disease, ageing and ultimately lifespan it is difficult to dissect the effects of individual changes. As we learn more about individual pathways and allelic variants influencing ageing and disease we can begin to unravel the influence of natural selection on these processes.