Ageing is the shared cause behind diseases we treat one at a time

The argument

Supporters of this research argue that medicine is organised around the wrong unit. Heart disease, stroke, dementia, most cancers, failing kidneys, brittle bones and the general loss of resilience all become dramatically more likely as a person gets older, and each is studied, funded and treated as a separate condition. Proponents argue that this organisation hides what the conditions have in common, which is the biological decline that makes a body susceptible to all of them. The practical consequence, on this account, is a severe limit on what disease-by-disease medicine can achieve. A person saved from one age-related illness remains exposed to the others and commonly dies of the next one within a few years, so successes that look substantial in a single specialism translate into modest gains in how long people stay well. Proponents argue that an intervention acting on the underlying process would instead delay the whole set together, and that this is why they regard the research as a better use of money than another increment against one disease. They also argue that the question is now a scientific one rather than a speculative hope. Ageing in laboratory organisms has been slowed by changes to diet, to particular genes and to known signalling pathways, with the animals living longer and, importantly, remaining healthy for longer; the same mechanisms are present in humans. Proponents accept that translating this to people is uncertain and may fail, and argue that this is an argument for funding careful work rather than for leaving it undone, since the potential return is the prevention of the diseases that account for most illness in later life.

Premises

Counter-arguments

Critics argue that a shared risk factor is not the same as a shared cause, and that grouping very different diseases under one process may be an administrative convenience rather than a biological finding. They point out that results in short-lived laboratory organisms have repeatedly failed to carry over to humans, whose lifespans cannot be studied on the timescales the field needs, and that interventions in animals often work by restricting growth or reproduction in ways no one would accept. The deeper objection is about opportunity cost: money spent on a mechanism that may not exist in humans is money not spent on diseases with known causes and available treatments, and the promise of delaying everything at once has been made before without arriving.

Rejecting the premises

[Rejecting P1] A shared risk factor is not a shared cause, and grouping very different diseases under one process may be an administrative convenience rather than a biological finding. [Rejecting P2] That patients die of a later illness argues for better treatment of each condition as much as for intervening in ageing, and the gains from specialist medicine have been substantial. [Rejecting P3] Results in short-lived laboratory organisms have repeatedly failed to carry over to humans, and the interventions often work by restricting growth or reproduction in ways nobody would accept. [Rejecting C] Money spent on a mechanism that may not be modifiable in humans is money not spent on diseases with known causes and available treatments.