Age-related diseases have long been thought of as inevitable, natural consequences of getting older. The traditional medical response to age related diseases such as cancer has been to detect and treat them as early as possible, to cure if possible and reduce suffering and prolong life when an illness cannot be cured. These are important and valuable approaches but in an ideal world, the best approach is always prevention.
Preventative veterinary medicine has been incredibly effective at reducing the burden of infectious disease, parasitism, malnutrition, injuries, and many other causes of suffering and death in dogs. However, the options are limited for preventing the many diseases of aging. Maintaining a healthy body weight, regular exercise, and a few other lifestyle interventions do reduce risks to some extent, but we need to turn our growing understanding of the mechanisms of aging into therapies that address aging itself.
The direct way to accomplish this is through interventions that prevent or delay the occurrence of specific age-associated diseases. If targeting particular mechanisms of aging can reduce the chances of our dogs developing cancer, for example, this would prolong life and preserve health for many individuals because cancer is a leading cause of death in aged dogs.
However, the immediate cause of death for most dogs is not any specific disease but rather euthanasia. We choose to let our dogs go when it is clear that they are experiencing significant suffering or loss in quality of life.
Aging also leads to a general loss of comfort, function, and resilience, a condition known as frailty. One of the greatest potential benefits of targeting the underlying mechanisms of aging would be to slow the onset of frailty. Keeping dogs biologically younger for longer evwould extend healthspan and could also indirectly lengthen life by delaying the point at which quality of life has declined so much that euthanasia is necessary.
Immortality, of course, seems unlikely for complex biological organisms, and fatal illness or unacceptable frailty is likely inevitable for all dogs eventually. However, there is great potential to improve overall quality of life by compressing the period of significant disease and disability to as small a fraction of the lifecycle as possible and extend those prime, healthy years.