Consider the many causes of death that may not be strongly negatively correlated with the particular metrics being targeted here, like accidents, heart disease,

Consider the many causes of death that may not be strongly negatively correlated with the particular metrics being targeted here, like accidents, heart disease, or stroke. An improved immune system response (aimed at infectious diseases) may also do well at suppressing cancer rates (2nd leading cause of death), or if not, may at least improve remission or survival rates for treatments, but that is somewhat speculative, and you might also (or instead) get an increase in various autoimmune problems. So, from a "reversal" of a decade or more of aging by those measures, you might find that longevity is only increased by a couple of years.