what is and is not right to call "anti-aging medicine"?
Since the publication in recent months of a number of consensus
statements on the general topic of anti-aging medicine, with the
composition of some of which I was involved, it has become clear
that the inconsistent use of the term "anti-aging medicine" is a
severe barrier to communication and hence progress in this area.
I would thus like to propose a first step in resolving this. In
a bid to establish some coherence in the discussion, I'm posting
this to several fora on which the issue has been raised recently:
- the SAGE KE bulletin board
http://sageke.sciencemag.org/cgi/eletters?lookup=by_date&days=60
- the dEbate concerning Science 296:656
http://www.sciencemag.org/cgi/eletters/296/5568/656a
- sci.life-extension
http://groups.google.com/groups?group=sci.life-extension
and I encourage responders to do likewise. I'd also hoped to post
to the AARP discussion of the recent Scientific American articles,
but that thread seems to have been discontinued.
The nub of the issue is that there are two senses in which a given
intervention can lay informal claim to the description "anti-aging
medicine": one is that it appreciably reduces age-specific death
rates in the elderly, and the other is that it appreciably reduces
age-specific frailty in the elderly. We can therefore distinguish
three broad subclasses of anti-aging medicine as thus (informally)
defined:
1) Apocalyptic anti-aging medicine (AAAM): medicine that lengthens
lifespan but not healthspan appreciably, and thereby increases the
proportion of life that is spent in infirmity.
2) Makebelieve anti-aging medicine (MAAM): medicine that lengthens
healthspan but not lifespan appreciably, and thereby decreases the
proportion of life that is spent in infirmity -- great -- but also,
potentially, deludes the patient into the assumption that they are
also raising their life expectancy just because they feel fitter.
3) Proper anti-aging medicine (PAAM): medicine that lengthens both
healthspan and lifespan, by comparable (appreciable) amounts.
There is very broad agreement among gerontologists that AAAM is not
only undesirable but infeasible, simply because being frail is risky.
It is a major scandal that prominent commentators (such as, recently,
Francis Fukuyama) persist in expounding the fiction that AAAM is a
rather likely outcome of anti-aging research; this assertion must be
challenged by experts with much more vigour than it has been lately.
However, for present purposes I believe that it can simply be left
out of the discussion on account of its agreed infeasibility.
There is considerably less agreement about the relative feasibility
of MAAM and PAAM. This is something that will only be resolved by
future progress (or, I suppose, lack of it). A realistic short-term
goal, however, may be to achieve a broad consensus regarding which of
these two categories (or subsets of them) are appropriately included
under the umbrella term "anti-aging medicine" and which are not. It
was for this reason that I stressed above the informal nature of the
definition of "anti-aging medicine" that I was subdividing.
I am aware of three distinct schools of thought about this:
A) Anti-aging medicine rightly covers both MAAM and PAAM. This view
has recently been expressed by Tom Matthews on a couple of the
lists where I'm posting this.
B) Anti-aging medicine rightly covers PAAM but not MAAM. This is my
view.
C) Anti-aging medicine rightly covers only a subset of PAAM, namely
medicine that decreases age-specific mortality by progressively
greater amounts at greater ages (a stretch of the survival curve
rather than a right shift), and not MAAM. This is the view that
Jay Olshansky has expressed to me.
By way of getting a discussion rolling on this, I will summarise my
reasons for preferring (B) above. Ultimately my view is based on my
opinion about the present and foreseeable existence of PAAM, which is
that it does not exist at all yet but is eminently foreseeable. This
is intermediate between two views that are much more widely held by
the public: the overoptimistic view that PAAM is already available,
at least in modest form, and the overpessimistic view that PAAM has
essentially no chance of being developed in the lifetime of anyone
currently alive. Using the same term for MAAM and PAAM reinforces
both the overoptimistic and the overpessimistic views: the optimist
forgets that PAAM is very much not yet available, and the pessimist
forgets that PAAM is worth thinking about at all.
It has been suggested that efforts to adjust the accepted meaning of
established terms will only confuse people. I agree, but only when the
term is indeed established with an accepted meaning. Plainly this is
not the case for "anti-aging medicine", so I feel that it's worthwhile
to try to improve agreement on what that term should and should not be
used to encompass.
-You start out so objectively and then you totally destroy your credibility with
these clearly biased definitions.
The result is that no further rational and objective discussion is possible.
-COMMENT:
Let's start with this category. As a practicing geriatrician I used to have
patients ask me to give them what you call MAAM-- they said they didn't want
anything that would prolong their lives, but they wanted to be healthier
while they lived. I told them soberly that what they were asking me for
generally not possible, inasmuch as it's harder for any particular cause to
kill somebody whose overall health status is better to begin with. The only
exceptions derive from really overwhelming causes of mortality like sudden
idiopathic ventricular fibrillation, and if I knew a patient who was at risk
for something like that, I could legitimately deliver MAAM by deliberately
failing to do anything preventive about what was likely to be the cause of
sudden death (no implantable defibrilators, no Amrinone), while at the same
time delivering other kinds of prevention. So the patient at risk for sudden
V-fib would still get the mammograms and the antihypertensives and the
exercise program, with the understanding that they'd probably feel great
until the day they fell face forward into the soup.
This kind of opportunity is very rare, because there aren't that many things
which can be counted on to kill without prior disability, like heart
dysrhrythmias. While it's quite possible to identify beforehand what is
probably going to be your patient's weakest system (they have very high
blood pressure or cholesterol or a bad family history of cancer or dementia
or whatever), the fact is that most of the suffering and the really long
periods of disability in medicine are usually seen in people who develop
some particular severe problem early in life in just one organ system, while
retaining a good portion of vitality in all the others. The weak organ
system causes the disability and suffering,but the others keep the patient
from going all the way to death. This happens by definition always in
non-elderly patients (since very old people universally have multiple organ
reserve function loss). And if you do anything about it (the weak organ
system) you're going to lengthen life span proportionately with health span,
because the guy you prevent from being a cardiac cripple is also the guy you
prevent from dying of the MI.
In geriatrics, what is generally termed "frailty" is loss of reserve in
multiple organ systems, such that at some point a severe illness of any
kind, or any stressor, is likely to bring down the whole thing, like a house
of cards. The art of geriatrics lies in keep the patient functional and
alive as aging causes frailty, but without too much disability (again,
severe long term disability usually results from one system progressing
faster than the others in dysfunction), until you reach the overall frailty
point where any major illness will result in multiple decompensation
cascades, and rapid death. But you can't get to this point with anything
resembling MAAM.
Again, I believe that in the absence of a very specific problem (a berry
aneurysm, say) that will kill fast and early if untreated, and which you do
not or cannot treat-- while at the same time, doing everything else to
maintain the patient's health, MAAM is not possible. MAAM is getting your
prisoners on death row to exercise, eat right, and have colonoscopy. In the
real world, forget it.