SAGE KE Bulletin Board
what is and is not right to call "anti-aging medicine"?
3 July 2002
Aubrey D de Grey
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.
Aubrey de Grey
Science of Aging Knowledge Environment. ISSN 1539-6150