Framing an Aging Intervention (reflections 2)

 

For many years now I have been a proactive champion of the scientific field of study that I think will have the most significant impact on the health and economic prospects of humanity this century- “geroscience” and an applied gerontological intervention that retards the rate of molecular and cellular decline.  

And a great deal of my research has focused on the societal challenges of framing, and prioritizing, this area of science when most people do not even perceive the harms of senescence as a public health problem, are mostly ignorant about the biology of aging and are unaware of the recent scientific discoveries in altering the rate of aging. 

What is worse than indifference to this area of scientific research is the open hostility and opposition people (even eminent "public intellectuals") often have towards it.  And this blog post addresses this concern by noting that much hinges on how one “frames” the moral imperative to alter aging.

        To cut the chase, the wrong question to ask, in my opinion, is to ask- “Should we pursue life extension?”  This is the wrong question to ask because it is ambiguous, and thus it is likely to be prone to skewed moral evaluations of the stakes involved with “extending life”.  For example, some might interpret this question as asking them if they would want to life forever, to be immortal.  Others might, reasonably, infer the question implies an extension of the period of frailty, disease and disability at the end of life by delaying death for as long as possible.

        Because the aspiration of “life extension” lacks precision, talk of “life extension” typically raises a wide array of intuition-based concerns, such as whether we would be bored living hundreds of centuries, or how this would likely impact the global population size and environment, etc., or if this would create a new caste society between those with “normal life” and those with “extended life”.

            The proper way to frame the moral imperative to retard human aging is to ask the right question.  And that question is:  “Should we aspire to reduce the risks of morbidity, frailty and disability in late life?”  The answer to that question is “Yes, of course we should!” 

            To make vivid the different moral stakes at interest between the aspiration to “life extension” and increasing the human “healthspan”, compare the contrasting moral sensibilities the following two aging scenarios invoke.  The first scenario (Scenario 1) describes what many would take to be a dystopic life extension future, and the second scenario (Scenario 2) is a more utopian one.  It is the latter that an applied gerontological intervention could help us realize, but the “aging status quo” is taking us in the direction of (a less extreme version of) Scenario 1.

Scenario 1:  Extended Life = Extended Survival (accompanied by extended and more severe frailty, disease and disability)

Over the next half a century population A increases its life expectancy at birth by 40 years, from age 80 to age 120.  This increase in life expectancy is primarily achieved by simply forestalling death in late life.  The procurement of additional decades of life in late life is achieved not by altering aging, but from advances in improving survival to the upper limits of maximal longevity.  Through a combination of novel and expensive drug development, coupled with extensive public health expenditures in long-term care facilities and palliative care, patients can now survive for decades on chemotherapy and radiation, reliant upon ventilators, etc. enduring dementia and other severe diseases, frailty and disability for decades.  The majority of the people surviving past age 110 have little psychological continuity to their former selves, as new diseases of the brain emerge with the extreme longevity achieved (but with minimal improvements in treating these cognitive disorders). 

The only real achievement for population A in this scenario, from a population health perspective, is increased survival and a prolongation of the period of disease, frailty and disability in late life.  The “longevity dividend” (Olshansky et al 2007) achieved in society A is very costly, with ever increasing healthcare expenditures being invested in preventing death in late life with little to no regard for the “quality of life” of people in late life.  Family members learn to normalize the practice of spending many decades visiting family members in long-term care facilities, and those family members over age 100 typically can not live independently and many are no longer capable of actively participating in family life. 

Consider now a contrasting future of life extension: 

Scenario 2:  Extended Life = Extended Healthspan (increasing health and decreasing frailty, disease and disability).

Over the next half a century population B increases its life expectancy at birth by 40 years, from age 80 to age 120.  This increase in life expectancy is primarily achieved by extending the human healthspan, which means a substantive delay and compression of disease, frailty and disability in late life.  The procurement of additional decades of life is achieved by a relatively inexpensive drug that re-programmes the human metabolism to mimic the longevity effects of caloric restriction (without people having to endure the deprivation of actually consuming less calories than that required for a normal diet).  With this public health advancement it takes the average person 120 years to biologically age what use to be achieved in 80 years.  Furthermore, at the end of life there is a compression of morbidity, meaning the period of time people suffer age-related health maladies (e.g. disease, frailty and disability) is shorter than the period they experienced before the aging intervention.  Thanks to this aging drug, most people will be capable of working well past age 100, though many decide to spend the additional years of healthy life volunteering in their communities, helping out with childcare duties for their grand and even great grandchildren, etc. 

People in this second scenario enjoy more health in late life, and thus the “longevity dividend” in population B also brings significant economic benefits.  By expanding the opportunity for people remaining productive in late life, and reducing the public expenditures typically spent helping persons manage the co-morbidities of late life, population B reaps significant economic, as well as health, benefits.   

The two contrasting scenarios of populations A and B are deliberately exaggerated in terms of stark negative and positive health and economic outcomes, to reveal how such details activate different moral sensibilities in terms of our considering the desirability of “life extension”, for both individual lives and populations.  Population A realizes perhaps the worst outcome most people could envision for aging populations- prolonging the suffering, disease and frailty of diminishing health in late life at an exorbitant social cost.  Such a society fanatically values “quantity” of years survived over the “quality” of the life lived, something most people would disagree with.  Surviving many additional decades of life with progressive and severe infirmities and minimal psychological wellbeing is not something most people would see as a desirable outcome.

The “longevity dividend” realized in scenario A is one that prioritizes “adding years to life”  instead of “adding life to years”.  Scenario A is not a cost-effective, nor morally laudable, aspiration.  The quality of life secured by the 40 year increase in longevity is very relevant to our assessment of the value of such an increase in the lifespan.  And with the details provided in Scenario A, many people might (reasonably) take the view that the society would have been better off not aspiring to increase life expectancy further than the original age of 80 years.

In scenario B the “longevity dividend” is the opposite of that in A.  Population B realized the goal of “healthy aging” vs simply delaying death.  The health benefits secured in B are meaningful and substantive because people enjoy more health, and thus life extension is simply a by-product of increasing the healthspan vs the intended goal.    The reason I believe geroscience is the most significant area of scientific research, and an applied gerontological intervention the most important public health intervention of the 21^st century, is that such an intervention could make a future like Scenario B a reality.  No cure for any specific disease of aging would come even close to making this a reality.  In fact a cure for just one disease of aging is compatible with the realization of the dystopic future described in Scenario 1.  But an intervention that simultaneously delays and compresses the diseases, frailty and disabilities of late life will could a significant health impact on the 2 billion people who will be over age 60 by the middle of this century.                                                                                                 

Cheers,

Colin