S. Jay Olshansy, Chief Scientific Officer, Lapetus Solutions
Aubrey de Grey, Co-Founder & Chief Scientific Officer, SENS Research Foundation
Stuart McDonald, Head of Demographic Assumptions and Methodology, Scottish Widows
Moderator: Paul Kitson, Partner & Pension & Savings Disruption Lead, PwC
PAUL: To start us off, give us a brief overview of your thoughts on human life expectancy and in particular, what’s likely to change?
AUBREY: My personal view is that both in the U.K. and in the wider developed world we are likely to continue to see an increasing levelling off of life expectancy in the short term. We may even see a slight decline in life expectancy by the traditional measure and early period life expectancy in some countries. The USA leading the charge in that race to the bottom.
But in ten to twenty years-time things may be beginning to look very different. We may be starting to see the signs of the next revolution in medicine, a revolution that will see a change in the trajectory of life expectancy. It could be even more dramatic than what we saw one hundred and fifty years ago, when the ability to contain and avoid early death from infections became increasingly widespread.
This will occur as a result of what I call rejuvenation medicine. In other words, medicine that actually turns back biological age rather than just slowing down biological age advancement. Of course, we don’t know for sure that this technology will come along twenty years from now. But the present challenge is worth waiting for.
JAY: As we all know, life expectancy rose by about fifty years in the last century or so. It’s decelerated in recent years in spite of people claiming that it will continue to increase as it has in the past. This recent deceleration in the rise in life expectancy and even decline should not be news to most people. It’s been predicted by many for almost thirty years now.
Exactly why it’s happening also should not be a surprise. That, too, has been discussed extensively in the scientific literature. The logic behind these life expectancy models is based on the use of blinders, looking only to the past and extrapolating into the future. This is a really bad idea as we know that the future cannot be like the past, and we can no longer achieve the gains in life expectancy that were associated with reductions in infant child and maternal mortality. Ageing is what gets in the way, and we can’t modify ageing - yet.
I agree with Aubrey that we don’t know when it’s going to be, but I’m very optimistic that we are going to find a way to break through this longevity ceiling.
Now, whether or not we can achieve gains in life expectancy in the future that are on par with what we saw in the past, unlike Aubrey, I’m sceptical that that is going to happen. Keep in mind that you when you save children from dying, you add seven, eight, nine decades of life. The increases in life expectancy are dramatic. You would have to add the same seven, eight, nine decades of life to a 70-, 80- or 90-year-old today to achieve the same result. I haven’t seen any evidence presented to suggest that that is even remotely possible.
I believe that as long as we live now is about as long as we’re going to live, based on current technology, on what we’re capable of doing today. I’ve referred to this as peak longevity. That shouldn’t be interpreted to mean that there is a biological limit specifically for the purpose of keeping us from living longer. It’s a limit imposed by body design.
STUART: I agree with much of what Aubrey and Jay have said, and sit between their two viewpoints on where life expectancy is headed over the next couple of decades. Despite the deceleration in life expectancy gains that’s been called out, life expectancy in the U.K. today is the highest it’s ever been. It’s rising and has been for more than a century.
I think comments so far have focused on total life expectancy from birth. I’m an actuary looking at insurance and pensions risks. That means I’m most interested in life expectancy for members of pension schemes. I need to make allowance for expected changes to death rates during the remaining lifetime of those pensioners.
Life expectancy for a 65-year-old retiree today is about twenty-two years for males and about twenty-four years for females. That’s higher than many people realise – it’s a real concern that people systemically underestimate how long they are likely to live when making financial plans.
I’m expecting life expectancy to change relatively slowly over the next five to ten years, but then potentially more rapidly after that. I’d anticipate about a one-year increase in the life expectancy of retirees over the next decade and then maybe another one to two years increase on top of that in the 2030s. Personally, I’m much more confident in the first prediction than the second one. The level of uncertainty increases pretty rapidly as we look further ahead.
PAUL: Aubrey, could you explain some of the big developments, or perhaps barriers that need to be overcome, in order to unlock the potential of transformative regenerative medicine?
AUBREY: Rejuvenation is damage repair. It is restoration of the molecular and cellular structure and composition of our tissues and organs to something like how they were at an earlier age in early adulthood. It’s a divide and conquer approach.
Some stem cell therapies are going really well right now. There are clinical trials in indications like Parkinson’s disease attempting to demonstrate repair of damage from ageing. There are also clinical trials in removal of senescent cells, or zombie cells that are hanging out, not necessarily dividing, but not dying when they should and creating difficulties for their environment.
The most difficult areas are mitochondrial mutation accumulation and also the loss of elasticity of various tissues, especially the artery walls. I’m delighted to say that in the past couple of years we have had enormous breakthroughs in these areas. At this point, we can be a lot more optimistic about how soon we may actually reach a decisive level of comprehensiveness in our ability to repair damage and thereby cause people to remain youthful. Of course, that will have a consequence on mortality rates, irrespective of how long ago they were born.
PAUL: Jay, the question I want to put to you is around life expectancy metrics. How we use them and what should our focus be, or not be?
JAY: First of all, the metric of life expectancy itself is not a good one, it’s an insensitive one. The higher it gets, the more difficult it becomes to move it further. I’m not a big fan of using life expectancy for just about anything, truth be told, and certainly not forecasting. It’s just not going to move that fast.
Really, our focus should not be trying to make us live longer. We should be focused on extending the period of healthy life. A longer life extension without health extension could very well be harmful. Now, chances are we’re going to live longer as a result of ageing science’s impact on health span. How much? I don’t know, but I don’t actually care all that much about how much longer we might live. I’m far more interested in how much more we can extend the period of healthy life and compress the period of frailty and disability at the end of life.
I agree with Aubrey that there are really exciting lines of research now going on in the study of senescent “zombie” cells as well as the clinical trials on metformin that are beginning.
But it’s not going to be easy to determine the effect on lifespan, because it takes too long to study. Anybody claiming that these interventions will make people live ten, twenty, fifty years longer is making it up out of thin air. There’s no way to possibly know what the effect will be on a population. The point I’m making is that you have to be careful about the absence of legitimate scientific methods for assessing longevity, and the effects of any intervention that we’re looking at.
By contrast, healthspan can be measured quickly and easily. Scientific tools allow us to understand the effects of interventions on healthspan far more efficiently and more effectively, and within a short time period. So that’s the reason why I’m suggesting that we focus on healthspan rather than lifespan.
AUBREY: Let me just add to this. I am characterized often in the media as taking a view that rather strongly departs from what Jay just said. People call me the Prophet of Immortality and so on. This is very frustrating. Pretty much all of what Jay says is absolutely identical to my own view. I’ve been getting more and more aggressive over the years onstage and on camera making this point: lifespan is a side effect of health.
With regard to testing, though, I think we can do better than what Jay had just said. We have seen in model organisms that some interventions don’t just reduce mortality rates in the near term, but also throughout the remaining lifespan. Then it’s a reasonably justified extrapolation to determine what this probably means for lifespan extension even from a short-term study.
Some of the interventions we’re talking about may or may not be as effective in extreme old age as they might be if they begin earlier in life. But I think this just points to the difficulty in generating research designed to test a hypothesis within ageing. It’s not untestable, it’s just the difficult one to do.
PAUL: Stuart, you’re the actuary who thinks about life expectancy risk in the context of pensions. This discussion really demonstrates the sort of challenges an actuary might have in managing risk. What are your thoughts on this debate?
STUART: I take some comfort from the fact that I am not having to forecast for younger people. As you can tell, there are a wide range of views even among well-informed experts. There is a significantly narrower range of possible futures when considering only older lives. Actuaries shouldn’t get too much confidence from their ability to forecast life expectancy for retirees and extend that down to younger age groups without allowing for the additional uncertainty.
The first thing that actuaries need to do is to get their starting point right. We’ve talked a lot about how things will change in the future. Actually, the difference between the life expectancy of richer and poorer groups today is bigger than the uncertainty around how the population death rates will change in the next couple of decades. It’s really crucial to allow for these socioeconomic differences, both in assessing current mortality rates and also the rate of future change. We’ve seen a slowdown in the pace of mortality improvements over the past decade within the general population, but it didn’t affect everybody equally. So, we need to allow for the possibility that more affluent groups may well continue to outperform the average level of mortality improvement.
Actuaries increasingly need to cast a very wide net when forming their views on life expectancy. Relevant developments are coming from many different fields, including some of those discussed already today. We need to rely on the expertise of others, but also appreciate the limits of those expert opinions. For example, a cardiovascular expert asked thirty years ago about improvements in preventing and treating heart attacks and strokes might have missed the impact that technology like mobile phones would have, through reducing response times.
Finally, we need to be realistic about our ability to make these forecasts. We need to ensure that the institutions we are advising will be solvent in cases where life expectancy increases more rapidly or indeed more slowly than our best estimate view. A key part of our role is communicating uncertainty rather than producing a single deterministic projection.
PAUL: The question of inequality is one that is paramount in longevity. Do you have a view on the potential for the benefits of this research; will it become the preserve of the rich and affluent? Will it be available for everyone or will it exacerbate the socio-economic divide?
AUBREY: The question of whether and when this medicine comes along is, of course, a very open question. It’s pioneering research. However, the question of what happens when it comes along is not an open question at all. It’s completely clear to me. These therapies will reach everyone and anyone who is old enough – irrespective of ability to pay.
This is because it would be economically suicidal for governments not to make sure that they frontload the investment that’s required to build the infrastructure and train the medical personnel and so on. The overwhelming majority of medical expenditure across the entire industrialized world is directed at the health problems of later life. Governments and society stand to gain an insane amount of money by a focus on prevention and preventative healthcare. Jay was a prominent participant in an important initiative more than a decade ago called the Longevity Dividend Initiative, in which this was pointed out. Things haven’t changed since then.
JAY: That said, there isn’t anything of value in the world of medicine and public health that is equitably distributed. Nothing. Clean water. Fresh food. Access to health care, income, education. All of these factors influence longevity. The forces that they exert on survival prospects are dramatic. They are not small. They are not equitably distributed.
Let me first emphasize something I consider of great importance. This is the next big breakthrough in public health, on par with what we saw in the middle of the 20th century with the introduction of antibiotics, the advent of vaccines and the emergence of basic public health services. We are talking about a huge sea change. I share Aubrey’s optimism that this is going to happen. Not only is it going to happen, we need to be aggressively pursuing it for all of the obvious reasons.
However, I don’t anticipate it will make its way equitably to the population to begin with. Some of these compounds or potential genetic interventions are likely to be costly and anything that is costly is not going to be equitably distributed. Now something like metformin, for example, could be different. It is an inexpensive drug that could make its way to the population very much like aspirin.
PAUL: Stuart, what is your sense of longevity and the gaps between different socio-economic groups? Will we see the them converge? Do you have any view on what’s caused the difference over the last few years?
STUART: Whether the life expectancy of different groups will continue to diverge, or will converge probably depends on the timeframe you measure. I do expect some further divergence in the near term, with perhaps some convergence to follow thereafter. As a rule of thumb, when life expectancy is increasing slowly as it has in recent years, it tends to mean that the gap between rich and poor is getting larger. That’s a simple function of the fact that you get the most “bang for your buck” in increasing life expectancy when you focus on those at the more deprived end of the spectrum. It’s mathematically similar to Jay’s earlier point that you increase average life expectancy much more when you save a child than an older person.
A few things that I think could make a real difference in years ahead, and which could have a different impact on different socio-economic groups, would be public education, particularly around things like diet and exercise; nudges, like the recent sugar tax; moving towards a total smoking ban; and any changes to access to medical and social care. These are absolutely crucial to life expectancy.
There’s a big dependency on the extent to which governments are prepared to direct increased funding towards those areas to meet the demands of an ageing and growing population. How governments invest in these public health issues will be very relevant to the level of life expectancy increase that we see, and how equitably that’s shared across the population. If you could bring everybody up to the level of the least deprived ten percent that would make a much larger difference over the next twenty years than any of the sexy new science.
JAY: My colleagues and I published an article several years ago entitled Two Americas at the Dawn of the 21st Century, where we were arguing the same thing – that there is a vast difference among population subgroups and it’s going to grow larger. There was also a paper that came out in the Journal of the American Medical Association that documented in great detail the disparities that exist in life expectancy in the United States and the cause of the decline that’s actually been occurring since about 2010. Part of the takeaway message from this latest research is that the issue, at least in the United States, is a systemic problem of disparities. It’s not one that is getting better, but one that is getting worse. As a systemic issue, it means that the problem is going to echo across future generations.
AUBREY: Let me clarify my position on this particular point of inequality, as I fear I may have given the wrong impression. It is not that I think that there’s going to be absolute egalitarian access to this. Of course, there is a great deal of disparity in terms of access and ability to pay to some public goods, like education, for example. But if we look at basic education for young kids it is actually pretty much free at the point of delivery, irrespective of ability to pay, even in the USA. I think that we will see universal access to the basics and that that will have a pretty rapid impact on life expectancy, whether period life expectancy or anything else.
PAUL: Let’s change tack a bit. One of the things I’ve seen commentators talk about in the field is the ability for one to find out one’s biological age. We’ve already seen one case in Germany where a man went to court to be recognised by biological age rather than chronological age. What are your views on the science of biological age, or the role that biological age may play in helping people understand ageing?
AUBREY: It’s an extremely big area right now, and it’s big scientifically, medically and socially. Scientifically, measuring biological age is getting better.
However, on the medical side, we are still a long way away because we need to identify a measure of biological age which not only predicts the onset of a disease, but also correlates when you introduce a new intervention. That, of course, was not involved in the development of the biological age measure because the intervention is new. It’s going to take a long time to identify measures of biological age that are robustly correlated in the context of new interventions of a variety of different types.
On the sociological side, it is also really important. A lot of people just don’t want to know when they’re sick. They don’t want to know that they have a cancer diagnosis. It’s similar with biological age, when the ability to actually do anything with this newfound knowledge is very limited or is perceived to be very limited. A lot of people just don’t want to know. I think a huge amount of public education is needed to encourage people to understand their biological age. It’s becoming something that people can actually act on.
JAY: I would disagree. Let me address the claims that we can actually measure somebody’s biological age. It’s not currently possible to measure anyone’s biological age, period. We can’t say you’re chronologically 60 and biologically 55 with any degree of confidence. Let me be clear about that.
Now, that doesn’t mean that there aren’t tests being developed to give us clues about the rate of biological ageing. Or that we may not necessarily be able to place you quantitatively into a given score or age. We may be able to say that somebody is ageing more rapidly or more slowly than the average person in the population. There’s a lot of information that can be used by, for example, the life insurance or health insurance industries that can place people more reliably in certain risk pools.
Methylation age is one of the metrics developed relatively recently that has a lot of promise. My colleagues and I have developed a metric based on face age, which illustrates the documented relationship between how young or old you look relative to your chronological age. It’s not a statement that you’re this many years younger or older, but it seems to be a reasonable biomarker giving you a clue that you might be ageing more slowly or more rapidly.
There is a whole suite of metrics being developed to get us towards a biological age metric of some kind. I think it’s just being sold to the public too soon. What’s out there today is more gamesmanship than anything. You cannot calculate anybody’s biological age based on anything that we can do today. However, there are tools that we can use to place people more reliably in particular risk pools.
STUART: I find the concept of biological age fascinating. Physicians can make a relatively accurate estimation of frailty and potentially life years remaining from visual assessments. It’s really compelling to think about when those assessments are more technology enabled and where that might take us.
Looking at life years remaining might be a way of helping people, particularly when they’re thinking about retirement planning and their financial futures. Talking about life years remaining is perhaps more meaningful to people than the concept of chronological age. People intuitively and quite wrongly compare their own chronological age with the chronological age of previous generations. It would be very cool if people looked at their biological age rather than chronological age and could in theory then come up with a highly personalized life expectancy forecast.
Of course, even a personalized life expectancy forecast doesn’t help much with predicting our individual lifespans. There’s a lot of natural variation in lifespan, and more than half of us will exceed our life expectancy, often by several years.
PAUL: Thank you all, gentlemen, for your contribution. I think this discussion goes to show that this is going to continue to be a very lively area over the coming years.
This article is an extract from the Longevity Trends 2020 report.
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