Unknown: Doctor, can you talk about the impact of regenerative medicine, and what would that have on longevity? What are we talking about in the big picture, not only on length of years, but on quality of life as well?
Doctor: We do not know at this point how long people will live when they received the therapies that we're working on at the moment that I think we have a good chance of developing within the next couple of decades.
What we do know, however, is that any longevity benefits that might accrue from these therapies will be a side effect of health. We absolutely will not be developing therapies that keep people alive for an unusually long time in a frail state of health, in a disease state of health that's like being old today is. It's only going to happen if and when we can restore people to a truly youthful state, not only how they look, but also how they feel and how they function.
That means that we absolutely do not need to consider the possibility of this being an uninteresting, ineffective concept, because people will be frail.
Unknown: Life expectancy has increased over the last 100 years by as much as 15, 20 years I suppose. How close are we to seeing a bigger jump do you think in life expectancy?
Doctor: The thing about life expectancy as we look at it historically and indeed project into the future, is we can't just look at trends simplistically. What we have to do we look at the underlying reasons why life expectancy has increased at various stages during history. And as you say, there has been absolutely, hardly any increase in average lifespan until maybe 200 years ago at which point things started to take off. And in particular, between about let's say 1850 and 1950, there was pretty much a doubling of the average time that people would be expecting to live.
That happened essentially because in the western world, we were able to bring infectious diseases under a very large degree of control and thereby, to reduce the number of people who would die in the first year of their life from perhaps 40 percent down to very small percentage. So of course that means that these people are going to live a lot longer, and that's going to raise the total life expectancy.
We can't do that again. It's done. Right? We can't get anymore significant increase in longevity by decreasing infant mortality or indeed mortality in childbirth. It's been done. What we can do is reduce the risk of death at ages at which people tend to die now, which of course means 60, 70, 80, 90. And that's what's been happening since 1950. The reason why longevity, life expectancy has carrying on going up is because we have had success in reducing the incidence of the life threatening diseases and disabilities of old age.
But here's the bad news. The way we've done that appears to be not really mainly through medicine. Some medical advances, especially in cardiovascular disease that have made some difference. But by and large it seems that what's happened is early life effects, what are often called cohort effects, where people are somehow biologically younger throughout their lives than they used to be. Even prenatal nutrition seems to be a really big feature in this. Of course, prenatal nutrition for people who are 70 now was a lot better than for people who were 70, 50 years ago.
So this allows people to stay healthier for longer, and therefore, as a side effect as I said, stay alive for longer. But there too, is reaching diminishing returns now. People who are 30 today, probably had pretty much the same quality of prenatal nutrition and other things as people who are 70 today. So we may be reaching the point where that is also going to, in the western world of course, is going to free its way out of the system. The rate of increasing longevity may very well level off over the next 10 or 20 years I would predict.
The question is what's going to happen after that? After that, of course, we're looking at the possibility of the therapy [inaudible 00:03:40] foundation works on, and other people, regenerative medicine for the disease and disabilities of old age. Once that gets into place, we can strongly expect to see a real takeoff. As I said, that will be a side effect of health.
UNKNOWN: You've said that you think there's a good chance there's a person alive to day that might live to be 1,000.
Doctor: I think it's possible that we could see really extraordinary life spans. We could even see people living as long as 1,000 years. Obviously, we won't see that for another 900 years. So it's really not a useful thing to be speculating about.
UNKNOWN: That's hard for people to grasp, I think, when you talk about the life expectancy now.
Doctor: It is hard for people to grasp, and that's why I say, listen, just don't be distracted by it. It is a definite distraction. What matters is staying healthy now, staying healthy in 20, or 30, or 40 years. Forget about how long you're going to live. It's not relevant.