Tuesday, June 02, 2009

Idealism Meets Realism: Tackling Chronic Disease Via Age Retardation

An idealist is one who aspires to bring about a better state-of-affairs than those realized in the status quo.

The idealist looks at the world around them and says: "Things could be better, things should be better. Let's get it done".

Most of us are idealists about some things. The world needs more idealists.

A realist is one who grounds their aspirations in an understanding of the constraints of reality.

The realist looks at the world around them and says: "While we might not always like the ways things are, we should not forget how bad things used to be and how difficult (and sometimes fleeting) positive change can be. Meaningful progress can be made, but it takes time and much more than good intentions."

Most of us are realists about some things. The world needs more realists.

When I reflect on my own beliefs and aspirations I realize how intricate and complex this balance of idealism and realism is. There are some things I am an idealist about, and some things I am a realist about.

When I hear someone championing a cause that perhaps coheres with my idealist sensibilities, but clearly violates my realist sensibilities, I usually categorize their aspirations (after a thorough re-examination of my own realist and idealist sensibilities!) in the "naive utopian" pile of ideas.

Conversely, when I hear someone making a pragmatic argument that is perhaps sympathetic to my realist sensibilities but contravenes my idealist sensibilities, I usually categorize their aspirations (after a thorough re-examination of my own realist and idealist sensibilities!) in the "too conservative and unimaginative" pile of ideas.

The tension between my idealism and my realism helps keep my goals and aspirations in check. I don't espouse ideals that I think are unrealistic (like control of the global surface temperature) nor are my ideals tempered by realist constraints that I genuinely believe are not, in the long run, insurmountable.

Between the extremes of the cockeyed idealist and the short-sighted and unimaginative realist lies the tenuous temperate of the "realistic idealist".

The idealist in me aspires for a world with less disease. Such a world would provide humans with greater opportunities to flourish: more opportunities to love, to play, to spend time with friends and family, to cultivate new interests, etc.

A world with less disease is a world with more health. Many things impede the ideal of a more healthy world- poverty, infectious diseases like HIV and malaria, inactive lifestyles, etc. And so the idealist in me recognises that many, many things must be done to make the world a more healthy world. There is no single, "silver bullet" solution to all the risks of morbidity that humans face in the world today.

The realist in me then thinks: OK, let's take this ideal a bit further by prioritizing among the various things that could be done to improve the health prospects of humanity. To do this we must ask two important questions:

(1) what causes most disease in the world today?


(2) what are the most likely, and cost-effective, interventions that would yield the most significant health dividends?

The idealist in me can't help but admit that these realist sensibilities are important considerations. So I agree to incorporate these empirical considerations into my "big picture" grasp of the challenges, and potential solutions, to the world's health problems.

So let's consider the first question: what causes most disease in the world today? Well, if we head over to the World Health Organization we realize that most disease-related deaths are caused by chronic diseases. In the year 2005, 55 million people died, and chronic diseases were responsible for 35 million of these deaths. That number is twice the number of deaths due to infectious diseases (including HIV/AIDS, tuberculosis and malaria), maternal and perinatal conditions, and nutritional deficiencies combined.

OK, so these real-world facts make it clear that, among the problems facing the health prospects of humanity, chronic disease is a BIG problem. And it is not a problem just for the richest countries (as many naive idealists assume). In fact, most deaths from chronic disease occur in more populous lower-middle income countries, like China and India. WHO estimates that between 2005 and 2015, 220 million people will die from chronic illness, and a 144 million of these deaths will be in these lower middle income countries.

These numbers are sobering. Never before in human history have so many people been ravaged by chronic diseases. And chronic diseases do not kill people quickly, they are long-lasting, leading to years of pain and suffering, disability and often financial hardship for families and rising health care costs.

When the idealist in me sees the data on chronic disease I say: "Things could be better, things should be better".

But how do we best combat chronic disease? While the idealist in me hopes we can make progress with treating chronic diseases, the real ideal would be to prevent them from developing in the first place. But unlike communicable diseases, which can be prevented by things like vaccinations, bed nets and condoms, chronic diseases are more difficult to prevent. There are things people can do, like quit smoking, eat a decent diet and exercise. But is there something else we should also consider?

Perhaps we are overlooking something? Something so obvious that it might have been easy to overlook? hmm... Let's back up and reflect on the fact that, historically, very few people developed, let alone died from, chronic disease. The tsunami of chronic disease that now exists is a novel development in human history. What really caused this tsunami? What explains why the 21st century is the century of chronic disease? Is it something that people now eat that is causing all these chronic diseases? Is it something in the lifestyles we now live? No.

There is one obvious reason why chronic diseases are the leading cause of death in the world: because people are living longer. Most chronic diseases are in fact caused by the inborn aging process. A 20 year-old smoker has less risk of developing cancer in the next 10 years than does a 80 year-old who never smoked in his life. And a 20-year old who eats a poor diet and rarely exercises has a greater chance of living another decade than does an 80 year-old who eats a good diet and exercises every day. The impact of smoking and inactivity pale in comparison to the impact a few extra decades of senescence has on a person's health prospects.

Maybe we have been looking in the wrong place in terms of identifying the leading causes of chronic disease. Perhaps, unlike communicable diseases that have proximate causes we can (now) easily identify- like the HIV virus and bacterium Vibrio cholerae- the real culprit to study and mitigate with chronic disease is the ultimate (rather than proximate) cause.

The vast majority of people who die from chronic disease are over the age of 60. Why does the number of years you have lived have such a strong bearing on your risk of chronic disease? The answer to this question requires us to go beyond the findings of epidemiology and the fixation on proximate causes. We need to invoke the findings of biodemography. Biodemography is the scientific study of common age patterns and causes of death observed among humans and other sexually reproducing species and the biological forces that contribute to them (source).

You might wonder why you haven't heard about biodemography before. Well, it's a relatively new new scientific discipline, just a few decades old. You might also wonder why the CDC or WHO don't invoke the ultimate causes of morbidity and mortality in their classifications of human deaths? That's a good (and very important) question. My guess is that it is simply a case of inertia. The conceptual tools and empirical insights that proved useful in helping us combat communicable diseases are still being applied (with some, but limited, success) to chronic diseases. In time this will, hopefully, change [this is my idealist speaking now!]. To change it doctors need to learn about evolutionary biology, we need to fight for science, .... well... I digress....

So what causes most chronic disease in the world today? The short answer is: evolutionary neglect. Reproduction was made a higher biological priority rather than indefinite maintenance. The post-reproductive period of the human lifespan, unlike the pre-reproductive and reproductive periods, is not influenced by natural selection. Hence why our hair turns gray, our skin wrinkles, our joints ache, and, eventually, we develop one or more chronic diseases and die.

Now let's turn to the realist question #2: what can be done? The idealist in me would see no point in listening to all the points listed above if there was no possible good news at the end of the day!! So, the short answer: we need to re-programme the human metabolism. But we must aspire to do more than follow the simple advice given by your doctor (e.g. eat sensibly and exercise, which of course everyone should do!). Lifestyle modifications alone will not be sufficient to make serious headway against the diseases of aging.

To achieve the latter we must develop a drug that mimics the effects of calorie restriction (CR). CR (unlike exercise alone) has been shown to extend the lifespan of a variety of organisms, including mice, by retarding aging, thus delaying and preventing the progression of the diseases that would otherwise have killed them sooner.

What would the development of such an "anti-ageing" drug mean for humans? It would mean that by taking a daily pill (call it the "vitality vitamin") one could reduce their risk of all age-related diseases and disorders. It would extend the number of years of health and vigour that people could expect to enjoy. Humans with a re-programmed metabolism might have the health and vitality of today's 50 year-olds even when they celebrate their 80th birthday! And when their health does seriously decline as they approach 110-120 years old, the period of morbidity would be compressed compared to what that period is under the current rate of aging.

Such an intervention is currently being tested in human clinical trials (see here). So the realist in me says "hey, this is not as far fetched as most people might think!). These trials will see if such an intervention is a safe and effective treatment for the diseases of aging. If it is, then the prospect of taking such a pill as a preventative measure, by retarding the rate of aging, is on the table.

Given where the science already is, with more support and a serious push perhaps today's adults could expect to add a decade of healthy life and compress morbidity at the end of life. And for the children of today, its conceivable that just over 3 decades of extra disease-free life could be enjoyed, compared to what the current rate of aging offers.

So what is a "realistic utopia" for the 21st century? In my view, it is a world where our children do not have to suffer the late-life morbidity that our parent's generation suffered. Age retardation would increase the human health span and compress morbidity at the end of life. This would constitute incredible progress towards my ideal of a world with more opportunities for health (though we would still need to tackle poverty and infectious disease). A world of humans with re-programmed metabolisms would mean a world where people can spend more time with loved ones and friends, more time learning about this fascinating world and universe, more time playing, and..... it would also create enormous economic benefits.

Few people in the world today believe that decelerating human aging is (a) possible and (b) an important priority. So the realist in me knows that it will be a difficult battle to fight for the realization of this ideal. But progress is being made towards this ideal as I write these words. Below are a few random links worth visiting to just get a brief glimpse of the fascinating research being done on aging. These kinds of research could lead to applied gerontological interventions that help treat and prevent the chronic disease of aging.

One... Two... Three... Four... Five... Six... Seven... Eight... Nine... Ten... and the list goes on.... [and I can't leave this important one off the list!]

Championing the cause of age retardation reflects my stance as a "realistic idealist". The most plausible and effective way to really tackle chronic disease is to delay their onset via retarding the rate of the inborn aging process. We can already do this for a vareity of organisms, including mammals like mice and monkeys. So let's do it for humans! Let's leave future generations something that will really improve their lives. Let's leave them a re-programmed metabolism that picks up the slack left by evolutionary neglect.