Tuesday, October 28, 2008

Why Worry About Aging? (Part 2)

This post continues the issues addressed in this earlier post.

While we face an almost infinite array of risks to our health and survival, it is important to recognize the fact that not all risks of harm are equal.

Some risks of harm have a very low probability of being realized (like being hit by lightening, which is around 1 in 10 000 000). Other risks have a high probability (like risk of dying from cancer, which is almost 1 in 4 for males, and 1 in 5 for females, in the U.S.).

Some risks concern harms that are minor (like your washing machine breaking). Other risks concern things that are very severe (like disease and death).

As a species we have evolved ways of avoiding some risks. For example, if you inadvertently place your hand on a hot stove your body will quickly process the danger and send the message to your brain in the form of “PAIN! MOVE HAND! QUICKLY!”. And if you cut your arm a complex process of “wound healing” will be set in motion. Inflammatory leukocytes will be sent to the wound site to protect against infection, and different tissue and cell behaviors will be triggered by the genes we have inherited from living in a world prone to mammalian skin wound.

And as a society we have adopted measures (like laws) to avoid some risks. For example, in the province of Ontario wearing a seat belt is the law. It wasn’t always the law. However, empirical evidence showed that the risk of serious injury and death (like putting your head through the windshield) could be reduced by wearing a seat belt. And now we all wear seat belts.

When we think about risks rationally- instead of letting our perceptions be shaped and molded by emotive responses to vivid images of particular kinds of risk- it makes best sense to focus on the most probable and severe harms. Furthermore, when thinking about possible solutions to these risks of harm we should consider the costs and likelihood that we can actually do something to mitigate these harms.

Putting all this together... the biggest mistake a society could make is to ignore the most certain and severe harms that could have been most likely mitigated for little cost.

Thus the following four issues are vital:

1. The certainty of the harm (e.g. 0.1% vs 70% chance)
2. The severity of the harm (e.g. broken leg vs death)
3. The likelihood of mitigating the harm (e.g. 0.1% vs 70%)
4. The cost of mitigating the harm ($1 billion vs $1 trillion)

To make serious headway in getting people to “worry about aging” we thus need to highlight all four of these issues.

Firstly, we know that senescence causes death and disease. The scientific consensus is in. So the risks of aging are very high (and eventually become a certainty of harm for most people on the planet).

The harms of aging are also very severe. Aging increases one’s risk of disease and death. So the empirical evidence clearly shows that aging scores very high on (1) and (2). These facts alone show that aging is a BIG problem.

How about issues (3) and (4)? People are most likely to (mistakenly) assume aging research scores low on both these fronts. That is, people are skeptical that we can actually modify the biological processes of aging. But there are countless experiments in a variety of organisms that show aging is not immutable. And so the goal of retarding human aging scores reasonably well on (3). And once you add considerations (1) and (2) into the mix, it becomes evident that the current neglect of aging research is unjustified.

People will also falsely assume that (4) will require vast amounts of money. But here one must put things in their proper context. A lot of money compared to what? What we spend on national defence? National defense spending in the U.S. has reached approximately $1,600 per capita, compared to $97 per capita for federal spending on biomedical research (source)

But then the story gets even more dire when we consider how much of the funding invested in biomedical research goes towards the science that could actually make serious headway against the diseases of aging- aging research. In the year 2006, the National Institutes of Health was funded at $28 billion and yet less than 0.1% of that funding was spent on understanding the biology of aging (source).

Should we increase that spending? Yes! By how much? Well, now that is an intelligent and important conversation for us to have. The answer depends on the findings of (1), (2) and (3). Contrary to what many people think, slowing aging might be as simple as taking a “a longevity pill” that mimics the effects of calorie restriction. Taking this daily vitamin could delay all the diseases of aging and increase the number of healthy years humans all around the globe could expect to live. In fact numerous clinical trials involving an anti-aging molecule are already taking place in humans right now! So this is the science of today, not a 100 years from now.

If a longevity pill could be developed, these benefits could be enjoyed by all future generations. Generations that would be spared from the ravages of the diseases of aging. Hence why I think we really need to “worry about aging”.