Wednesday, February 27, 2008

More on Risks of Death and Priority Setting

Following on from my previous post... when thinking about society’s main priorities one could focus on many different facts (e.g. economic prosperity, education, disease, etc.) and moral principles (e.g. equality, liberty, etc.). And any attempt to determine what justice requires, “many-things-considered”, will involve the Herculean task of piecing the various pieces of the justice puzzle together in a way that gives due attention to the diverse, and sometimes competing, demands of justice.

One important part of the story of getting an accurate sense of the “big picture” of what justice demands is to consider what the leading causes of human death are. Though we might not want to be reminded of this fact, the reality is that human beings are intrinsically vulnerable. We can die from starvation, conflict, natural disasters, parental neglect, car accident, choking, drowning, cancer, poisoning, obesity, aging... etc. Tragically the list goes on, and on, and on….

Okay, given that risk of death is so omnipresent, then we need to think rationally about setting some priorities for mitigating, or minimizing the risks of, these various causes of death. To do this one needs a clear sense of what the most prevalent causes of death are. And the answer to this question will vary depending on where one lives (e.g. in the developed world vs the developing world). It also depends on the timeframe we invoke. If we ask what killed most people in the world in the twentieth century then we would have to acknowledge the enormous costs of war, infant mortality, infectious diseases like smallpox, poverty, etc. Some of these things will also cause many deaths in this century, and yet others most likely will not (e.g. smallpox). Just because something has, historically, been a leading cause of death does not mean it will necessarily be so in the future.

It would however be a mistake, when setting priorities, to focus merely on those things that actually have caused human deaths. There are also things that could possibly cause human deaths- such as a nuclear war, or a new infectious disease, etc. And so reasonable risk management will require us to consider the magnitude of the harms different risks pose for us, as well as the likelihood that these harms will be realized (and the likelihood that we could take steps to avoid these harms).

Unfortunately it is really difficult to get an accurate sense of what the biggest challenges facing humanity this century will be. We do not possess a crystal ball. Furthermore, our sense of reality is often influenced by sensationalist journalism, exaggerated alarmism propagated by politicians catering to the public’s fears or special interests.

Public perception of real health risks is, especially in the post 9/11 mindset, particularly troubling. How many Americans, for example, have died of terrorist attack versus obesity? Are the fears and anxieties that Americans have about the likelihood that they will be killed by terrorists proportionate to the fears and anxieties they ought to have about the quantities of food they consume, or their inactive lifestyles? How many Americans will likely die from cancer versus climate change?

And if one considers things from the global perspective, one can ask- how many will die from war, from poverty, from HIV, from climate change, from cancer, from aging?

One way to help focus our minds on the reality of the challenges facing us, without inundating us with endless statistics, is to consider the following thought experiment: think of all the people you have known who have died. The results of this exercise will vary depending on what country you live in. But for now let's assume most of my readers are in the developed world. Ask yourself what the most common cause of death has been. Perhaps you know someone who died in a car accident. Or you know someone who died of cancer. Etc.

As you try to determine what the most common cause of death has been among your friends and family, you will start to see that the majority of these people share one thing in common: they were older than you.

This is especially true for people who are not themselves that old. The older one gets the more likely it is that many of their own contemporaries have also passed away. So the diseases (cancer, diabetes, AD, etc.) and frailty of aging are the most prevalent causes of death (though it varies depending on the affluence of one's country). Aubrey De Grey puts the toll of daily global deaths caused by aging related causes at 100 000 a day. And in the industrial world, approximately 90% of all deaths are caused by ageing (De Grey, 2007: 8).

Now gathering facts about the causes of human death is a contentious business, and such facts do not completely settle all the important issues that must be addressed when setting priorities. So I am not suggesting that tackling aging ought to be our #1 priority. But appreciating the realities of what causes human death is an important step in grasping a sense of the “big picture” of things. So does an understanding of the likelihood that we can actually do something to retard human aging. Once we combine the facts concerning the magnitude of mortality and morbidity caused by our biological vulnerabilities with the amazing scientific advances that have been made in the past decade in the science of longevity, then we cannot justify the current marginalization of aging research.

If I were a betting man, I would put money on the bet that more human beings this century will suffer disease and death from DNA damage, RNA damage, oxidation, etc. than anything else. The greatest threat to our health might in fact be our own biology- the biological vulnerabilities we have inherited from our evolutionary history. If I am right, then the costs (to our health and economies) of aging must inform our decisions concerning what our main priorities ought to be. I know hearing me say this will raise a lot of questions and concerns from my readers. And I don't pretend for a moment to presume these are easy issues for us to address and discuss. But we cannot afford to ignore them.