Mortality Rate is a Lesson in Big Picture Thinking

Mortality rate is a statistic that is is used regularly to measure the success of any campaign against a particular disease.  I hear stories in the news practically every week touting the reduction in mortality rate for one disease or another due to some new treatment, enhanced screening, or better public awareness.  This has been a continuing trend for over one hundred years, with the the United States age-adjusted death rate dropping from over 2,500 per 100,000 in 1900 to around 700 per 100,000 today.  It is really a remarkable decline that is due to the huge advancements made in medical science over the last century, which included vaccines for many deadly illnesses and the invention of antibiotics.  This rapid decline is also responsible for the large increase in life expectancy over the same period, raising from less than fifty years in 1900 to almost eighty years today.  It is a side effect of modern science that has allowed for the increase in economic output and general life comforts that we take for granted.

Death rates have declined rapidly over the past century, while life expectancy has increased
at a similar rate.  This is a good lesson in showing causation rather than just correlation.

Mortality Rate is a Small Slice of a Large Pie

One has to be careful whenever they hear about a study purporting a decrease in mortality rate, however.  Many studies purport a decrease in mortality rate, but it is almost always in regards to the mortality rate of that specific disease.  A report suggesting a decrease in the mortality rate from one particular disease does not necessarily mean it will cause the same decrease in overall mortality rate. Life expectancy may increase, or the mortality rate for another disease may increase due to this change. It is not immediately apparent to some, but this is due to one, very unfortunate fact: everyone dies eventually.

A drop in the mortality rate for any disease is good news, especially when that disease is a large killer like cancer or heart disease.  If, for example, ten out of every ten thousand people die per year due to heart disease, and some new treatment comes along that drops it to five in ten thousand, everyone would celebrate the achievements of modern medicine.  At the end of the day, however, those five people out of ten thousand (or 150,000 per 300 million)  that would have died from heart disease and are now alive will eventually die of something else.  They are not given a pass to live on forever.  One day down the road, something else, be it a car accident, cancer, or just old age, will end up taking their lives.  This will mean that overall life expectancy will go up due to those people living longer, but the mortality rate of some other diseases will increase due to the increase in people available to get that disease.

This a good lesson in looking at the big picture, because as Newton's third law of motion so famously puts it, "For every action, there is an equal and opposite reaction."  The effects of decreasing the death rate of one particular disease do not end at that disease.  All causes of death are affected, and many for the worse.  In 1900, the leading cause of death was influenza and pneumonia, but by 1960 heart disease topped the chart, largely due to people surviving bouts of flu and other infectious diseases thanks to antibiotics and immunizations.  Life expectancy increased, but those people eventually succumbed to other diseases, in this case heart disease.  We are destined to continue this slow march of progress, continually increasing the life expectancy while shifting leading causes of death, unless science provides people with the ability to live forever, which is really impossible since the world works on probabilities, not absolutes.

Cancer will be the Leading Cause of Death in the Near Future

Just based on statistics, cancer as a whole will be the leading cause of death in the very near future.  We are all ageing and being bombarded with ionizing radiation from the sun, and if you live long enough, no matter how good your genes are, you will get cancer.  It is just a fact of probabilities that no matter how unlikely it is that you will get cancer in any particular year, that probability will never reach zero, and the longer you live, the more likely it is that you will develop some sort of cancer.  Science has made many strides in treatments for cancer, and maybe one day the mortality rate from cancer will be almost zero, but at least for the foreseeable future, people will be developing cancer at greater rates as deaths from other diseases decreases.  I am very optimistic that we will develop cures for most types of cancers within the next twenty to thirty years, however, which should mean that mortality rates for all causes of death will decrease, but it doesn't.  There is still one remaining cause of death that we will never be able to completely eliminate, and will become the leading cause of death in the further future.  Accidents.

Accidents are the Final Leading Cause of Death for Humans

I am confident that science will continue to chip away at the diseases and other sources that contribute to the overall mortality rate, but no matter how effective modern medicine becomes, accidents will never be completely eliminated.  We can add safety features out the wazoo, but the probability of dying from some freak accident will never reach zero.  Even if all diseases are cured and no one dies of cancer, heart disease, or other natural causes, you will not live forever.  Statistics will eventually rear its ugly head and get you involved in some sort of fatal accident.  It is inevitable, as long as mankind continues to build and travel and just live.  What life expectancy would be in the Utopian scenario is really anyone's guess, but it could potentially be in the thousands of years.

The lesson here is to take a step back, and make sure you are seeing the entire picture.  The world runs on cause and effect, and if you do not look at everything, you can miss a large portion of what is happening.  Do not just assume that what you are looking at is all there is.  Your actions can have wide-ranging effects on your surroundings, and many of those effects can be completely unexpected.  The world is a very complex organism, and focusing too narrowly on one particular aspect of it can cause you to miss what is really happening.  Always be sure to sure to stand far enough back to take in the whole picture, or else you may miss the forest for the trees.