I’ve recently read several articles dealing with the aging of our population. They all said that retired people have to confront the problem of a longer life expectancy. They have to husband their resources to last longer than did previous generations You’ve probably seen similar material. Everybody believes that old people are living a lot longer than did their forebears. The problem is that it isn’t true.

In 1850 the life expectancy for a white male at birth was 38.3 years. In 2006 it was 76 years – almost 40 years more. But that doesn’t tell us the fate of old people then or now. In 1850 a 70 year old white man had a life expectancy of 10.2 years. In 2004 a 70 year white man could expect on average 13.7 more years of life. Only a three and a half year increase over more than a century and a half.

These observations have some fascinating explanations and important implications. In 1850 and well into the 20th century children died at an astounding rate. They died from an assortment of infectious diseases that are rarely seen today in the developed world. Deaths from these diseases virtually disappeared because of routine inoculations, antibiotics, and most importantly modern plumbing, sanitation, and hygiene. The plumber by separating drinking water from sewerage has saved more lives than all the physicians who have lived or ever will live. So don’t complain the next time he charges you a couple of hundred dollars for a house call. He’s saved your kids’ lives.

People who don’t die young get the chance to grow old. We have more 80 year olds mainly because we have more 40 year olds. Put another way, there are more 80 year olds not because of better geriatric care, but because of better pediatric care. In 1850 20 year olds had a longer life expectancy than did newborns emphasizing how perilous childhood was back then.

Everyone is concerned about the financial train wreck that Medicare is or soon will become. This is on top of the train wreck already here. The following question is inescapable. Is spending 10% or more of GDP to buy old people another three years of life a wise investment? The elderly undoubtedly would say yes. If you put a secret ballot on the question to their grandchildren I’m not sure what the answer would be.

Of course, the question is more complicated than the way I posed it. Medical care for the elderly does more than prolong life. Much of it improves the quality of life. Cataract surgery does not lengthen life, but it really improves the quality of that remaining. The same is true for joint replacement surgery. I’m sure you can think of many other examples.

But what does the relatively small increase in life expectancy say about modern treatment for the main causes of death, cancer, and heart disease? Cancer treatment has had almost no effect on mortality. The decrease in cancer deaths is almost entirely due to prevention, eg smoking cessation. We are regularly told that medical care needs to be refocused from treatment to prevention. The truth is we’ve already done this. Almost all preventable causes of premature death are being prevented. Children no longer die from infectious diseases. Nothing else we could conceivably do could have a fraction of the effect that this decrease in childhood mortality has had on overall human health.

Cardiovascular deaths have fallen in half over the last 35 years, yet old people don’t live that much longer. This suggests that when you are old if one thing doesn’t get you another will. There was a paper in Science around 1992 that suggested that if all deaths from cancer, heart disease, and diabetes were prevented life expectancy would only rise by about three years. A real but discouragingly small effect. The only way to dramatically increase human life span in the developed world is to arrest the aging process. Doing so would create a mammoth new set of social and political problems that you can work out yourself.

When a financial planner tries to sell you some instrument designed to cope with your longer post-retirement life span tell him to look at the life tables and come back later. If your grandfather made it to retirement age he likely lived virtually as long as you will.