The Possible End to Increasing Life Expectancy

One of the more controversial papers ever to be published in the prestigious New England Journal of Medicine projected that “the steady rise in life expectancy which had occurred over the past 2 centuries may soon come to an end.”  They ended the conclusion commenting that the youth of today may live less healthy and shorter lives than their parents.   As would be expected this paper sparked a large volume of letters to the editor criticizing this projection.  

While the authors based their projection on some very sound data, the real validation could only come with time.  As my favorite philosopher, Yogi Berra once said when asked to predict on Thursday who would win a golf tournament which ended Sunday, “ask me Sunday night.  I am a lot better at predicting the past than I am the future.”

While “Sunday night” is not here on this striking prediction about our children’s longevity, the preliminary data appears to be supporting this grim projection.  The primary basis of this projection was the ever growing rate of obesity and its relationship to increased rates of the chronic diseases such as diabetes, heart disease, cancer and many others.

As projected, overweight and obesity trends have continued upward across all population groups.  Currently about 9% of children 5 years of age and under are obese, and this rises to 20.5% between 12 and 19 years.  The increasing trend continues throughout adulthood.  Currently 38% of U.S. adults are obese and 74% are overweight.

Diabetes is perhaps the best leading edge indicator of the disease trends that may accompany the overweight and obesity change.  It is now projected that the 14.3% of the U.S. population have diabetes an increase of approximately 300% since 1990.  The real emphasis comes from the fact that fully 38%, or about 1 of every 3 persons in the U.S., is pre-diabetic with a high percentage expected to convert to full diabetes over time.

Pre-diabetes is a misleading term in some ways. Normal fasting blood glucose is 70-99 mg/dL.  Diabetes is a fasting glucose of 140 or greater.  Pre-diabetes is that zone of abnormal glucose from 100-139.  My take on pre-diabetes is that just as the first trimester of pregnancy is not “pre-pregnant” but is early pregnancy, the better term is early diabetes.

These trends are fueled by the general belief by most that no matter what they do to themselves, some medical innovation will bail them out.  At least some knowledgeable healthcare scientists seem to accept that the rate at which we can become diseased is beginning to outpace the ability to maintain chronic disease.  One trend that supports this concept is another important statistic, healthy longevity.  It is defined as age of onset of the first chronic disease.

Even as longevity has increased over the past 60 years, healthy longevity has decreased more dramatically.  This is what the authors of the NEJM paper referred to as “our children living less healthy lives than their parents”. Many treatments for chronic disease do not completely prevent the complications that often shorten life but rather they delay them.  The diabetic today has their disease longer than previous generations.

The average onset of type II diabetes was 52 years of age 40 years ago.  It is now 41 years of age.  While improvements in diabetes treatment have delayed the onset of complications, the earlier ages of onset may begin to override treatment based complication delays. 

One of the most striking papers I have read was a commentary by an endocrinologist at the University of Texas.  He had been in practice 30 years and commented that in his early years they would see perhaps only a couple of new onset cases of type II diabetes in adolescents each year.  Now they see several new cases every week.  This phenomenon was why the terminology when I was in graduate school, adult onset diabetes, was changed to type II diabetes.

This paper making these projections that received so much criticism in 2005 is being looked at as evolving reality in 2017.  Sad but true.

There is little disagreement that the primary driver of the chronic disease epidemic is diet based.  Likewise, the most effective solution will also be diet based.  Perhaps one of the best health investments we can make is to get some help from a nutritional health professional in understanding and optimizing our diet as well as that of our families.

Olshansky et al.  A Potential Decline in Life Expectancy in the United States in the 21st Century.  New England Journal of Medicine, 2005:352;11.