LIFESPAN: HOW MUCH COULD WE CHANGE IT?
- 4 days ago
- 3 min read
By Morton Tavel, MD, FACP
This is an intriguing question, and while there are obviously no clear answers, it raises two important questions: 1) How long would we survive if all presently known diseases could be eradicated? 2) How far could science take us if and when we have emerged victorious over these diseases? So, let's look at each question separately.
Life Expectancy in the Absence of Disease
In 1900, average life expectancy in the USA was approximately 47 (women living about 2 years longer than men). By 1998, the average had risen to around 76 (women doing better by about 5 1/2 years. But note from the chart below (women, pink, men, black) that we made most of this progress between 1900 and around 1970. This rapid progress was primarily attributable to our victory over infectious diseases. This conclusion is highlighted by the inordinate rise in mortality in 1918 caused by the influenza epidemic (note that fall in the chart). Since 1970, the curves rose more slowly because of the more formidable gains attributable to the various non-infectious diseases. Now our biggest killers are related to cardiovascular diseases, (heart disease and strokes) caused primarily by arteriosclerosis (hardening of the arteries), and cancers of all types. Based upon the numbers below, if we could wipe out cardiovascular disease and cancer, we could allow most folks to live out a maximum number of years, based upon our current understanding of human physiology.
Causes of Death in the USA in 2010
Heart disease: 597,689
Cancer: 574,743
Chronic lower respiratory diseases: 138,080
Stroke (cerebrovascular diseases): 129,476
Accidents (unintentional injuries): 120,859
Alzheimer's disease: 83,494
Diabetes: 69,071
Kidney Diseases, nephrotic syndrome, and nephrosis: 50,476
Influenza and Pneumonia: 50,097
Intentional self-harm (suicide): 38,364
Based upon published information together with my medical knowledge, I believe that we could reach an average age of 100-110, provided at least these two major disease categories mentioned above, could be eliminated.
In the case of cardiovascular diseases, we have the answers now, provided that the various lifestyle problems and predisposing conditions could be corrected. They include improper diets, obesity, smoking, hypertension, lack of exercise, and others of lesser importance. Since prevention offers a far more effective strategy than do medications and surgical procedures to reduce mortality, meaning that treatments of all types only are of limited importance. The recently reported fall in lifespan is likely not indicative of a major trend shift, but if sustained, it would be likely due to poor lifestyle choices, especially advancing obesity.
Cancer provides a formidable challenge, possibly because it is may be multifactorial in cause and often extremely difficult to treat with our current methods. With advances in our understanding cell biology, including DNA makeup and manipulation, together with controlling immune reactions, we are likely to solve this riddle within the next few years—probably not soon enough in my judgment.
How Far Could Science Take Us Next?
The answer to this question takes us into the realm of science fiction, but for what they are worth, here are my thoughts.
Despite the great advances in such areas as organ transplantation, cell mechanics, surgical procedures, and many others, I believe that the maximum life expectancy will remain capped in the area of 110. I say this because, as noted in the chart below, we are already beginning to level off, and despite many advances in organ transplantation and other potential treatments, various targeted methods and replacements cannot support the entire body, such as muscles, bone, brain and others. Thus, the entire body continues the inexorable process of wearing out. For this reason, we are likely to be restricted by such limitations in lifespan as determined by evolution.
The assumptions stated above are merely that, but in order to advance beyond these limits we would need extreme and game-changing advances that are not possible to foresee at this time. But who knows?
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