Gompertz law

We are born as individuals and die as imitations approaching  death at an accelerating pace, so we are told. From the age of 20 years and onward mortality rate advances exponentially. Its nature was  captured by the Gompertz equation, known also as the Gompertz law  of mortality: Mortality rate = m(b) = a*Exp[b*age]. b is the mortality coefficient. When death rates are plotted on a logarithmic scale a straight line, known as Gompertz function is obtained. Log[a] +b*age.


Mortality rates for the 2002 US population. Source CDC/NCHS, National statistics system, mortality

For more than a century gerontologists and demographers claimed that this gloomy law governs our life, and  since similar equations describe the fate of machines, our organism follows the same rule. Aging is a gradual deterioration of components, and  accumulation of error. In order to  prolong the life of a machine it has to be equipped  with redundant components so that when one dies the other takes its place.  The same applies to us. Since aging is driven by an ongoing (random) deterioration  of vital genes,  in order to attain old age one ought to be equipped with redundant vital genes.

The death of Gompertz law

Then came an “unpleasant” surprise. Their models failed to account for the observed data. People lived longer and when they passed  the age of 85 years their  mortality rate started declining (!). Beyond the age of 100y  the mortality rate  approaches asymptotically a constant value. In other words, if you cross the age of 80y and you are still healthy, your chances to cross the 100y mark continually improve. Farewell to the Gompertz mortality law. The following figure depicts the yearly mortality of US females living in 1999. The source is the Human Life-Table Database  http://www.lifetable.de/

The curve looks Gompertzian and gloomy.  On a semi-logarithmic paper it traces a line, like in the above figure, whose r-square is about 0.95. However, this simple linear regressions smoothes out important detail particularly since it is logarithmic. Let's take the mortality rate acceleration MA, which  the difference between two subsequent points: MA = q[age] - q[age+1]. The next figure depicts the logarithm of the acceleration: Log[MA]. The red line is the best fit for the data between ages 30-60y  (A) extrapolated to the age of 110y.

From the age of 60y and onward more and more points deviate non randomly from the red line, which represents the Gompertz law. Obviously the Gompertz function does not account for the behavior of observed mortality. It is neither a law nor an adequate model of human mortality rate.  At the age of 75y mortality accelerates faster than predicted by the Gompertz function, and with advancing age  acceleration declines (C).

The A segment of the mortality rate accounts for a linear loss of physiological functions, due to disuse .Phase B accounts for chronic diseases, e.g. diabetes, and hypertension, which accelerate the mortality rate. Segment C was discovered only recently. It is a manifestation of  late life. Up to the age of 95y, the longer you lived the greater were your chances to die. Once reaching this advanced age, the longer you live the better your chances to reach the 100y mark.  

Aging-Yogi

What is the meaning of this plateau?  Cartesian reductionists claim that some people attain late life since they are equipped with redundant vital genes. Your chances to reach the 120y are therefore slim, since nobody has enough redundant vital genes to reach this age. However the future is bright. Evolution minded demographers hope that evolution will create a new race (Methuselahs) with ample redundant genes that will drive humanity to an ever advancing age.

Why not take destiny in our own hands and try to get older even with a small set of vital redundant genes?  Actually todays followers of Methuselah seem  to know how to reach the advanced age. Or better their Wisdom of the Body (WOB) knows how to drive them to the advanced age.  What is its secret?  Here such individuals are called Aging-Yogis.  The Yogi suffix is applied here to people with extraordinary capabilities, e.g., Cancer-Yogi   In the same way as a Hindu yogi controls his physiological functions aging-yogis slow down their aging. They carry a secret which might be applied to other people as well. This site investigates the secret of cancer-yogis.

Additional reading: How to slow down aging

Acceleration of  age specific mortality

Steven A Frank studied age specific mortality accelerations in different diseases. The following picture is part of Fig. 1 of his paper (1)

Fig. 1 Age-specific female mortality patterns. Data averaged for the years 1999 and 2000 for non-Hispanic white females in the US from statistics distributed by the National Center for Health Statistics (1) 

Initially age specific mortality acceleration rises to a peak whereupon it starts declining. Cancer mortality decelerates from the age of 50y and onward. The older the patient with cancer the better her chances. The aging organism (WOB) handles cancer better and better.  The older she gets the better her chances to become a cancer-yogi.  The same applies to heart disease. Although it starts decelerating somewhat later than cancer, the older he gets the better his chances to become a heart-disease yogi.

More in: Age adjusted cancer mortality

Aging is an ongoing process by which WOB attempts to creatively withstand external threat. What appears to us as age deterioration is a successful attempt to sustain life. The appearance of a healthy elderly is a token of his capability to  handle external threat. Contrary what the so called Gompertz law predicts  our fate lies in our hands.

References

1. Steven A Frank
A multistage theory of age-specific acceleration in human mortality ,BMC Biol. 2004; 2: 16.
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=471577

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