1 July 1975

How Long Can People Live?

Linus Pauling

In recent press reports it is stated that the oldest person in the
Soviet Union had died at the age of 135 years. She was said to be lively and
in apparent good health until shortly before her death. A son, still living, is
said to be 91 years old.

From time to time reports are made of even greater ages, suchas
the Englishman Thomas Carr, said to have died at age 152. It seems likely
that some of these ages have been exaggerated. No age at death greater than
120 (?) has been substantiated by reliable birth records or other documents.

A tendency to exaggerate their age by old people was indicated by the census
of 1911, which showed a deficiency in people who gave their ages 85 to 90 and
an excess in those 91 and over.

It is possible to make a moderately reliable prediction of the number
of people who will live to be more than 100 years old, by use of the population
figures and death rates collected by the United States government. Tables giving
the number of people surviving to specified ages and the probability of death at
each age, from government sources, have been given in the Statistical Bulletin,
published by Metropolitan Life Insurance Company. According to these tables,

of 100,000 people born alive, 20,908 have survived to age 85 in the United States.
(How Long Can People Live) ~2-

The chance of surviving to age 85 is considerably larger for women than for
men: Of 100,000, 29,538 have survived to age 85, and of 100,000 men,
13,168, less than one-half as many. The explanation of greater survival

for women than for men is that the chance of dying during the year is greater
for men than for women at every age. At age 85 the chance is 12.6% for men
and 11.3% for women.

At earlier ages the discrepancy is still greater; at age 20, the death
rate for men is three times that for women; at 29 it is twice, and continues to
be twice as great to about age 70, after which the two death rates begin to
approach one another,

For both men and women the chance of dying during a given year
increases with increasing age. Between ages 75 and 85 the increase is by
7.3% each year for men and 10% each year for women.

If we ask how many men may expect to live to be over 100 years old
in the United States, and how many women, we may use the continually-increasing
death rates, year by year, to calculate the number of survivors in a population
originally of 100 million men and 100 million women. This calculation gives the
result that about 150,000 men and 430,000 women can expect to live to be 100
years old, About 5,000 men and 5,000 women can expect to live to be 105
years old, and a few, perhaps 10, might live to be 110 years old.

There is some indication, however, that very old people do not

continue to age so rapidly as younger ones. There is some evidence that the
(How Long Can People Live?) -3-

death rate does not continue to increase by 7 to 10 percent each year, after
age 100, but becomes constant, with value about 0.5 per year. Thatis,a
person who reaches the age 100 may have a chance of one-half of surviving
each succeeding year in his life. If we calculate the number of survivors of
100 million men and 100 million women on this basis, we find that 150 men
and 400 women would be expected to live to be 110 years old, 5 men and 13
women to be 115 years old, and one woman would live to be 119 years old.

No one knows how reliable calculations of this sort are. There is
the possibility that a few people have such a genetic constitution that they can
achieve an unusually long live. It seems likely, however, that the claim that
the oldest person in the Soviet Union reached the age of 135 is in fact probably
unjustified.

The conclusion that people now living probably cannot achieve ages
greater than 120 years does not mean that greater ages may not be realized in
the future. The increase in death rate with increasing age is the result of
the phenomenon of aging, which is not well understood. If investigators
succeed in finding what factors are involved in aging, what factors cause the
probability of death to increase with increasing age, some significant steps
may be taken to slow down the rate of aging, and the life expectancy could be
correspondingly increased. If the death rate at each age could be cut in half,
the life expectancy would be increased by about 8 years. It is known that

cigarette smokers have a life expectancy of about 8 years less than nonsmokers.
(How Long Can People Live?) -4-

It is probable that nutritional measures can be taken that improve health
and decrease the death rate, thus increasing the life expectancy. There

is a real possibility that research on nutritional factors and other factors
that affect the health and well-being of people could increase life expectancy
by 25 years or more, for the average American, and that some increase

could be achieved also for those people who live beyond the age 100.

(Note: Check Guinness's Book of Records, 14th edition of the Encyclopedia
Britannica, and other books. )