At a New Year's Eve party, I asked our guests to name the major development of the 20th century. They had several excellent candidates, including the rise and fall of communism, the growth of democracy, and the advent of computers. But I believe none benefited the ordinary person more than the extending of life expectancy.
The gains in health care between 1900 and the present have been spectacular. Life expectancy at birth in the Western world grew from a mere 45 years at the beginning of the 20th century to over 75 years at the dawn of the 21st century. More than 100 infants, and about an equal number of mothers, died for every 1,000 live births in 1900. Both the infant mortality rate and deaths of women during childbirth have become rather negligible. The incidence of contagious and other diseases also drastically declined, especially during the second half of the century. Death rates in the U.S. from heart disease are less than half of what they were in 1950, and survivor rates from many forms of cancer have improved during the past two decades.
Just as impressive has been the trend toward much greater equality in terms of longevity. At the start of the past century, many people died at young ages from diphtheria, tuberculosis, influenza, and other infectious diseases, while others survived into old age. Now, almost everyone born in moderately well-off nations lives beyond the age of 60. Moreover, many deaths are no longer caused by forces beyond an individual's control, but instead are due to drunk driving, smoking, alcoholism, drug overdoses, AIDS, suicide, and other factors that can be largely eliminated by changes in behavior.
Although higher-income and better-educated whites in America still live longer than other groups, these differences are much smaller than they were a century ago. The poor and least-educated gained enormously from medical insurance, government-subsidized health care, and the discovery of cheap diagnostic tools for the early treatment of major diseases.
The one major exception is the widening gap between men and women. Women's advantage in life expectancy was negligible in 1900, but during the 20th century rose to about seven years. Women are obviously much less prone to heart attacks and strokes, two major killers of modern times, although the gender difference in death rates due to these causes has begun to narrow.
Improvements in survival to old age were not limited to richer or Western countries, and occurred on every continent and in all nations. In fact, the decline in mortality rates has been greater in poorer nations. The average person born in India will live to well over 60 years compared with under 50 years three decades ago, and only a little over 20 years at the beginning of the 20th century. The typical Mexican in 1930 died before age 40, but now mortality in Mexico is only a little behind that of rich countries.
YOUNGER OLDSTERS. Falls in the mortality figures deserve to rank among the most significant events of the past century because people highly value even modest declines in death rates. Economists have estimated what people are willing to pay for lower death rates at various ages (BW--Apr. 19, 1999). William Nordhaus of Yale University has turned these estimates of the value to people of improved mortality into units of income, adding them to national income figures of the U.S. during the past half century. He finds a huge effect: National incomes grew about 2% per year more rapidly after the adjustments for mortality declines. Moreover, since mortality fell faster in poorer countries, similar calculations for all nations would show far more narrowing of world economic inequality during the past century than is suggested by the usual comparison of national income accounts.
Some geriatric specialists expect gains in life expectancy to slow appreciably during the coming decades because deaths are now caused mainly by seemingly intractable diseases of old age. However, the mapping of gene structures that is almost completed is likely to produce vaccines and gene therapies that will combat heart disease, cancer, and stroke, the three chief killers of the elderly. This is why I believe that life expectancy, as well as the quality of life at older ages, will continue to improve rapidly during the next few decades.
The greatest declines in mortality of all time occurred during the past century. Yet this new century is likely to do still better in delaying the onset of diseases of old age. Even 75-year-olds may be "youngsters" by the year 2100, and some of you may witness these changes as members of an alert and active elderly population.