Skip to main content icon/video/no-internet
icon backReturn to Entries

Longevity

Longevity has frequently been used as a synonym for life expectancy in research on aging populations. However, longevity can also refer to one’s being a long-lived individual or the condition of living to an advanced age. During the past century, life expectancy increased markedly in all countries worldwide. This entry traces the history and future of longevity and the factors that are likely to influence life expectancy as well as those that affect individual longevity.

Historical Perspective

In the United States, life expectancy at birth went from 47.3 to 78.7 over the 110 years from 1900 to 2010. The country with the longest average life expectancy is currently Japan, followed by Italy, Switzerland, Singapore, and Iceland. Increasing longevity has been accompanied by an increasing number and proportion of people living to older ages. Data from the United Nations suggest that the number of persons aged 80 or above is projected to more than triple by 2050 and to increase more than 7-fold by 2100.

In the past, the risk of death was much higher at young ages, resulting in a smaller proportion of the people born in any cohort living to adulthood. However, in modern societies, most people reach old age. Improvements in longevity have resulted from the combination of advances in sanitation, public health, nutrition, medicine, and standards of living. At first, the increasing length of life resulted from declines in infectious disease and declines in deaths concentrated among the young. After most deaths from infectious conditions were eliminated, cardiovascular conditions and cancer dominated the causes of death; thus, both deaths and increases in life expectancy are now concentrated at older ages. Reductions in exposure to infections and reduction of chronic disease mortality in old age are thought to be related. The cohort morbidity hypothesis is that reduction in exposure to lifelong inflammation, early organ damage, and the need to use resources for repair rather than for growth and development has resulted in stronger bodies and longer lives among the older population.

Projections of Future Longevity

According to the United Nations, world life expectancy at birth rose by 3 years between 2000–2005 and 2010–2015, from 67 to 70 years, with the greatest increases in Africa. Some scientists are optimistic about continued increase in human longevity similar to what has occurred in the past. Other scientists feel, however, that the increase in life expectancy is likely to proceed at a more modest pace in the future. This is because the increases observed to date resulted from substantial gains in life expectancy at ages before old age, whereas increases in life expectancy at older ages have been relatively modest. For instance, life expectancy at age 90 in the United States has only increased about 1 year in the last 110 years. It is unlikely that life expectancy at birth will reach levels above 95 unless there is a fundamental change in our ability to affect the aging process. Although more people will live to very old ages, very few people will live beyond 100 years because mortality rates are extremely high at very old ages due to the exponential increase in mortality with age through the oldest years.

...

  • Loading...
locked icon

Sign in to access this content

Get a 30 day FREE TRIAL

  • Watch videos from a variety of sources bringing classroom topics to life
  • Read modern, diverse business cases
  • Explore hundreds of books and reference titles

Read next

More like this

Sage Recommends

We found other relevant content for you on other Sage platforms.

close

Have you created a personal profile? Login or create a profile so that you can save clips, playlists and searches

close
close
close Signed In to profile You are signed in as:
close
Logged in Institution Institution