Life Expectancy

K.G. Manton , in Encyclopedia of Gerontology (Second Edition), 2007

Introduction

Life expectancy is the average number of years a person in a population could expect to live after age x. It is the life table parameter most commonly used to compare the survival experience of populations. The age most often selected to make comparisons is 0.0 (i.e., birth), although, for many substantive and policy analyses, other ages such as 65+ and 85+ are more relevant and may be used (e.g., for determining person-years of Medicare and Social Security benefit entitlement). To calculate life expectancy at age x (e x ), age-specific mortality and population counts are needed to determine the age-specific mortality rates (i.e., the q x ) and survival probabilities (l x ) used in life table computations. Life expectancy is determined by multiplying the sequence of the probabilities of survival at each age to determine the proportion of a population expected to survive to age x. The number of persons expected to be alive in each single year of age category after age x is summed to determine the total number of years left to be lived after the index age (L x ). The total number of person-years to be lived after age x divided by the expected number of survivors to that age yields the life expectancy at age x.

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Life Expectancy Measurements

David M.J. Naimark , in International Encyclopedia of Public Health (Second Edition), 2017

Conclusion

Life expectancy can be understood to be equal to the area under a survival curve regardless of its shape. A gain in life expectancy associated with adopting one health strategy over another (or of being in one exposure group vs another) is the area between the respective survival curves. In order to put a given gain into proper perspective, it is necessary to understand the baseline risk in the control group and the proportion of people who are likely to benefit from the intervention. It is certainly a misconception to view gains in life expectancy as increments of time tacked onto the end of a fixed life span. Life expectancy can be estimated from empirical data by a variety of methods that each have strengths and weaknesses.

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Longevity in Specific Populations

T.T. Samaras , in International Encyclopedia of Public Health, 2008

Worldwide Variations in Life Expectancy

Life expectancy is the average age at death for a particular population group. Note that life expectancies are also determined for each age group, usually in 10-year increments.

Life expectancies are available for 225 populations ranging from China to the tiny sovereign states of Andorra and San Marino. As shown in Table 1 , life expectancies at birth for males and females combined range from 33.23   years for Swaziland to 83.52   years for Andorra (Central Intelligence Agency, 2007).

Consistent with findings that a good environment and SES promote longevity, most of the longest living populations are found in highly developed populations with superior sanitation, education, and health care. The worst life expectancies are found in Africa with its lower economic development and very high rate of mortality from HIV/AIDS infection. The top ten populations in terms of descending life expectancy (83.52 to 80.59   years) are Andorra, Macao, Japan, Singapore, San Marino, Hong Kong, Sweden, Australia, Switzerland, and France. (Rankings shift from year to year but most of these states stay in the top ten or close to it.)

The low life expectancy of developing populations does not mean that elderly people are absent from developing populations. Since poor countries tend to have much higher infant death rates, this situation lowers the average life expectancy. In addition, early deaths of children and young adults due to malnutrition, trauma, and infections reduce the average life expectancy. However, if early death is avoided, adults often reach advanced ages (Walker, 1974; Samaras, 2007).

A common misconception in comparing today's life expectancy to that of earlier times, such as the 1900s, is the belief that individuals can expect to live 25–30   years longer. However, if we look at the life expectancy of elderly people, the picture is quite different; e.g., 60-year-old white males lived 6.6   years longer in 2004 vs 1900, and 80-year-olds lived 3   years longer.

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Active Life Expectancy

K.G. Manton , in International Encyclopedia of Public Health, 2008

Active life expectancy, the average number of years a person can expect to live without chronic disability, is a better measure of the health status of populations in economically developed countries than total life expectancy because the latter has reached levels where most early deaths have been prevented and large survival increases are now likely only at later ages. It is important to assess whether such life expectancy increases are associated with improved quality of life, the capability for independent living, and continued economic activity. Active life expectancy calculations are illustrated with recent disability data from the United States.

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Longevity of Specific Populations

Thomas Theodore Samaras , in International Encyclopedia of Public Health (Second Edition), 2017

Worldwide Variations in Life Expectancy

Life expectancy is the median age at death for a particular population group. For example, if a group of people have a life expectancy at birth of 70  years, half died before 70 and half survived beyond this age. Note that life expectancies are also determined for each age group, usually in 10-year increments.

Life expectancies are available for over 200 populations ranging from China to the tiny sovereign states of Andorra and San Marino. As shown in Table 1, life expectancy at birth for males and females combined range from 33.22   years for Swaziland to 83.51   years for Andorra (Wikipedia, 2006).

Consistent with findings that a good environment and SES promote longevity, most of the longest living populations are found in highly developed populations with superior sanitation, education, and health care. The worst life expectancies are found in Africa with its lower economic development and very high rate of mortality from HIV/AIDS infection. The top 10 populations in terms of descending life expectancy (83.51–80.42   years) are Andorra, Macau, San Marino, Singapore, Hong Kong, Japan, Sweden, Switzerland, Australia, and Guernsey (UK). (Depending on the year, the ranking varies somewhat, but has essentially remained unchanged over the last 15   years).

The low life expectancy of developing versus developed populations does not mean that elderly people are absent from developing populations. Since poor countries tend to have much higher infant death rates, this situation lowers the average life expectancy. In addition, early deaths of children and young adults due to malnutrition and infections reduce the average life expectancy. However, if early death is avoided, adults often reach advanced ages (Walker, 1974; Samaras, 2007, 2013).

A common misconception in comparing today's life expectancy to that of earlier times, such as the 1900s, is the belief that individuals can expect to live 25–30   years longer. However, if we look at the life expectancy of elderly people, the picture is quite different; e.g., 60-year-old white males could expect to live 6.6   years longer in 2004 versus 1900, and 80-year-olds could live 3   years longer. This is a small increase in view of the exceptional health and medical developments over the last century. Our workweek has also declined from about 60 to 40   h per week with increased worker safety and benefits.

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Life Expectancy and Adult Mortality in Industrialized Countries

T. Valkonen , in International Encyclopedia of the Social & Behavioral Sciences, 2001

Life expectancy at birth increased rapidly in industrialized countries from 1950 to 1970 mainly as a result of the decline in mortality from infectious diseases brought about by the introduction of antibiotics. The increase in life expectancy continued after 1970 in market economy countries. This was mainly attributable to the decline in mortality from cardiovascular diseases among middle-aged and elderly people. In the former socialist countries the increase almost ended. Female life expectancy is higher than male life expectancy in all countries, but the size of the difference varies. The sex differential increased in practically all countries from the 1950s to the late 1970s, but then started to diminish in Northern and Western Europe, North America, and Oceania, where the average difference was approximately six years in the 1990s. The lower life expectancy of men is due partly to biological and partly to behavioral factors. Persons in lower socioeconomic positions die on average at a younger age than those in higher positions. This difference is smaller among women than men. The socioeconomic mortality gap seems to have increased in many countries since the 1970s, due to the more rapid decline in mortality from cardiovascular diseases among persons in nonmanual than manual occupations.

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Introduction

Jiben Roy , in An Introduction to Pharmaceutical Sciences, 2011

1.2.1 The impact of pharmaceutical industries on human lives

Life expectancy throughout the world increased from an average of 30–40 years in the early twentieth century to an estimated 66.12 years in 2009. 7 In the USA, life spans increased from an average of 47 years in 1950 to 78.06 years today, and US life expectancy continues to grow (Figure 1.12).

Figure 1.12. US life expectancy in the USA, 1950–2007

 Source: Department of Health and Human Services, CDC, US, and Innovation.org 8

Research data suggest there is a correlation between life expectancy and the development of the pharmaceutical industry. Using aggregate time series data, Dr Frank R. Lichtenberg, a researcher at Columbia University, studied the impact of new drug approval by the US Food and Drug Administration (FDA) on US lifespan longevity. The results show that a 40% increase in life expectancy can be attributed to new medicines (Figure 1.13). According to another study, by innovation.org and the Pharmaceutical Research and Manufacturers of America (PhRMA), the new drugs reduce the risk of death (Figure 1.14).

Figure 1.13. Life expectancy in more and less developed regions of the USA, 1950/55–1995/2000

 Source: Frank R. Lichtenberg 9

Figure 1.14. Total increase in longevity compared with increase in longevity resulting from new medicines, USA, 1988–2000

 Source: Frank R. Lichtenberg 10

Alan Sheppard of IMS Health made an effective correlation between life expectancy and drug use in an aging Europe after collecting data from the United Nations and an IMS market prognosis (Figure 1.15).

Figure 1.15. Correlation between life expectancy and drug expenditure per capita in Europe, 2005–2010

 Source: IMS Heath 11

The effect that drugs have in countering disease is exemplified by data on HIV/AIDS cases. In the 1980s there were only one or two drugs available to treat AIDS patients, but the number and availability of newer medicines increased dramatically since 1996, when highly active antiretroviral treatment (HAART) was introduced, which had an immediate effect (Figure 1.16).

Figure 1.16. Mortality rate 1995–2007, showing effect of introducing highly active antiretroviral treatment in 1997 for AIDS patients in the USA

 Source: PhRMA 12

During the last decade, the US FDA approved more than 300 new medicines in various disease categories, for example cancer and cardiovascular disease, which have increased patients' survival rates and longevity, and decreased disability.

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Lipids and Cardiovascular Diseases: Epidemiologic Perspectives

T. Okamura , ... A. Hirata , in Encyclopedia of Cardiovascular Research and Medicine, 2018

Introduction

Average life expectancy in ancient Greek and Roman times was 27 years in 200–300BC. By the year AD1900, it had increased to 47 years. Thus, life expectancy had increased by only 20 years during more than 2000 years. However, looking back to the end of the 20th century, life expectancy had increased by a further 30 years in a mere century as a consequence of the control of epidemic diseases, treatment of infections with antibiotics, vaccination, and improvements in food and environmental safety. Prolongation of life expectancy more recently has been due mostly to prevention of cardiovascular disease (CVD), and for many years plasma cholesterol has been recognized as one of its most important risk factors.

This article reviews aspects of lipids and CVD from the viewpoint of epidemiology, from the first epidemiologic studies to recent clinical trials.

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Novel treatment strategies for neurodegenerative disease with sirtuins

Kenneth Maiese , in Sirtuin Biology in Medicine, 2021

1.1 Increased life expectancy and neurodegenerative disease

Life expectancy is increasing throughout the world. In the United States, life expectancy was decreasing over a 4-year period. However, with a recent reduction in deaths from opioid overdoses, life expectancy is increasing again in the United States [1]. At present, life expectancy has reached 80 years of age [2]. From the years 2000 through 2011, the age-adjusted death rate for life expectancy has been marked by a 1% decrease [3]. Over the prior 50 years, it is estimated that the number of people over the age of 65 has doubled [4]. It is predicted that large countries such as China and India will see an increase in the elderly population from 5%–10% over multiple decades [5,6]. Interestingly, the 10 leading causes of death—cardiac disease, cancer, trauma, respiratory disease, stroke, Alzheimer's disease (AD), diabetes mellitus (DM), influenza and pneumonia, kidney disease, and suicide—continue to remain the same [1]. A number of reasons can account for the observed increase in life span [7]. These include enhanced access to preventive medical care, improved public health guidelines and sanitation measures, and new treatments for multiple disease entities for both mental and physical health [8–16].

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Population Diversity and Pharmacogenomics in Africa

Collen Masimirembwa , ... Julia Hasler , in Handbook of Pharmacogenomics and Stratified Medicine, 2014

Life Expectancy and Age Distribution

Life expectancy has an impact on the proportions of different age groups in a population. Africa shows the greatest diversity in this regard, with life expectancy in some countries at 47–55  years of age and others greater than 70   years. Other regions in the world are more uniform in terms of life expectancy, which averages around 70–80 [22,23]. In planning for stratified medicine in the future, different regions of the world will have to take into account the age proportions in their populations. Burden of disease and ensuing healthcare needs vary considerably depending on the profile of the different age groups. In the future, while most of the world will have to cater to a large extent to the health needs of those over 60   years of age, African countries will likely be more diverse in this regard [24].

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