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Life Expectancy

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Meaning of Life Expectancy

Life Expectancy meaning is an estimation of the average number of additional years that an individual of a given age can expect to live. Life expectancy at birth is the most commonly used indicator of life expectancy. Life expectancy is a speculative metric. It is assumed that the age-specific mortality rates for the year in question would apply to persons born in that year for the rest of their lives. In effect, the forecast predicts the age-specific mortality (death) rates for a given period over the entire lifespan of the population born (or alive) during that time period. The measure varies greatly depending on gender, age, race, and geographic place. As a result, life expectancy is often provided for individual groups rather than the general population. For example, females born in 2003 in the United States have a life expectancy of 80.4 years.

Life expectancy is affected by local conditions. Life expectancy at birth is lower in less-developed countries than in more-developed countries. Because of high child mortality rates, life expectancy at birth may be lower in some less-developed countries than life expectancy at age one (commonly due to infectious disease or lack of access to a clean water supply).

Life expectancy is mathematically represented as the average number of years of life remaining at a given age, assuming age-specific mortality rates remain at their most recently measured levels. It is denoted by ex, which stands for the average number of subsequent years of life for those currently aged x based on a specific mortality experience. Longevity, maximum lifespan, and life expectancy are not synonyms. The average number of years remaining for a person or a group of people at a given age is known statistically as life expectancy. Longevity refers to the features of certain members of a population having a relatively long lifespan. The maximum lifespan of a species is the age at which the longest-lived individual dies. Furthermore, since life expectancy is average, a person's death could occur several years before or after the "anticipated" survival. The word "full lifespan" refers to longevity and has a completely different definition.

Life Expectancy Rate

A life table is used to measure life expectancy. A life table contains data on age-specific death rates for the population in question, which requires enumeration data for the population's population size and the number of deaths at each age. These numbers are usually derived from the national census and vital statistics data, and they can be used to measure the average life expectancy for each age group within the population.

The accuracy of estimated life expectancy is dependent on the completeness of census and death data for the population in question. The extent to which the data is complete varies by region. Since 1900, in conjunction with the decennial census, official full life tables based on recorded deaths have been prepared in the United States. Since 1945, annual abridged U.S. life tables based on annual death registration and population projections have been released. Abridged life tables show life expectancy for 5 or 10-year age groups rather than single-year groups, while complete life tables show life expectancy for any year of age.

Another method of calculating life expectancy is healthy life expectancy (or disability-free life expectancy), which is the average number of years an individual is expected to live in good health or without disability, given current age-specific mortality rates and disease and disability prevalence rates. Calculating such figures necessitates the use of accurate health statistics, as well as mortality and census results.

Differences in Life Expectancy Across the World

As we have seen in the concept of life expectancy rates above, let us now analyse life expectancy around the world. Life expectancy is an indicator of premature death that reveals significant differences in health around the world. Many of the world's richest countries' populations have life expectancies of more than 80 years. Life expectancy in Spain, Switzerland, Italy, and Australia was over 83 years in 2019. Japan had the longest life expectancy, at nearly 85 years. Life expectancy in the poorest countries ranges between 50 and 60 years. In 2019, the Central African Republic has the lowest life expectancy at 53 years.

Life expectancy is rising in the majority of countries. Although the contribution of various causes of death and age groups has changed over time, the overall pattern of life expectancy growth appears to be very stable. The successes in reducing mortality and improving lifespan are varied. For long-term changes in life expectancy in countries with low healthcare spending, such as Japan, a mix of strategies is needed to introduce efficient and cost-effective prevention interventions while also improving social conditions.

Rising Life Expectancy Around the World

Life expectancy in the pre-modern, poor world was about 30 years in all regions of the world. The estimates by historian James Riley shown here indicate that there was some difference between different world regions, but life expectancy was well below 40 years in all world regions.

The historical estimates are fraught with uncertainty; it is worthwhile to read Riley's work to appreciate the estimates' limitations and strengths. However, these questions are much outweighed by the dramatic rise in life expectancy since then.

Infectious diseases devastated the world, and as we demonstrate in our entry on infant mortality, almost half of all children died before reaching adulthood. Those that did survive mostly died shortly after. Diseases were killing most people at a young age in the absence of public health programmes and effective medicines.

Until recently, this was humanity's truth. For much of history, life expectancy in each area of the world remained remarkably constant until mankind began to make strides against poor health just a few generations ago. The era when life expectancy started to rise significantly is referred to by epidemiologists as the "health transition."

Factors Affecting Life Expectancy

Longevity has improved over the last century as a result of medical advances and lifestyle changes. Not only has the average life expectancy risen since 1900, but a greater number of people are aged to older ages, thanks in part to a steep decrease in the early 1900s' high infant mortality rate.

The following are nine factors that can influence mortality and longevity:

1. Gender

Female mortality rates are lower than male mortality rates at all ages, according to the Institute and Faculty of Actuaries. On average, women live longer than men. According to several reports, this difference is due in part to men's riskier attitudes, which could contribute to higher accident rates.

2. Genetics

A link between genetic factors and mortality rates appears to exist. According to the Centers for Disease Control, genetics may play a role in nine of the top ten causes of death. According to the Centers for Disease Control and Prevention, the following are the leading causes of death in the United States:

  • Heart disease

  • Cancer

  • Chronic lower respiratory disease

  • Accidents

  • Stroke or cerebrovascular disease

  • Alzheimer’s disease

  • Diabetes

  • Influenza and pneumonia

  • Kidney disease

  • Intentional self-harm or suicide

3. Prenatal and Childhood Conditions

According to IFA, poor conditions in utero, at birth, and in very early childhood are associated with higher mortality even at advanced ages. The Society of Actuaries has been researching the effect of early childhood factors on exceptional longevity, such as whether growing up in a city or farm community influences longevity and whether growing up in different geographic areas is correlated with different life expectancies.

4. Education

According to an analysis, higher education levels are associated with higher socioeconomic status, and both are associated with enhanced longevity.

According to the CDC, life expectancy at 25 improved by 1.9 years for men and 2.8 years for women with a bachelor's degree or higher. A 25-year-old man without a high school diploma has a 9.3-year lower life expectancy than a man with a bachelor's degree or higher. According to the CDC, women with a high school diploma have a life expectancy of 8.6 years less than their peers with a bachelor's degree or higher.

According to CDC results, higher education levels were also associated with lower levels of obesity and tobacco use, which may correlate with greater longevity.

5. Socio-economic Status

According to the IFA, when one's socioeconomic status declines, so does one's life expectancy. Socioeconomic status, among other things, can influence a person's ability to obtain proper medical care and their involvement in safe lifestyle behaviours such as exercising more, smoking less, and maintaining a healthy weight.

6. Marital Status

According to IFA, married people have lower mortality rates than those who were never married, divorced, or widowed. Various studies indicate that marriage or committed relationships can improve cardiac health, help combat isolation and loneliness, which can have a negative impact on mental health, and encourage people to make healthier choices such as maintaining frequent doctor visits and quitting bad habits.

7. Ethnicity/Migrant Status

Ethnicity and migrant status can also be linked to socioeconomic status. According to IFA, migrant mortality tends to vary as a result of variations in average mortality between host and home countries, as well as healthy selection for migration or return and duration of stay in the host country.

8. Lifestyle

Historically, unhealthy diets, insufficient exercise, tobacco usage, excessive alcohol use, unsafe habits, food protection, occupational safety, and motor vehicle safety have all been linked to increased mortality. Obesity is also the most significant lifestyle factor influencing mortality.

9. Medical Technology

Medical and technological advancements have had a major effect on improved longevity. Antibiotics and immunizations, as well as advances in imaging, surgery, cardiac treatment, and organ transplantation, have all contributed to an increase in average life expectancy.

Evolution and Aging Rate

The lifespans of various plant and animal species, including humans, vary. According to evolutionary theory, species that live for long periods of time and avoid accidents, illness, predation, and so on are more likely to have genes that code for slow ageing, which also translates to good cellular repair. According to one hypothesis, if predation or premature deaths preclude the majority of people from surviving to old age, there would be less natural selection to increase the inherent life span. 

One well-known and widely accepted theory holds that limiting one's food energy budget, known as caloric restriction, will increase one's lifespan. Caloric restriction, which has been found in many species (most notably mice and rats), results in a nearly doubling of life span from a relatively small caloric intake. Several new studies linking lower basal metabolic rate to improved life expectancy have added to the theory's support. That is why animals like giant tortoises can live for so long. Humans with life expectancies of at least 100 years have been shown to have lower thyroid function, which results in a lower metabolic rate.

Healthy Life Expectancy

For the last 30 years, 'healthy life expectancy' has been measured to measure the quality of these extra years of life. Since 2001, the World Health Organization has released Healthy life expectancy (HALE) statistics, which are described as the average number of years an individual may expect to live in "full health," excluding years spent in less than full health due to disease and/or injury. Since 2004, Eurostat has released annual statistics based on recorded activity limitations known as Healthy Life Years (HLY). Similar metrics are used in the United States as part of the national health promotion and disease prevention strategy "Healthy People 2010." Life expectancy indicators are being used by an increasing number of countries to measure the health of their populations.

In the 2010s, the long-standing search for longer life gave way to a more promising emphasis on increasing HALE, also known as a person's "healthspan." Aside from the advantages of keeping people alive for longer, one aim is to reduce healthcare costs associated with the many diseases associated with cellular senescence. Fasting, exercise, and senolytic drugs are among the approaches being investigated.


Forecasting life expectancy and mortality is a crucial subset of demography. Future trends in life expectancy have significant implications for old-age welfare services such as Social Security and pensions in the United States since the cash flow in these schemes is determined by the number of recipients who are still alive (along with the rate of return on the investments or the tax rate in pay-as-you-go systems). Longer life expectancy increases cash outflow; if systems underestimate increases in life expectancy, they would be unprepared for the massive payments that will arise as humans live longer and longer.

Life Expectancy vs. Maximum Life Span

Life expectancy is often confused with the average age at which an adult would expect to die. This ambiguity will lead to the presumption that an adult is unlikely to outlive an average life expectancy, despite the fact that an adult who has already escaped many statistical causes of adolescent mortality should be expected to outlive the average life expectancy measured from birth. To measure an adult's life expectancy, one must equate the life expectancy of the period following childhood. Even in preindustrial times, life expectancy can change significantly after childhood, as shown by the Roman Life Expectancy table, which predicts life expectancy to be 25 years at birth but 53 years at age 25. Similarly, studies such as Plymouth Plantation; "Dead at Forty" and Life Expectancy by Age, 1850–2004 indicate a significant rise in life expectancy once adulthood is reached.

Life expectancy is not the same as the maximum life span. Life expectancy is an average for the whole population, including those who die shortly after birth, those who die in early adulthood (e.g., childbirth, war), and those who live unhindered until old age. Maximum lifespan is an individual concept; hence, maximum lifespan is an upper limit rather than an average. Christopher Wanjek, a science author, said "Has the human race's lifespan increased? No, not at all. This is one of the most common myths about old age." The maximum life span, or the oldest age at which a person may live, can be fixed.


As we define Life Expectancy, it is mathematically represented as the average number of years of life remaining at a given age. The age-specific death rates for the year in question are considered to refer to people born in that year for the rest of their lives. Local factors influence life expectancy. Longevity refers to the characteristics of members of a population that have a relatively long lifespan. A species' maximum lifespan is the age at which the longest-living organism dies. The term "full lifespan" refers to longevity and has a completely different definition of life expectancy rate. The population of many of the world's wealthiest countries has a life expectancy of more than 80 years. In 2019, the average life expectancy in Spain, Switzerland, Italy, and Australia was more than 83 years. With a life expectancy of nearly 85 years, Japan had the highest. The Central African Republic had the lowest life expectancy in 2019, at 53 years.

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FAQs on Life Expectancy

1. What is Life Expectancy in the Us and the World?

Ans: Before COVID, the average life expectancy in the United States was 78.7 years, and the world's current life expectancy in 2021 is 72.81 years, a 0.24 percent rise from 2020. The world's life expectancy in 2020 was 72.63 years, a 0.24 percent rise from 2019.

2. What Do You Mean by Life Expectancy or What is the Meaning of Life Expectancy?

Ans: Life Expectancy meaning is an estimation of the average number of additional years that an individual of a given age can expect to live. Life expectancy at birth is the most commonly used indicator of life expectancy. Life expectancy is a speculative metric. It is assumed that the age-specific mortality rates for the year in question would apply to persons born in that year for the rest of their lives.

3. What's the Life Expectancy Rate of India?

Ans: The life expectancy rate of India was 69.42 years in 2018.