The “Graying” Population and Life Expectancy

Diana Lang; Nick Cone; Martha Lally; Suzanne Valentine-French; and Sonja Ann Miller

The term “graying of America” refers to the fact that the American population is steadily becoming more dominated by older people. In other words, the median age of Americans is going up.[1] According to the U.S. Census Bureau’s 2017 National Population Projections (Figure 1), the year 2030 marks an important demographic turning point in U.S. history. By 2030, all baby boomers will be older than age 65. This will expand the size of the older population so that 1 in every 5 residents will be retirement age. And by 2035, it’s projected that there will be 76.7 million people under the age of 18 but 78 million people above the age of 65. [2]

United States population data by age group from the U.S. Census Bureau that show population in 1960 as a pyramid shape (wide base, narrow top) with the largest population groups being between 0 and 4 years old, 5 and 9 years old, and 10 and 14 years old. The number of people in age groups decreases as ages rise above forty to forty five years, showing the age group eighty-five plus years old being the smallest population. In contrast, the projected ages for the year 2060 show a pillar-like shape instead of a pyramid, with roughly similar numbers of children, adults, and elderly.
Figure 1. 2030 marks an important demographic change as international migration is expected to overtake natural population increases in the United States. (Image Source: U.S. Census Bureau)

The 2030s are projected to be a transformative decade for the U.S. population. The population is expected to grow at a slower pace, age considerably and become more racially and ethnically diverse. Net international migration is projected to overtake natural increase in 2030 as the primary driver of population growth in the United States, another demographic first for the United States.

Although births are projected to be nearly four times larger than the level of net international migration in coming decades, a rising number of deaths will increasingly offset how much births are able to contribute to population growth. Between 2020 and 2050, the number of deaths is projected to rise substantially as the population ages and a significant share of the population, the baby boomers, age into older adulthood. As a result, the population will naturally grow very slowly, leaving net international migration to overtake natural increase as the leading cause of population growth, even as projected levels of migration remain relatively constant.[3]

“Graying” Around the World

While the world’s oldest countries are mostly in Europe today, some Asian and Latin American countries are quickly catching up. The percentage of the population aged 65 and over in 2015 ranged from a high of 26.6 percent for Japan to a low of around 1 percent for Qatar and United Arab Emirates. Of the world’s 25 oldest countries, 22 are in Europe, with Germany and Italy leading the ranks of European countries for many years.[4]

By 2050, Slovenia and Bulgaria are projected to be the oldest European countries. Japan, however, is currently the oldest nation in the world and is projected to retain this position through at least 2050. With the rapid aging taking place in Asia, the countries of South Korea, Hong Kong, and Taiwan are projected to join Japan at the top of the list of oldest countries and areas by 2050, when more than one-third of these Asian countries’ total populations are projected to be aged 65 and over.[5]

Life Expectancy

Life expectancy is a statistical measure of the average time an organism is expected to live, based on the year of birth, current age and other demographic factors including gender. The most commonly used measure of life expectancy is at birth (LEB). There are great variations in life expectancy in different parts of the world, mostly due to differences in public health, medical care, and diet, but also affected by education, economic circumstances, violence, mental health, and sex.

Life Expectancy vs Lifespan

Lifespan or Maximum Lifespan is referred to as the greatest age reached by any member of a given population (or species). For humans, the lifespan is currently between 120 and 125. Life Expectancy is defined as the average number of years that members of a population (or species) live. According to the World Health Organization (WHO)[6] global life expectancy at birth in 2015 was 71.4 years, with females reaching 73.8 years and males reaching 69.1 years. Women live longer than men around the world, and the gap between the sexes has remained the same since 1990. Overall life expectancy ranged from 60.0 years in the WHO African Region to 76.8 years in the WHO European Region. Global life expectancy increased by 5 years between 2000 and 2015, and the largest increase was in the WHO African Region where life expectancy increased by 9.4 years. This was due primarily to improvements in child survival and access to antiretroviral medication for the treatment of HIV. According to the Central Intelligence Agency[7] the United States ranks 43rd in the world for life expectancy.

Gender Differences in Life Expectancy

Biological Explanations

Biological differences in sex chromosomes and different pattern of gene expression is theorized as one reason why females live longer.[8] Males are heterogametic (XY), whereas females are homogametic (XX) with respect to the sex chromosomes. Males can only express their X chromosome genes that come from the mother, while females have an advantage by selecting the “better” X chromosome from their mother or father, while inactivating the “worse” X chromosome. This process of selection for “better” genes is impossible in males and results in the greater genetic and developmental stability of females. In terms of developmental biology, women are the “default” sex, which means that the creation of a male individual requires a sequence of events at a molecular level.

Men are more likely to contract viral and bacterial infections, and their immunity at the cellular level decreases significantly faster with age. Although women are slightly more prone to autoimmune and inflammatory diseases, such as rheumatoid arthritis, the gradual deterioration of the immune system is slower in women.[9][10]

Looking at the influence of hormones, estrogen levels in women appear to have a protective effect on their heart and circulatory systems.[11] Estrogens also have antioxidant properties that protect against harmful effects of free radicals, which damage cell components, cause mutations, and are in part responsible for the aging process. Testosterone levels are higher in men than in women, and are related to more frequent cardiovascular and immune disorders. The level of testosterone is also responsible, in part, for male behavioral patterns, including increased levels of aggression and violence.[12][13] Another factor responsible for risky behavior is the frontal lobe of the brain. The frontal lobe, which controls judgment and consideration of an action’s consequences, develops more slowly in boys and young men. This lack of judgment affects lifestyle choices, and consequently many more boys and men die by smoking, excessive drinking, accidents, drunk driving, and violence.[14]

Lifestyle Factors

Certainly not all the reasons women live longer than men are biological. As previously mentioned, male behavioral patterns and lifestyle play a significant role in the shorter lifespans for males. One significant factor is that males work in more dangerous jobs, including police, firefighters, and construction, and they are more exposed to violence. According to the Federal Bureau of Investigation[15] there were 11,961 homicides in the U.S. in 2014 (last year for full data) and of those 77% were males. Males are also more than three times as likely to commit suicide.[16] Further, males serve in the military in much larger numbers than females. According to the Department of Defense,[17] in 2014 83% of all officers in the Services (i.e., Navy, Army, Marine Corps and Air Force) were male, while 85% of all enlisted service members were male.

Additionally, men are less likely than women to have health insurance, develop a regular relationship with a doctor, or seek treatment for a medical condition.[18] As mentioned in the middle adulthood chapter, women are more religious than men, which is associated with healthier behaviors.[19] Lastly, social contact is also important as loneliness is considered a health hazard. Nearly 20% of men over 50 have contact with their friends less than once a month, compared to only 12% of women who see friends that infrequently.[20] Overall, men’s lower life expectancy appears to be due to both biological and lifestyle factors.


According to Kane,[21] older men and women are often viewed as genderless and asexual. There is a stereotype that elderly individuals no longer engage in sexual activity and when they do, they are perceived to have committed some kind of offense. These ageist myths can become internalized, and older people have a more difficult time accepting their sexuality.[22] Additionally, some older women indicate that they no longer worry about sexual concerns anymore once they are past the childbearing years.

In reality, many older couples find greater satisfaction in their sex life than they did when they were younger. They have fewer distractions, more time and privacy, no worries about getting pregnant, and greater intimacy with a lifelong partner.[23] Results from the National Social Life Health, and Aging Project indicated that 72% of men and 45.5% of women aged 52 to 72 reported being sexually active.[24] Additionally, the National Survey of Sexual Health data indicated that 20%-30% of individuals remain sexually active well into their 80s.[25] However, there are issues that occur in older adults that can adversely affect their enjoyment of healthy sexual relationships.

Causes of Sexual Problems

According to the National Institute on Aging,[26] chronic illnesses including arthritis (joint pain), diabetes (erectile dysfunction), heart disease (difficulty achieving orgasm for both sexes), stroke (paralysis), and dementia (inappropriate sexual behavior) can all adversely affect sexual functioning. Hormonal changes, physical disabilities, surgeries, and medicines can also affect a senior’s ability to participate in and enjoy sex. How one feels about sex can also affect performance. For example, a woman who is unhappy about her appearance as she ages may think her partner will no longer find her attractive. A focus on youthful physical beauty for women may get in the way of her enjoyment of sex. Likewise, most men have a problem with erectile dysfunction (ED) once in a while, and some may fear that ED will become a more common problem as they age. If there is a decline in sexual activity for a heterosexual couple, it is typically due to a decline in the male’s physical health.[27]

Overall, the best way to experience a healthy sex life in later life is to keep sexually active while aging. However, the lack of an available partner can affect heterosexual women’s participation in a sexual relationship. Beginning at age 40 there are more women than men in the population, and the ratio becomes 2 to 1 at age 85.[28] Because older men tend to pair with younger women when they become widowed or divorced, this also decreases the pool of available men for older women.[29]

  1. Most of this chapter was adapted from select chapters in Lumen Learning's Lifespan Development, authored by Martha Lally and Suzanne Valentine-French available under a Creative Commons Attribution-NonCommercial-ShareAlike license. The section on the "graying" of America is from Waymaker Lifespan Development, authored by Sonja Ann Miller for Lumen Learning, and is available under a Creative Commons Attribution-ShareAlike license. Some selections from Lumen Learning were adapted from previously shared content from Laura Overstreet's Lifespan Psychology and Wikipedia.
  2. US Census Bureau. (2018, October 05). Population Projections.
  3. US Census Bureau. (2018, December 03). Older People Projected to Outnumber Children.
  4. Wan, H., Goodking, D., and Kowal, P. (2015). An Aging World: 2015. United States Census Bureau.
  5. Wan, H., Goodking, D., and Kowal, P. (2015). An Aging World: 2015. United States Census Bureau.
  6. World Health Organization. (2016). Life expectancy.
  7. Central Intelligence Agency. (2016). The world factbook. world-factbook/geos/xx.html
  8. Chmielewski, P., Borysławski, K., & Strzelec, B. (2016). Contemporary views on human aging and longevity. Anthropological Review, 79(2), 115–142.
  9. Caruso, C., Accardi, G., Virruso, C., & Candore, G. (2013). Sex, gender and immunosenescence: a key to understand the different lifespan between men and women? Immunity & Ageing: I & A, 10(1), 20.
  10. Hirokawa, K., Utsuyama, M., Hayashi, Y., Kitagawa, M., Makinodan, T., & Fulop, T. (2013). Slower immune system aging in women versus men in the Japanese population. Immunity & Ageing: I & A, 10(1), 19.
  11. Viña, J., Borrás, C., Gambini, J., Sastre, J., & Pallardó, F. V. (2005). Why females live longer than males: control of longevity by sex hormones. Science of Aging Knowledge Environment: SAGE KE, 2005(23), e17.
  12. Martin, P., Poon, L. W., & Hagberg, B. (2011). Behavioral factors of longevity. Journal of Aging Research, 2011, 197590.
  13. Borysławski, K., & Chmielewski, P. (2012). A prescription for healthy aging. In: A Kobylarek (Ed.), Aging: Psychological, biological and social dimensions (pp. 33-40). Wrocław: Agencja Wydawnicza.
  14. Shmerling, R. H. (2016). Why men often die earlier than women. Harvard Health Publications.
  15. Federal Bureau of Investigation. (2014). Crime in the United States. u.s/2014/crime-in-the-u.s.-2014/tables/expanded- homicide- data/expanded_homicide_data_table_1_murder_victims_by_race_ethnicity_and_sex_2014.xls
  16. Centers for Disease Control and Prevention. (2016a). Increase in Suicide in the United States, 1999–2014.
  17. Department of Defense. (2015). Defense advisory committee on women in the services. %20Report_Final.pdf
  18. Scott, P. J. (2015). Save the Males. Men’s Health.
  19. Greenfield, E. A., Vaillant, G. E., & Marks, N. F. (2009). Do formal religious participation and spiritual perceptions have independent linkages with diverse dimensions of psychological well-being? Journal of Health and Social Behavior, 50, 196-212.
  20. Scott, P. J. (2015). Save the Males. Men’s Health.
  21. Kane, M. (2008). How are the sexual behaviors of older women and older men perceived by human service students? Journal of Social Work Education, 27(7), 723-743.
  22. Gosney, T. A. (2011). Sexuality in older age: Essential considerations for healthcare professionals. Age Ageing, 40(5), 538-543.
  23. National Institutes of Health. (2013). Hypothyroidism. topics/endocrine/hypothyroidism/Pages/fact-sheet.aspx
  24. Karraker, A., DeLamater, J., & Schwartz, C. R. (2011). Sexual frequency declines from midlife to later life. The Journal of Gerontology, Series B: Psychological Sciences and Social Sciences, 66B, 502-512.
  25. Schick, V., Herbenick, D., Reece, M., Sanders, S. A., Dodge, B., Middlestadt, S. E., & Fortenberry, J. D. (2010). Sexual behaviors, condom use, and sexual health of Americans over 50: Implications for sexual health promotion for older adults. Journal of Sexual Medicine, 7(5), 315-329.
  26. National Institutes of Health. (2013). Hypothyroidism. topics/endocrine/hypothyroidism/Pages/fact-sheet.aspx
  27. Erber, J. T., & Szuchman, L. T. (2015). Great myths of aging. West Sussex, UK: John Wiley & Sons.
  28. Karraker, A., DeLamater, J., & Schwartz, C. R. (2011). Sexual frequency declines from midlife to later life. The Journal of Gerontology, Series B: Psychological Sciences and Social Sciences, 66B, 502-512.
  29. Erber, J. T., & Szuchman, L. T. (2015). Great myths of aging. West Sussex, UK: John Wiley & Sons.


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The “Graying” Population and Life Expectancy by Diana Lang; Nick Cone; Martha Lally; Suzanne Valentine-French; and Sonja Ann Miller is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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