ageing. The WHO is championing a global strategy and action plan to promote a healthy ageing environment for older adults worldwide. This action plan's goals include creating age‐friendly environments to support older adults in their communities, align national healthcare systems with the needs of an ageing population, and supporting research to measure, monitor, and understand the global ageing process.
In the United States, the number of adults over 65 grew 30% between 2010 and 2018, to 12.2 million people. Older adults now make up 16% of the total population, and this proportion is expected to grow, such that by 2050, one in every five people in the US will be 65 or older (www.census.gov).
Older adults in the US are also becoming more diverse. As of 2017, approximately 23% of adults over 65 belonged to racial and ethnic minorities, and this number is projected to increase to 34% by 2050.2 This demographic shift is driven primarily by immigration, both by people who immigrated to the US at a young age and will remain here the rest of their lives and a smaller number who immigrated in older adulthood. Asians and Hispanics are expected to see the largest relative growth.3 See the section “Geographic considerations: migration and immigration” for more information about the older adult migrant experience.
The causes of population ageing
Increases in life expectancy around the world have led to absolute ageing of the global population. Improved sanitation, nutrition, and living conditions, as well as major healthcare innovations such as effective treatments for infectious diseases, vaccinations, and advances in neonatal care, have led to significant advances in global life expectancy and increases in the absolute number of people who live to old age. In 1950, the average life expectancy was 49 years (68 in developed countries), as compared to 72 (79 in developed countries) in 2019 (www.un.org).
Management of chronic diseases, particularly cardiovascular and oncologic diseases, has also led to extended life expectancy in adulthood and older age. The United Nations projects modest increases in lifespan through the next several decades, although due to biologically and physiologically fixed mechanisms, it seems unlikely that, as a species, human life expectancy will ever exceed approximately 115 years of age.4
Declining fertility rates are also leading to a phenomenon of relative ageing, or an increased proportion of older adults. Data from the United Nations demonstrates declining fertility rates globally due to various factors, including improved access to birth control, declining numbers of teenage pregnancies, increased female engagement in the workforce, a higher percentage of women pursuing advanced education, and delays in the average age of marriage. The decline in fertility rates is more pronounced in developed countries, but the trend is seen globally.
Figure 4.1 The societal and community factors that influence an older adult's health and well‐being are complex.
Old‐age dependency ratio
As both the absolute number and relative proportion of the population over the age of 65 increase, this will impact the old‐age dependency ratio: an economic index defined as the number of people age 65 or older per 100 people of working age (15–64 years old).
The socioeconomic implications of this rising ratio are an area of active research and debate. Implications include increased spending on healthcare, Social Security, disability, pensions, and infrastructure to support an ageing population, with fewer wage‐earners contributing taxes. An increased proportion of older adults also calls for a greater need for healthcare spending and long‐term care employees who can provide care for those who are disabled from advanced age and/or chronic illness. However, this ratio is an imperfect measure. It does not account for adults who work past the age of 65 or improvements in care and advances in technology that reduce the societal burden of ageing and disability. Although the old‐age dependency ratio will certainly increase globally, the economic and societal implications remain uncertain.
Gender imbalance
At birth, the male to female birth rate is approximately 1.05:1. However, females generally have a longer life expectancy than males, which leads to a shifting of the gender ratio in older adults, such that females outnumber males. There are many proposed reasons for longer female life expectancy. Biologically, oestrogen may be protective against cardiovascular disease. Additionally, women are less susceptible to X‐linked genetic disorders. Males are more likely to engage in high‐risk behaviour, including dangerous occupations, reckless driving, and substance use. Historically, political upheaval and wartime have disproportionately affected men. For example, the fall of the USSR and resulting political prosecutions led to a profound gender gap in modern‐day Russia, resulting in an almost 11‐year discrepancy in male life expectancy compared to females.5 Finally, behavioural science suggests women generally engage with medical care and seek medical attention earlier than men, possibly leading to earlier diagnosis and treatment of common conditions.6 As mortality from cardiovascular disease improves, and as women engage in the workforce and high‐risk behaviours like smoking at increasing rates, the gender gap in older adults is expected to narrow.7
According to date from the UN, in the US, as of 2020, females outnumber males at a ratio of 1.1:1 at age 65, 1.2:1 at 75, 1.5:1 at 85, and 2.5:1 at 95. These ratios are projected to decline by 2050, such that the male to female ratio in adults age 65 will equalize, however females will continue to outnumber males at older ages but to a lesser degree (Figure 4.2). In the US, there is also a fair amount of regional variability. The ratio of females to males is much less in rural counties, particularly in the Western part of the country (excluding California), possibly due to male migration for occupational reasons.7
In much of the developed world, gender ratios of older adults are similar to those in the US. In developing countries, due to less access to education and healthcare, higher rates of physical abuse, and risk of poverty in widowhood, women have lower life expectancies, resulting in female to male ratios closer to 1.1 India and China, which have historically practised female infanticide, have significantly more males than females, and these effects extend into older adulthood.
Approximately 0.5% of adults over 65 identify as transgender in the United States.8 Transgender older adults face a unique set of challenges, including cumulative effects of a lifetime of discrimination, and generally report higher rates of anxiety, depression and loneliness and less robust support networks than age‐matched peers. There is also a dearth of cultural competency training for providers of older adults around issues of gender and sexual identity. Additional information on LGBT+ older adults can be found in Chapter 5.
Geographic considerations: migration and immigration
In the United States, approximately 13.5% of the population over 65 is foreign‐born.9 Of those, three of four are naturalized citizens. Foreign‐born older adults are significantly less likely to speak English at home; approximately half of foreign‐born older adults reported to the US Census that they speak English ‘less than very well.’ This is an important consideration for providers working with older adults, as it could have major impacts on their ability to navigate the complex American healthcare system.
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