An Aging World – demographics and challenges

Abstract

The world has seen enormous changes over the past century, including historically unprecedented declines in mortality rates and increases in population, followed by equally unprecedented declines in fertility rates. This century will see a new set of demographic challenges, including a mix of falling fertility rates alongside persisting worldwide population growth, and the subsequent aging of populations in both developing and developed countries. The 20th century was the century of population growth; the 21st century will go into the history books as the century of aging. A holistic approach to this new challenge of the 21st century will necessitate a quantum leap in multidisciplinary and internationally coordinated research efforts, supported by a new partnership between industry and governments, philanthropic and international organizations. This collaboration we hope will enrich us with a better understanding of healthy aging, permit us to help to improve quality of life, prevent the preventable, and postpone and decrease the pain and suffering of the inevitable.

Keywords:

• Aging
• life expectancy
• health expectancy
• fertility rate
• birth rate
• health aging

In the year 1500 the global population was around 400 million people. Population showed rapid growth in the 17th and 18th centuries and stood at 1 billion at the start of the 19th century; then 1.6 billion at the beginning of the 20th century, and now, at the first decade of the 21st century, it has reached 6 billion.

The estimates and projections of the United Nations indicate that between 1900 and 2100, world population will increase sevenfold, from 1.65 billion to 11.5 billion: an increase of almost 10 billion people [1]. During the last century, life expectancy at birth increased by more than 30 years. Better hygiene and public sanitation in the 19th century and the use of pesticides, modern medicine and antibiotics in the 20th century led to expanded life expectancy, resulting in quicker population growth, primarily in developed countries. Demographic transition in the 19th and 20th centuries was the result of shifts from high to low mortality and a significant decrease of fertility rates [2]. The birth rate in about a third of the world's nations has slipped below the two-child replacement level. In 1970, there were 22 countries with total fertility rate at or below the replacement of 2.1. In the year 1999 there were 68 countries, and it is projected that by 2020, 121 countries – representing 75% of the global population – will have birth rates below the replenishment level [3]. Owing to this low birth rate the overall population of the EU is projected to decrease between 2006 and 2050 by 9%, in spite of a net annual migration rate of 2/1000. Natural increase (the ratio of births over deaths) will turn negative for the EU in 2010. And the vast majority of Europe's countries – including Belgium, the Czech Republic, Germany, Italy, Poland and Russia – are projected to lose population in the next 25 years [4]. Japan will have a population decrease of 25% between 2006 and 2050 [1] (Table I).

Table I.  Demographic data, 2006

Region	Population (millions)				Fertility rate (%)	Life expectancy (years)		Net annual migration* (per 1000)	Change^†, 2006–2050 (%)
	1950	2006	2025	2050		M	F
World	2520	6555	7940	9243	2.7	65	69	0	41
Africa	224	924	1355	1994	5.1	51	53	0	116
North America	166	332	387	462	2.9	75	81	4	39
South America	111	378	465	525	2.4	69	76	−1	40
Asia	1437	3968	4739	5277	2.4	66	70	0	33
China	563	1311	1476	1437	1.6	70	74	0	10
Japan	84	127	121	100	1.3	79	86	0	−21
Europe	547	732	717	665	1.4	71	79	2	−9

Source: International database 2006 (US Census Bureau), World population data sheet (Population Reference Bureau; www.prb.org). M, males; F, females; *net annual migration is derived as a residual from estimated birth, death and population growth rates; ^†projected percentage population change between 2006 and 2050.

As a consequence of the decreased fertility rate and the increased life expectancy at birth, by 2050 – for the first time in human history – there will be more people over the age of 65 than under the age of 15. The population of persons above 65 years old will increase from 400 million to 1.5 billion during the same time period. The proportion of oldest-old (those aged 80 years and older) will increase from 1.9% to 4.2%. The population of centenarians in 2050 will be 16 times larger than in 1998 (2.2 million compared with 135 000).

In 2002, there were in Europe some four persons in the working age group per one person aged 65 years; it is projected by the United Nations that, by 2050, these figures will be reduced to as low as two (in Europe) and even one (in Italy). Hence, for the Brave New World of future Italy, it is projected that – by the year 2050 – there will only be one person in the working age group for each person aged 65 years or older. There is no historical precedent for such low potential support ratios. How will society function with such an age distribution? [5].

With the lengthening of life expectancy at birth, non-communicable diseases and associated disability received increasing importance. Consequently the need for a new type of indicator, namely ‘health expectancy’: ‘disability-free life expectancy’, ‘healthy life expectancy’ or ‘active life expectancy’, became necessary. The introduction of the concepts of the International Classification of Impairments, Disabilities and Handicaps by the World Health Organization in 1980 allowed the efficient use of health expectancy indicators. It appears that the last 8–11 years of our life are accompanied by some kind of disability (Table II).

Table II.  Health expectancy data, 2005

	Health expectancy at birth (years)		Life expectancy (years)	Loss of healthy years
	Mean	Range
USA	65.7	63.8–67.5	76.4	10.7
Italy	69.5	68.4–70.8	80.6	11.1
UK	68.3	66.8–69.7	76.8	8.5
Japan	71.2	69.9–72.5	79.6	8.4
China	60.9	59.5–62.5	70.5	9.7
France	68.5	67.4–69.5	78.6	10.2
Germany	67.4	66.0–68.7	76.6	9.2
Singapore	66.8	64.3–69.0	78.1	11.3
Sweden	70.1	68.7–71.6	79.2	9.2
Switzerland	70.4	68.7–72.1	79.3	8.8

Source: International database 2005 and the US Census Bureau.

With all the rhetoric surrounding the impending ‘age quake’ produced by the ‘graying of the world’, there has been surprisingly little serious analysis of the social and economic implications of increased longevity. Increasing longevity, declining birth rate and migration patterns are creating major demographic changes in developed and developing countries alike (Table III). These changes present profound challenges to the world's social and economic systems and call into question some basic assumptions about continued prosperity and economic growth.

Table III.  Demographic changes, 2006–2050

	Population aged 60 years or older
	2006		2050
Region	(millions)	% of total	(millions)	% of total
World	688	11	1964	22
North America	57	17	118	27
Asia	375	9	1227	24
Europe	151	21	225	34
Africa	48	5	192	10

Source: United Nations publication, ST/ESA/SER.A/245 and international updates (to September 2005). Demographic trends regarding the issue of aging underscore the fact that both current situations and future trends directly concern all of us. Aging is the reality for the future world. The pace at which demographic transition develops varies among countries and regions of the world, but most of the developed and developing countries will be challenged by increasing numbers of dependent individuals. This is particularly critical in the less-developed countries where older populations will increase substantially faster.

Since the last years of life are accompanied by an increase of disability and sickness, the demands on social and health services will increase immensely. The high cost in relation to these services will strain to the limit the potential ability of the health, social and even political infrastructures not only of developing countries, but also of the most developed and industrialized nations. Less developed countries – which have much lower levels of economic development and access to adequate healthcare than more developed countries – will be hard-pressed to meet the challenges of more elderly people, especially as traditional family support systems for the elderly are breaking down. Policy-makers in the developing world need to invest soon in formal systems of old-age support to be able to meet these challenges in the coming decades. To prudent healthcare administrators, the establishment of preventive measures, rather than concentration on interventive care, is an important strategic thrust in overall management of the aging population. Since frailty, disability and dependency will increase immensely the demand on social and health services, the ability to permit people to age gracefully and maintain independent living, free of disability, for as long as possible is a crucial factor in aging with dignity and would furthermore reduce health service costs significantly. To achieve this objective, a holistic approach to the management of aging has to be adopted.

The promotion of healthy aging and the prevention, or drastic reduction, of morbidity and disability among the elderly must assume a central role in the formulation of health and social policies. It must emphasize an all-encompassing, lifelong approach to the aging process beginning with pre-conceptual events and focus on appropriate interventions at all stages of life.

Life-history studies of childhood and adolescence demonstrate clearly that social factors probably operate in a cumulative fashion. There are significant social class differences in attainment of height growth and other aspects of physical development, as well as in incidence of infectious and other diseases and risk of injury. Cross-sectional studies show differences in mortality and morbidity as a function of socio-economic status, across various disease categories, throughout the life span. Poverty has a significant impact on both life and health expectancy. It should not only be measured in terms of property, employment, wages and income, but also in terms of basic education, healthcare, nutrition, water and sanitation. Educational attainment and marital status have also been shown in several longitudinal studies to be powerful predictors of morbidity, health expectancy and mortality [6]. The economic consequences of retirement place many older citizens in positions of financial vulnerability. As populations age, in both the developing and developed worlds, the issue becomes how to keep older persons economically viable within their respective societies. No community is exempt from the financial hardships experienced by aging populations. The remarkable demographic transformations in the past century have not only led to increased medical needs of older people, who often have multiple chronic conditions, decrements in functional ability and age-related disease, but also to the increase of social expenditures, such as pension funds and health insurance, to support them. The life-course perspective leads to important policy and strategy decisions [7]. A complementary approach to improving the health of older men and women should focus on appropriate interventions at all stages of their lives. The determinants of ‘aging’ and of ‘life expectancy’ extend from genetic and molecular determinants to the increasingly powerful forces of environmental, economical, technological and cultural globalization. Specific measures for the promotion of healthy aging should therefore include:

1. The promotion of a safe environment;

2. Healthy lifestyle including proper nutrition;

3. Appropriate exercise;

4. Avoidance of smoking;

5. Avoidance of drug and alcohol abuse;

6. Social interactions to maintain good mental health;

7. Preventive medical strategies to delay, decrease or prevent frailty and disabilities;

8. Medical healthcare including the control of chronic illnesses.

If done effectively, the above measures should result in an increase in the quality of life with a delay, decrease or prevention of disabilities. This would increase length of productive life of aging populations, decrease dependency, and as a result decrease health costs related to expensive curative and palliative services. The medical profession, pharmaceutical and health industries will need to be prepared to face up to these challenges. A holistic approach to this new challenge of the 21st century will necessitate a quantum leap in multidisciplinary and internationally coordinated research efforts, supported by a new partnership between industry and governments, philanthropic and international organizations. This collaboration we hope will enrich us with a better understanding of health and aging, permit us to help to improve quality of life, prevent the preventable, and postpone and decrease the pain and suffering of the inevitable.