Population Ageing from a Lifecourse Perspective

Critical and International Approaches

Komp, Kathrin, Johansson, Stina

• Publisher: Policy Press
• Year: 2016
• ISBN:
  9781447334385
• Topic: Social Sciences
• Subtopic: Gerontology
• Index: Social Sciences

Populations around the globe are ageing rapidly. This demographic shift affects families, market structures and social provisions. This timely volume, part of the Ageing and the Lifecourse series, argues that the lifecourse perspective helps us understand the causes and effects of population ageing. The lifecourse perspective suggests that individuals' experiences at an early age can influence their decisions and behaviour at a later age. This much-needed volume combines insights from different disciplines and real-life experiences to describe the theories and practices behind this idea. It therefore caters to the needs of scholars, practitioners and policy makers in a range of areas including sociology and political science.

Part I

THEORETICAL FRAMEWORK

TWO

A demographer’s view: population structures tell a story about lifecourses

J. Scott Brown and Scott M. Lynch

Introduction

Demography is the study of populations, with populations commonly defined as: persons living within a geographic boundary who tend to share a common language and culture. Traditionally, demographers have focused on the three sources of change – the ‘population dynamics’ – that influence the size and growth or decline of populations. Change in the components of population dynamics, at least as observed in human populations, inevitably lead to population ageing and have tremendous consequences for the lifecourse of individuals. In this chapter, we describe population dynamics and explain how they lead to population ageing, illustrating the complex and varying means by which populations age. We then discuss the consequences for the individual lifecourse, and we offer suggestions for incorporating demographic reasoning into micro-level lifecourse research.

Population dynamics

Population size is influenced by three factors: births into the population, deaths out of the population, and net migration, where net migration is the sum of migration into the population (immigration) and migration out of the population (emigration). The fundamental ‘balancing equation’ in demography demonstrates how population change occurs:

Pt = P{t–k} + B{t–k,t} – D{t–k,t} + NM{t–k,t}, (1)

where Pt is the population size at time t, P{t–k} is the population size at time t – k, B{t–k,t} is the number of births in the population between t-k and t, D{t-k,t} is the number of deaths in the population between t – k and t, and NM{t–k,t} is the net migration into the population between t – k and t. If Pt > P{t–k}, then the population is growing over time; if Pt < P{t–k}, then the population is declining; if Pt = P{t–k}, then the population is stable (Preston et al, 2000).

Historically, most populations in the world have grown over time because births have tended to outpace deaths, and this is especially so in societies prior to the 20th century. Eventually, as countries become more developed, via agricultural and industrial revolutions, most countries experience a demographic transition (Thompson, 1929). A demographic transition is marked by declining death rates, followed by declining fertility rates, inevitably leading to both rapid population growth and a change in the population’s age structure. The decline in death rates leads to population growth because more persons survive to later ages than before – in particular, at least initially, more persons survive beyond one year of age.

We can conceptualise pre-transition populations’ age structures as pyramids, with a broad base of younger persons and a top that tapers, reflecting fewer and fewer persons at older and older ages. When both fertility and death rates decline, the population pyramid ‘rectangularises’, reflecting a more uniform distribution of the population into age ranges.

Figures 2.1 and 2.2 illustrate rectangularisation and the population ageing process at different stages of the demographic transition. Figure 2.1 shows the population pyramid for Benin in 2013, a country that has not yet experienced a demographic transition. Benin’s population pyramid is very triangular in shape, with the majority of the nation’s population being in the younger age groups. Indeed, there are more persons in Benin under six years of age than there are persons over the age of 50. Figure 2.2, in contrast, shows the population of the United States (US) in 2013, a nation that completed its demographic transition in the early 20th century. This population pyramid is much more rectangular in shape except for the very oldest age groups. For example, the US population has about the same number of persons in the age groups nearing retirement (meaning in their 50s and early 60s) as the number of persons who are children and adolescents.

Figure 2.1: Population of Benin by gender, 2013

Figure 2.2: Population of the United States by gender, 2013

Population dynamics and population ageing

The consequence of declining mortality and fertility is population ageing, and it is often illustrated in one of two ways: (1) as an increase in the mean and/or median age of persons in the population; and/or (2) as an increase in the proportion of the total population that falls in an arbitrarily defined ‘old’ age group, such as above age 60, 65 or even 85. While these two measures of population ageing appear to reflect the same process, they do not. They may stem from very different combinations of the dynamics underlying the balancing equation.

Most, if not all, developed societies are ageing, but the population dynamics underlying population ageing are complex and varied across societies. Population ageing can result from changes in any of the three components of the balancing equation, as well as combinations therein. Most, if not all, developed societies, for example, have experienced an ‘epidemiologic transition’ following their general demographic transition. Epidemiologic transitions are marked by fundamental changes in the relative incidence of different causes of death (Omran, 1971). Early on within developed societies, there is a transition from predominantly agriculture-based economies to predominantly industrial economies, and fertility rates fall but death rates remain relatively constant. At that stage, deaths stem from infectious and related acute causes as well as accidents (especially for males working in industrial locations). Such causes may be relatively evenly distributed across the age range, or they may hit the ends of the age distribution the hardest, that is, the youngest and the oldest. Infant and child mortality are often high, and few persons live long enough to die from ‘old-age’ diseases that require accumulation of exposure, such as heart disease, cancer and stroke. Eventually, however, with implementation of widespread public health measures like waste removal, sewage treatment, water purification and vaccination, along with advances in medical practice, including, for example, the development and use of antibiotics, most acute causes of death decline in incidence. Additionally, work-related deaths also decline somewhat as these societies impose workplace safety practices and regulations. Individuals, therefore, become more likely to live well into middle and late adulthood, and chronic disease death rates increase. The net result is that the population grows mostly at older ages, because fertility rates continue to decline while death rates in old age remain relatively flat or decline slightly (see McKeown, 2009, for a detailed discussion of the theory of epidemiologic transition and its critiques). A second epidemiologic transition has tended to follow the first in many developed societies in which death rates due to chronic conditions have fallen as such diseases have been pushed off to later and later in life (for example Lamb and Myers, 1993). Thus, fertility rates remain low and death rates at older ages plummet, thereby accelerating population ageing.

In short, population ageing can occur due to change in mortality at either end of the age distribution, and with or without changes in fertility, although most societies experience both significant fertility decline and reductions in mortality throughout the age range. Reductions in fertility increase the average age in the population by reducing the proportion of the total population in younger age groups. In that situation, the proportion of a population that is in older age groups increases, but only relatively, because of the reduction in the numbers of persons at younger ages, and the average age of the population increases as well. Reductions in childhood mortality increase the average age of the population, because of the survival of persons into older – but still young – age groups. Thus, in that situation, the average age increases, while the proportion of the population in the oldest age groups may be unaffected. Reductions in old age mortality may increase the average age of the population, but they do not have to, if fertility increases. For that matter, such reductions do not necessarily imply an increase in the proportion of the population in the oldest age groups. In other words, population ageing may be measured in different ways, but measures are not necessarily correlated, because ageing may occur in very different fashions, and therefore have very different implications for the lifecourse, as we discuss later.

In addition to changes in fertility and mortality dynamics, migration can – and does – play a substantial role in population ageing, and its influence is even more complex across societies. Of the three elements of demographic change, migration is often the least emphasised in terms of population ageing. Nevertheless, migration between populations can have a tremendous effect on the age structure of populations receiving migrants as well as on the age distribution of those nations from which individuals emigrate. This is largely due to the tendency for migrants to be working-age adults. Indeed, the United Nations estimates that almost 75% of all migrants worldwide in 2010 were of any adult working age (meaning between 18 and 65), and more than 50% of all migrants were between age 20 and age 50 (United Nations, 2011). This age pattern of migration results in a slowing of population ageing in the receiving country, while at the same time accelerating population ageing within the sending nation. For example, Germany is a relatively old country, with about 20% of its population over the age of 65 in 2011. Turkey on the other hand is a relatively young country, with an age 65+ population of only about 7% in 2011. However, migration between these two nations has been substantial, with Germany receiving a large number of typically young adult Turkish immigrants over the last three to four decades such that around three million persons of Turkish descent now reside in Germany (more than 3%). Given that these immigrants were overwhelmingly working-age adults, this migration has resulted in a somewhat younger age structure in Germany than there would have been otherwise and a somewhat older age structure in Turkey. In other words, the difference in population ageing between these two nations would be more substantial except for the migration between their populations.

Similarly, in the US, a society which is ageing rapidly, both in terms of the mean age increasing and the proportion of the total population in the oldest age groups, the influx of Mexican migrants has served to slow the rate of population ageing. Although debates over immigration policy have often mentioned the potential negative consequences of both legal and illegal Mexican migration in terms of reducing wages and consuming health care and social assistance resources, such migration has, in fact, served to slow the rate of population ageing, because migrants tend to be of working ages. Despite the fact that migrants tend to help ‘anchor’ illegal immigrants’ families in the US, and some family members are elders who may draw social security and Medicare benefits, the net result is a larger working-age population. At the same time that immigration from Mexico into the US reduces the rate of ageing for the US, it simultaneously increases the rate of ageing in Mexico. More insidiously, most migration, regardless of location, tends to involve movement of healthy persons (Palloni and Arias, 2004). As a result, Mexican migration into the US has served to reduce ageing and improve the health of the US population, while simultaneously increasing ageing and worsening the health of the Mexican population.

This migration effect on population health and ageing is not limited to migration that crosses national borders. Indeed, the same process is occurring within national boundaries, as migration from rural to urban locations is common. For example, in Thailand, due in large part to economic reasons, Bangkok draws substantial immigration from the rural countryside. Much like the international migration shown in the examples of Mexico and Turkey mentioned earlier, these migrants are predominantly working-age adults. Thus, this internal migration tends to slow population ageing in the urban areas of Thailand, while at the same time accelerating ageing in Thai rural areas – a migration and ageing pattern that is fairly common among developing nations. This internal migration pattern also occurs in developed nations, but with the added complexity of retirement migration. That is, in developed nations like the US, it is not uncommon for individuals, on retiring, to migrate. In the US, this migration is often unidirectional to southern states that offer a warmer climate and commonly a lower cost of living. Thus, this migration can alter the age structure of these areas that receive migrating retirees. But this is only one part of the story. It is also common in these developed nation contexts for retirees who have migrated, should they become significantly ill, to return to their native area to receive care (and perhaps caregiving from family that still live in those areas). In other words, internal migration has a very complex relationship with population ageing, where it can slow ageing in some areas, increase ageing in other areas with only modest effects on health, and increase ageing in yet other areas while also worsening the overall...

Table of contents

• Cover
• Title Page
• Copyright
• Contents
• List of tables and figures
• Notes on the contributors
• Foreword: Judith Phillips
• One: Introduction: Kathrin Komp and Stina Johansson
• Part I: Theoretical framework
• Part II: Critical perspectives
• Part III: Practical implications
• Part IV: Discussion and conclusion