Mohammed T. Abou-Saleh

Principles and Practice of Geriatric Psychiatry.Editors: Professor John R. M. Copeland, Dr Mohammed T. Abou-Saleh and Professor Dan G. BlazerCopyright & 2002 John Wiley & Sons LtdPrint ISBN 0-471-98197-4 Online ISBN 0-470-84641-090 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYDemography of the Old: Implications of Recent TrendsEmily GrundyLondon School of Hygiene and Tropical Medicine, London, UKIn most developed countries, at least 10% and in some cases morethan 15% of the total population is aged 65 and over 1 . Recentprojections suggest that by 2025 the proportion aged 75 and overwill lie in this range; by then people aged 65 and over willcontribute a quarter of the total in a number of countriesincluding Japan, Italy and Greece, and over one-fifth in most ofthe rest of Europe. The proportion of ‘‘oldest old’’—those aged 85years or more—is increasing particularly rapidly 2 . As the risk ofdementia is so strongly age-related, these changes will mean alarge increase in the numbers affected unless strategies forprevention and postponement can be identified and implemented.However, there are also other implications of current demographictrends. Here I focus on changes in mortality andsurvivorship and also consider briefly changes in marriage.The initial impetus for this ageing of the human world camefrom the transition to lower fertility that was set in motion inmany Western populations in the last quarter of the nineteenthcentury and is now close to being a global phenomenon. Morerecently, the pace of population ageing, and the ageing of elderlypopulations, has been accelerated by marked declines in late agemortality; these are now the predominant motor driving thefurther ageing of populations with already old age structures 3 .The extent of this change is illustrated for five developedcountries in Table 1. In England and Wales, France and the USA,Table 1 Further expectation of life at age 65, 1900–19951900–1901 1950–1951 1970–1971 1995MenEngland and Wales 10.1 10.8 11.9 14.8France 10.0 12.2 13.0 16.1Japan 10.1 10.9 12.5 16.5Sweden 12.1 13.5 14.3 16.0USA 11.4 12.8 13.1 15.3WomenEngland and Wales 11.1 13.4 15.8 18.4France 10.9 14.6 16.8 20.6Japan 11.4 13.0 15.4 20.9Sweden 13.0 14.3 16.9 19.7USA 12.0 15.1 17.1 19.2Data from: Government Actuary’s Department, Berkeley.Mortality Database (http://demog.berkeley.edu/wilmoth/mortality); and the JapaneseMinistry of Health and Welfare.Table 2 Survival to age 80 by birth cohort, Englandand WalesYear of birth Survival to age 80 (%)Men Women1861 10 161881 14 251901 17 341921* 29 47*Partly based on projections.Source: Author’s analysis of data from the GovernmentActuary’s Department.male expectation of life at age 65 increased as much or morebetween 1970 and 1995 than in the preceding 70 years (or indeed,in the case of England and Wales, in the preceding century 4 ).Among women too, the extent of improvement since 1970 isnotable. Viewed from a cohort perspective, increases in longevityappear even more remarkable. Table 2 shows the proportion ofeach birth cohort surviving to the age of 80. Survival to later olderage has increased dramatically reflecting not only large improvementsin infant and child mortality (still very high in thenineteenth century) but also the more recent improvements inlate adult death rates. Today, women of 80 represent not a selectgroup of elite survivors, but half their original birth cohort. Theseimprovements are not confined to the ‘‘young’’ elderly; death ratesamong the oldest old, including centenarians, have also droppedsubstantially 5,6 .These changes have sparked fierce debate about possiblechanges in the relationship between mortality and morbidity,the plasticity of the ageing process, possible limits to longevityand, of course, implications for health services. Less frequentlyconsidered are the implications for the family and supportnetworks of older people and how these may interact with otherchanges in, for example, marriage and partnership.The gender differences in mortality apparent in the tablesunderlie one of the most notable features of the older population,the preponderance of women. In the UK in 1998 the ratio ofwomen to men at age 60–64 was close to parity (1.04) but rose to1.85 at age 80–84 and 3.5 in the 90–94 year-old group. Oneconsequence of this gender imbalance, compounded by thecommon pattern of women marrying men older than themselves,is that 65% of women aged 75 and over are widows, while 62% ofmen of this age are still married. If the narrowing of sexdifferentials in mortality continues, as is projected, the proportionof widows in this group will fall to 52% by 2021; however, by then10% will be divorced (compared with 3% now) and a much largerproportion will have experienced divorce at some point in theirlives (21% of those born in 1950 had already experienced divorceby the age of 40 7 ). Those who have experienced marital disruptionhave poorer health in early old age 8 , although this may be becauseof factors associated with both risk of divorce and poor health.Changes in the age structure of populations also mean changein the age structure of families. Lower mortality increases theavailability and duration of ‘‘vertical’’ kin networks. A recent(1999) national survey showed that 74% of people aged 80 andover in Britain were members of three-generation families andover one-third had living children, grandchildren and greatgrandchildren9 . Contacts between older people and their childrenand grandchildren are frequent; however, there have been verylarge decreases in the extent of intergenerational co-residence. In1991 21% of women aged 85 and over lived in two- or threegenerationalhouseholds, compared with 42% 20 years earlier 10 .During the same period (1971–1991) the proportion of olderpeople moving to institutions increased, while the proportionmoving to live with relatives fell, suggesting some substitution ofthe former for family care 11 .Demographic changes of the type and magnitude, which here Ihave had space to allude to only briefly, require some thinkingabout roles, relationships and activities throughout the life course.