Editorials
doi: 10.1111/1753-6405.12357
Could we all live to 100? Should we? Alistair Woodward, School of Population Health, University of Auckland, New Zealand
Tony Blakely Department of Public Health, University of Otago Wellington, New Zealand
T
he beginning of the year is traditionally the time for reflecting on how things have gone in the past, and making resolutions about what lies ahead. Here we review one measure of public health success, life expectancy, and look ahead to what may, and should, be achieved in the future. When the first issue of Community Health Studies, the forerunner of this journal, was published in 1977, average life expectancy at birth was 73.4 years in Australia and 72.6 years in New Zealand. The most recent figures, for 2012, are 82.6 and 82.1 years, respectively: in other words, during this journal’s existence average life expectancy in our countries has increased every year by about three months, rather faster in fact for men.
We are seeing a remarkable and underappreciated transformation in human prospects. When Captain Cook landed in New Zealand in 1769, life expectancy in England was in the low 30s; for Māori we estimate the figure was in the high 20s.1 World-wide, average life expectancy has more than doubled in about five generations.2 In the long history of our species, such a change is unprecedented. Death rates have fallen so far that the difference between human hunter-gatherers and the lowest-mortality modern populations is greater, according to one estimate, than the difference in survival between hunter-gatherers and wild chimpanzees.3 The predominant causes of mortality decline vary depending on the time period and the location. In New Zealand, the trajectories have been different for Māori and non-Māori, and what has benefited the latter has to some extent been at the cost of the former. The early, world-leading good health of the European section of the New Zealand population, for instance, was due in large part to the rapid transfer of land and other natural resources from Māori to non-Māori in the second half of the 19th century. Other factors
2015 vol. 39 no. 1
that may have contributed to the rise in life expectancy for non-Māori up to 1940 include: health selection of migrants; lack of crowding and urban pollution that held back mortality improvements in Europe; egalitarian social policies (so that non-Māori at least benefited maximally from opportunities for social development); early initiatives to extend education and promote the position of women; and the economic opportunities that New Zealand enjoyed when it acted as grocer to the British Empire.1 For Māori, we estimate that life expectancy at birth fell to a low point of 20 years or less close to the end of the 1800s, and then rebounded so fast that the gap between Māori and non-Māori was almost halved by 1940. The major forces behind the decline and recovery of indigenous health were poverty and cultural loss, reflected in high fatality from tuberculosis and other infectious diseases, followed by social and, probably, biological adaptation to the new colonial-era disease regime, and this recovery was amplified by political organisation, public health interventions and all-round improvements in living conditions. The major players in the New Zealand mortality stakes in the second half of the 20th century were effective medical treatments (which accelerated the long-term reduction in infectious disease, and more recently slashed mortality from many chronic conditions), the epidemic of cardiovascular disease that stalled life expectancy improvement amongst men for almost 20 years, the tobacco blight that took hold most tenaciously on Māori women, and socially regressive economic policies in the 1980s and 1990s that for a time stretched health inequalities. The story of human life expectancy in Australia differs from the New Zealand experience in some respects. Migration patterns have been different, for example. This brought, we speculate, less advantage
to Australia in the 19th century when the healthy migrant effect acted less forcefully than it did in New Zealand, and greater benefits in the 20th century (when dietary preferences imported from southern Europe contributed to Australia’s speedier recovery from the epidemic of heart disease). However, the similarities are more important than the differences. We note the impact of colonial settlement on Aboriginal health, the mid-20th century transition from infectious to chronic diseases, the predominance of period effects on mortality trends, and improvements in the last 20 years that elevated both countries into the top band of longevity, internationally.4 Where will this lead? A simple linear extrapolation of recent trends implies that average life expectancy in Australia and New Zealand will exceed 100 years before 2100. Will this really happen? Our view is it is unlikely, but not impossible, that we will get to a century by 2100. Unlikely, because it becomes more and more difficult to squeeze out extra years of life expectancy as mortality shrinks.5 Also there is little room in high life span countries for further improvement amongst the young: in the future, substantial gains in life expectancy will depend on relentless reductions in mortality in the oldest age groups. According to one estimate, to reach an average life expectancy of 100 in Australia it would be necessary to reduce the mortality rates that applied in the early 1990s by more than 90%.6 It seems intuitive that there are physical limits to how long the human machinery can keep running. But many commentators have claimed in the past that the improvement in life expectancy is about to hit the ceiling, and they have been proven wrong – life expectancy has kept rising.7 Also, there is no sign we are presently close to biological or social limits on mortality decline, and for these reasons it would be unwise, in our view, to rule out a life expectancy of 100 or more at some time in the future. The longest-lived population in the world, Japanese women, steadily continues its yearon-year improvement in life expectancy.8 Death rates in the oldest age groups continue to tumble, in many countries. Amongst men, New Zealand and Australia are ranked 1 and 2 in the world in terms of average annual increase in life expectancy at age 60 since 1980.9 There are substantial, avoidable causes of mortality in New Zealand and Australia that
Australian and New Zealand Journal of Public Health © 2015 Public Health Association of Australia
3
Editorials
can and should be overcome. To that extent future life expectancy gains, or at least the possibility of future gains, are ‘baked in’. The New Zealand government has committed to reducing smoking prevalence to less than 5% by 2025: if this was achieved life expectancy for Māori would be lifted by about 5 years, and non-Māori by three years, compared to what would apply if the smoking rates in 2006 continued unabated. In our assessment, the gains that can and should be made from the reduction of smoking will exceed the negative impacts of rising body weight.1 Also, both New Zealand and Australia are held back by inequalities in mortality by ethnicity and social status. We estimate that if New Zealand could flatten its socio-economic gradient to the extent that mortality rates of the most deprived quintile of the population were only 15 per cent higher than those in the least deprived quintile, then life expectancy at birth would be boosted by 2-3 years. Note also that recent improvements are not due entirely to the ‘compression of mortality’ (i.e. postponing deaths till some fixed upper limit on life expectancy, which would imply rapidly diminishing gains in the future). There is another force at play – the extension of maximum longevity, which stretches the survival curve to the right, and indicates that further large improvements may still occur. An analysis of European data found that longevity extension was responsible for about 60% of the increase in life expectancy between 1922 and 2006.10 It is unlikely in the foreseeable future that everyone will receive a congratulatory tweet from the Monarch, but the number of people living past 100 years will increase significantly. Remember the standard period life expectancy figures (such as those we cited earlier) assume no future reductions in age-specific mortality. If recent mortality trends continue, Statistics New Zealand estimates that a male born in 2011 will live on average 90.2 years (90% CI 86.3-94.0) and a female 92.9 years (89.3-96.2).11 If this happens, it is likely the median age at death will be creeping up into the mid 90s, and the number of centenarians will multiply. Is this a future we should desire, and strive for? Quality of life is the red flag that everyone raises: it may not be a good thing to live longer if the extra years are spent in poor health. So far, the rise in life expectancy has generally been associated with improvements in the all-round health and functioning of older people, but trends
4
are not clear-cut, not least because of the difficulties in defining, measuring and monitoring good health. In New Zealand, it is estimated that about two-thirds of the years of extra life that have been gained since 1996 have been years without disability, but the time spent living with disability has increased since survival has advanced more quickly than morbidity has retreated.12 From some countries there are reports of an expansion in poor health; at issue is whether states of ill-health are consistently measured and reported over time.13 Looking ahead, it is not certain whether future cohorts of the very old will be more or less resilient than present-day survivor populations. On the one hand, quality of life is clearly not fixed by age and exceptional longevity does not necessarily bring with it excessive levels of disability.14 But the combination of older individuals and older populations will almost certainly deepen the morbidity pool and, as a consequence, raise the demand for health and social services. Whether a world in which we all live to 100 is affordable depends on the scope, cost and effectiveness of health and social services. It depends also on how we view ageing, define productivity, and conceive of ‘affordability’. There are risks. Radical ageing might block opportunities for the young, and lead to social stasis in a conservative, elder-dominated society. On the other hand, better health might enable more people to stay in the workforce longer and, formal employment aside, to be socially productive in many other ways, as volunteers for example. Demographic change may have other advantages: better-educated and longer-lived populations may be more environmentally parsimonious, for example.15 The decline in mortality is a crude and partial indicator of progress in population health, but it cannot be overlooked. Huge changes have occurred; further improvements will be made. Whether life expectancy will reach 100 is not clear, although it would be every cricketer’s model of a ‘good innings’. The present direction in New Zealand and Australia suggests this particular milestone is not out of reach. One can always make a case that other social goals should trump greater longevity. But that has not led, in the past, to serious dis-investment in life-prolonging interventions, and we don’t forsee any change: the collective urge to live longer and look around the next corner is too strong. We anticipate instead difficult and contested
trade-offs, between age groups, generations, and desired outcomes. In this respect, 2015 and the years that follow will resemble closely those that have preceded.
References 1. Woodward A, Blakely T. The Healthy Country? A History of Life and Death in New Zealand. Auckland: Auckland University Press; 2014. 2. Riley J. Estimates of Regional and Global Life Expectancy, 1800–2001. Popul Dev Rev. 2005 Sep 17;31:537–43. 3. Burger O, Baudisch A, Vaupel JW. Human mortality improvement in evolutionary context. Proceedings of the National Academy of Sciences. 2012 Oct 30;109(44):18210–4. 4. Taylor R, Lewis M, Powles J. The Australian mortality decline: all-cause mortality 1788–1990. Aust NZ J Publ Heal. 1998;22(1):27–36. 5. Olshansky SJ. Can a lot more people live to one hundred and what if they did? Accident Anal Prev; 2013 Dec 1;61:141–5. 6. Mathers C, Douglas B. Measuring progress in population health and wellbeing. In: Eckersley R, editor. Measuring Progress. Is Life Getting Better? Melbourne: Collingwood; 1998: 125-156. 7. Oeppen J, Vaupel J. Broken limits to life expectancy. Science. 2002;296(5570):1029–31. 8. Ikeda N, Saito E, Kondo N, Inoue M, Ikeda S, Satoh T, et al. What has made the population of Japan healthy? Lancet; 2011 Sep 17;378(9796):1094–105. 9. Mathers CD, Stevens GA, Boerma T, White RA, Tobias MI. Causes of international increases in older age life expectancy. Lancet. Published Online November 6, 2014. http://dx.doi.org/10.1016/ S0140-6736(14) 60569-9 10. Rossi IA, Rousson V, Paccaud F. The contribution of rectangularization to the secular increase of life expectancy: an empirical study. Int J Epidemiol. 2012 Dec 21;42(1):250–8. 11. Woods C, Dunstan K. Forecasting mortality in New Zealand. Wellington: Statistics New Zealand; 2014. 12. Ministry of Health and Statistics New Zealand. Longer life, better health? Trends in health expectancy in New Zealand 1996–2006. Wellington: Statistics New Zealand; 2009 13. Robine J-M, Saito Y, Jagger C. The relationship between longevity and healthy life expectancy. Quality in Ageing and Older Adults. 2009 Jun 14;10(2):5–14. 14. Christensen K, McGue M, Petersen I, Jeune B. Exceptional longevity does not result in excessive levels of disability. Proceedings of the National Academy of Sciences. 2008;105:13274-9. 15. Kluge F, Zagheni E, Loichinger E, Vogt T. The advantages of demographic change after the wave: fewer and older, but healthier, greener, and more productive? PLoS ONE. Public Library of Science; 2014;9(9):e108501.
Correspondence to: Professor Alistair Woodward, School of Population Health, University of Auckland, New Zealand; email: [email protected]
This is the last contribution from Alistair Woodward as an ANZJPH editor, as he is leaving us after more than five years in the role. We thank him for his sterling contributions to the journal, in particular, for his expertise in the fields of environmental health, population public health, biostatistics and epidemiology. We wish him all the best for the future and look forward to his future academic contributions to the journal.
Australian and New Zealand Journal of Public Health © 2015 Public Health Association of Australia
2015 vol. 39 no. 1
doi: 10.1111/1753-6405.12357
Could we all live to 100? Should we? Alistair Woodward, School of Population Health, University of Auckland, New Zealand
Tony Blakely Department of Public Health, University of Otago Wellington, New Zealand
T
he beginning of the year is traditionally the time for reflecting on how things have gone in the past, and making resolutions about what lies ahead. Here we review one measure of public health success, life expectancy, and look ahead to what may, and should, be achieved in the future. When the first issue of Community Health Studies, the forerunner of this journal, was published in 1977, average life expectancy at birth was 73.4 years in Australia and 72.6 years in New Zealand. The most recent figures, for 2012, are 82.6 and 82.1 years, respectively: in other words, during this journal’s existence average life expectancy in our countries has increased every year by about three months, rather faster in fact for men.
We are seeing a remarkable and underappreciated transformation in human prospects. When Captain Cook landed in New Zealand in 1769, life expectancy in England was in the low 30s; for Māori we estimate the figure was in the high 20s.1 World-wide, average life expectancy has more than doubled in about five generations.2 In the long history of our species, such a change is unprecedented. Death rates have fallen so far that the difference between human hunter-gatherers and the lowest-mortality modern populations is greater, according to one estimate, than the difference in survival between hunter-gatherers and wild chimpanzees.3 The predominant causes of mortality decline vary depending on the time period and the location. In New Zealand, the trajectories have been different for Māori and non-Māori, and what has benefited the latter has to some extent been at the cost of the former. The early, world-leading good health of the European section of the New Zealand population, for instance, was due in large part to the rapid transfer of land and other natural resources from Māori to non-Māori in the second half of the 19th century. Other factors
2015 vol. 39 no. 1
that may have contributed to the rise in life expectancy for non-Māori up to 1940 include: health selection of migrants; lack of crowding and urban pollution that held back mortality improvements in Europe; egalitarian social policies (so that non-Māori at least benefited maximally from opportunities for social development); early initiatives to extend education and promote the position of women; and the economic opportunities that New Zealand enjoyed when it acted as grocer to the British Empire.1 For Māori, we estimate that life expectancy at birth fell to a low point of 20 years or less close to the end of the 1800s, and then rebounded so fast that the gap between Māori and non-Māori was almost halved by 1940. The major forces behind the decline and recovery of indigenous health were poverty and cultural loss, reflected in high fatality from tuberculosis and other infectious diseases, followed by social and, probably, biological adaptation to the new colonial-era disease regime, and this recovery was amplified by political organisation, public health interventions and all-round improvements in living conditions. The major players in the New Zealand mortality stakes in the second half of the 20th century were effective medical treatments (which accelerated the long-term reduction in infectious disease, and more recently slashed mortality from many chronic conditions), the epidemic of cardiovascular disease that stalled life expectancy improvement amongst men for almost 20 years, the tobacco blight that took hold most tenaciously on Māori women, and socially regressive economic policies in the 1980s and 1990s that for a time stretched health inequalities. The story of human life expectancy in Australia differs from the New Zealand experience in some respects. Migration patterns have been different, for example. This brought, we speculate, less advantage
to Australia in the 19th century when the healthy migrant effect acted less forcefully than it did in New Zealand, and greater benefits in the 20th century (when dietary preferences imported from southern Europe contributed to Australia’s speedier recovery from the epidemic of heart disease). However, the similarities are more important than the differences. We note the impact of colonial settlement on Aboriginal health, the mid-20th century transition from infectious to chronic diseases, the predominance of period effects on mortality trends, and improvements in the last 20 years that elevated both countries into the top band of longevity, internationally.4 Where will this lead? A simple linear extrapolation of recent trends implies that average life expectancy in Australia and New Zealand will exceed 100 years before 2100. Will this really happen? Our view is it is unlikely, but not impossible, that we will get to a century by 2100. Unlikely, because it becomes more and more difficult to squeeze out extra years of life expectancy as mortality shrinks.5 Also there is little room in high life span countries for further improvement amongst the young: in the future, substantial gains in life expectancy will depend on relentless reductions in mortality in the oldest age groups. According to one estimate, to reach an average life expectancy of 100 in Australia it would be necessary to reduce the mortality rates that applied in the early 1990s by more than 90%.6 It seems intuitive that there are physical limits to how long the human machinery can keep running. But many commentators have claimed in the past that the improvement in life expectancy is about to hit the ceiling, and they have been proven wrong – life expectancy has kept rising.7 Also, there is no sign we are presently close to biological or social limits on mortality decline, and for these reasons it would be unwise, in our view, to rule out a life expectancy of 100 or more at some time in the future. The longest-lived population in the world, Japanese women, steadily continues its yearon-year improvement in life expectancy.8 Death rates in the oldest age groups continue to tumble, in many countries. Amongst men, New Zealand and Australia are ranked 1 and 2 in the world in terms of average annual increase in life expectancy at age 60 since 1980.9 There are substantial, avoidable causes of mortality in New Zealand and Australia that
Australian and New Zealand Journal of Public Health © 2015 Public Health Association of Australia
3
Editorials
can and should be overcome. To that extent future life expectancy gains, or at least the possibility of future gains, are ‘baked in’. The New Zealand government has committed to reducing smoking prevalence to less than 5% by 2025: if this was achieved life expectancy for Māori would be lifted by about 5 years, and non-Māori by three years, compared to what would apply if the smoking rates in 2006 continued unabated. In our assessment, the gains that can and should be made from the reduction of smoking will exceed the negative impacts of rising body weight.1 Also, both New Zealand and Australia are held back by inequalities in mortality by ethnicity and social status. We estimate that if New Zealand could flatten its socio-economic gradient to the extent that mortality rates of the most deprived quintile of the population were only 15 per cent higher than those in the least deprived quintile, then life expectancy at birth would be boosted by 2-3 years. Note also that recent improvements are not due entirely to the ‘compression of mortality’ (i.e. postponing deaths till some fixed upper limit on life expectancy, which would imply rapidly diminishing gains in the future). There is another force at play – the extension of maximum longevity, which stretches the survival curve to the right, and indicates that further large improvements may still occur. An analysis of European data found that longevity extension was responsible for about 60% of the increase in life expectancy between 1922 and 2006.10 It is unlikely in the foreseeable future that everyone will receive a congratulatory tweet from the Monarch, but the number of people living past 100 years will increase significantly. Remember the standard period life expectancy figures (such as those we cited earlier) assume no future reductions in age-specific mortality. If recent mortality trends continue, Statistics New Zealand estimates that a male born in 2011 will live on average 90.2 years (90% CI 86.3-94.0) and a female 92.9 years (89.3-96.2).11 If this happens, it is likely the median age at death will be creeping up into the mid 90s, and the number of centenarians will multiply. Is this a future we should desire, and strive for? Quality of life is the red flag that everyone raises: it may not be a good thing to live longer if the extra years are spent in poor health. So far, the rise in life expectancy has generally been associated with improvements in the all-round health and functioning of older people, but trends
4
are not clear-cut, not least because of the difficulties in defining, measuring and monitoring good health. In New Zealand, it is estimated that about two-thirds of the years of extra life that have been gained since 1996 have been years without disability, but the time spent living with disability has increased since survival has advanced more quickly than morbidity has retreated.12 From some countries there are reports of an expansion in poor health; at issue is whether states of ill-health are consistently measured and reported over time.13 Looking ahead, it is not certain whether future cohorts of the very old will be more or less resilient than present-day survivor populations. On the one hand, quality of life is clearly not fixed by age and exceptional longevity does not necessarily bring with it excessive levels of disability.14 But the combination of older individuals and older populations will almost certainly deepen the morbidity pool and, as a consequence, raise the demand for health and social services. Whether a world in which we all live to 100 is affordable depends on the scope, cost and effectiveness of health and social services. It depends also on how we view ageing, define productivity, and conceive of ‘affordability’. There are risks. Radical ageing might block opportunities for the young, and lead to social stasis in a conservative, elder-dominated society. On the other hand, better health might enable more people to stay in the workforce longer and, formal employment aside, to be socially productive in many other ways, as volunteers for example. Demographic change may have other advantages: better-educated and longer-lived populations may be more environmentally parsimonious, for example.15 The decline in mortality is a crude and partial indicator of progress in population health, but it cannot be overlooked. Huge changes have occurred; further improvements will be made. Whether life expectancy will reach 100 is not clear, although it would be every cricketer’s model of a ‘good innings’. The present direction in New Zealand and Australia suggests this particular milestone is not out of reach. One can always make a case that other social goals should trump greater longevity. But that has not led, in the past, to serious dis-investment in life-prolonging interventions, and we don’t forsee any change: the collective urge to live longer and look around the next corner is too strong. We anticipate instead difficult and contested
trade-offs, between age groups, generations, and desired outcomes. In this respect, 2015 and the years that follow will resemble closely those that have preceded.
References 1. Woodward A, Blakely T. The Healthy Country? A History of Life and Death in New Zealand. Auckland: Auckland University Press; 2014. 2. Riley J. Estimates of Regional and Global Life Expectancy, 1800–2001. Popul Dev Rev. 2005 Sep 17;31:537–43. 3. Burger O, Baudisch A, Vaupel JW. Human mortality improvement in evolutionary context. Proceedings of the National Academy of Sciences. 2012 Oct 30;109(44):18210–4. 4. Taylor R, Lewis M, Powles J. The Australian mortality decline: all-cause mortality 1788–1990. Aust NZ J Publ Heal. 1998;22(1):27–36. 5. Olshansky SJ. Can a lot more people live to one hundred and what if they did? Accident Anal Prev; 2013 Dec 1;61:141–5. 6. Mathers C, Douglas B. Measuring progress in population health and wellbeing. In: Eckersley R, editor. Measuring Progress. Is Life Getting Better? Melbourne: Collingwood; 1998: 125-156. 7. Oeppen J, Vaupel J. Broken limits to life expectancy. Science. 2002;296(5570):1029–31. 8. Ikeda N, Saito E, Kondo N, Inoue M, Ikeda S, Satoh T, et al. What has made the population of Japan healthy? Lancet; 2011 Sep 17;378(9796):1094–105. 9. Mathers CD, Stevens GA, Boerma T, White RA, Tobias MI. Causes of international increases in older age life expectancy. Lancet. Published Online November 6, 2014. http://dx.doi.org/10.1016/ S0140-6736(14) 60569-9 10. Rossi IA, Rousson V, Paccaud F. The contribution of rectangularization to the secular increase of life expectancy: an empirical study. Int J Epidemiol. 2012 Dec 21;42(1):250–8. 11. Woods C, Dunstan K. Forecasting mortality in New Zealand. Wellington: Statistics New Zealand; 2014. 12. Ministry of Health and Statistics New Zealand. Longer life, better health? Trends in health expectancy in New Zealand 1996–2006. Wellington: Statistics New Zealand; 2009 13. Robine J-M, Saito Y, Jagger C. The relationship between longevity and healthy life expectancy. Quality in Ageing and Older Adults. 2009 Jun 14;10(2):5–14. 14. Christensen K, McGue M, Petersen I, Jeune B. Exceptional longevity does not result in excessive levels of disability. Proceedings of the National Academy of Sciences. 2008;105:13274-9. 15. Kluge F, Zagheni E, Loichinger E, Vogt T. The advantages of demographic change after the wave: fewer and older, but healthier, greener, and more productive? PLoS ONE. Public Library of Science; 2014;9(9):e108501.
Correspondence to: Professor Alistair Woodward, School of Population Health, University of Auckland, New Zealand; email: [email protected]
This is the last contribution from Alistair Woodward as an ANZJPH editor, as he is leaving us after more than five years in the role. We thank him for his sterling contributions to the journal, in particular, for his expertise in the fields of environmental health, population public health, biostatistics and epidemiology. We wish him all the best for the future and look forward to his future academic contributions to the journal.
Australian and New Zealand Journal of Public Health © 2015 Public Health Association of Australia
2015 vol. 39 no. 1
