Not so long ago it was a surprise that people were living so long.  Now we constantly hear “we are all living longer”. But recent mortality data in the UK surprised in the opposite direction: more people have died than expected.  It’s complicated, but it looks like a slowing down rather than a reversing of the trend towards longer lives. We are still likely to keep living longer. Policy makers and anyone planning retirement need to keep anticipating longevity improvements.

What’s happened? The Continuous Mortality Investigation (CMI) has published “Recent mortality in England & Wales“:

After more than a decade of fairly steady mortality improvement, the last few years have had low and sometimes negative mortality improvements. Mortality in 2015 to date has been particularly heavy.

What does that mean? Mortality improvement is the currency of those actuaries and demographers who measure life expectancy. Mortality improvement is a good thing as it means the probability of death among people of a certain age is lower than it was last year.

If there has been mortality improvement across many ages, then overall life expectancy for that population will have improved. A trend of mortality improvement tells us we are living longer: each generation has longer average lifespans than the previous one.

The CMI research tells us that, in England & Wales, this trend looks very different after 2011 than before, and especially different in 2015.  Specifically, after a period of gradual mortality improvements, there has been almost no improvement after 2011.  The all-ages mortality improvement was 2.4 per cent every year from 2000 to 2011, but just 0.3 per cent a year from 2011 to July 2015.  Added to that, there has been unusually high mortality in 2015 to July.

Why has it happened? The unusually high number of deaths in 2015 can be partly explained by seasonal fluctuations – there are more deaths in cold winters, especially of older people. In the winter of 2014/15 the deaths happened to fall in the early part of 2015. In January 2015 there were 33 per cent more deaths than in January 2014.

Even allowing for 2015 being unusual, there is still the slowing of mortality improvements since 2011 to explain. However, in mortality analysis, five years is a short period of time from which to judge longer-term trends. There appears to be no obvious reason for the 2011 change.

So what? Without any causal explanation, it’s not possible to say whether mortality improvements will continue at a slower rate, or pick up again.  The mortality improvement of 2.4 per cent a year from 2000 to 2011 was exceptionally high; the longer-term trend over four decades prior has been more like 1.6 per cent a year (for the whole of the UK)*.  So the slowdown in the last five years could be a correction towards a steadier rate of improvement.

It seems highly unlikely that the recent data is a sign that mortality improvements will stop or reverse, which would mean younger generations would live shorter lives than their parents.  There are no explanations for why this would be the case that stack up against the contrary arguments including that obesity and diabetes make us ill and may shorten life for some people but there are still more population health improvements to come from smoking cessation and potentially yet more from diet and activity improvement. Medical technology continues to come up with new ways of keeping us alive.

The best argument for a continuation of gradual mortality improvement over the long term is the relentless trend of past improvement in both period and cohort life expectancy across the world, as demonstrated by Oeppen and Vaupel (2002) and Shkolnikov et al. (2011).  The few instances of sustained worsening of mortality have been a result of massive upheaval such as the significant HIV/AIDS epidemic in parts of Africa or the change in social order in post-Soviet states (see, for example, Wilson 2011).

The UK’s Office for National Statistics (ONS) still believes the mortality of the UK population will continue to improve, assuming that the long-run rate of future mortality improvement will be 1.2 per cent a year for most ages.

Implications for policy makers and retirement planners? Keep a close eye on mortality trend data, but still plan on average lifespans getting longer.

 

*See Table 4.4 in O’Connell, Alison. (2012). “Underestimating lifespans? Why longevity risk exists in retirement planning and superannuation policy.” PhD thesis.  Victoria University of Wellington. http://researcharchive.vuw.ac.nz/bitstream/handle/10063/2135/thesis.pdf?sequence=2.

Oeppen, Jim and James W Vaupel. (2002). “Broken Limits to Life Expectancy.” Science 296(10 May 2002):1029-1031.

Shkolnikov, Vladimir M., Dmitri A. Jdanov, Evgeny M. Andreev and James W. Vaupel. (2011). “Steep Increase in Best-Practice Cohort Life Expectancy.” Population and Development Review 37(3):419-434.  DOI: 10.1111/j.1728-4457.2011.00428.x

Wilson, Chris. (2011). “Understanding Global Demographic Convergence since 1950.” Population and Development Review 37(2):375-388. DOI: 10.1111/j.1728-4457.2011.00415.x