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Why have improvements in mortality slowed down?

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Until recently, mortality rates in England and Wales had been falling steadily. However, since 2011, the rate of improvement has slowed and trends in mortality have become more erratic (Figure 1). Strikingly, a sharp rise in mortality in 2015 meant that life expectancy at birth actually fell, before it recovered in 2016. What is causing these changes in the long-term trend?

A line graph showing Age standardised mortality rates 2001-2016 England and Wales

Two factors are uncontested. The first is the slowing of mortality improvements is principally the result of changes in mortality among older people. Put simply, more older people – particularly older women – than expected given historical trends are dying. The second is that flu contributed to excess deaths in some years, notably 2015 and also in 20171 , although the scale of its impact is disputed. Beyond this, views about the underlying factors are hotly contested.

Several researchers cite the impact of austerity, which some claim has resulted in tens of thousands of ‘extra’ deaths.2 3 4 5  Their conclusions are based on statistical analyses examining associations between mortality trends on the one hand, and external factors such as the slowing of NHS spending, cuts in social care budgets, increases in delayed discharges and reductions in benefits on the other.

However, this interpretation has been challenged, mainly on the grounds that association doesn't prove causality,6 7 8  with some arguing that because pensioners have, in fact, been better protected from spending cuts than other groups, austerity cannot be the reason for the change in the long-term trend. Alternative explanations suggested include: a ‘cohort effect’ with gains from, eg reducing smoking, largely already realised; or that older people may be succumbing to more complex and multiple long-term conditions.

Then, there is the influence of statistical artefacts – for example, trends can look different depending on the period over which they are measured9  – and, more fundamentally, the calculation of mortality rates10  is affected by changes in population size and structure and whether these have been suitably adjusted for.

With such a long list of possible explanations, what are we to believe? Understanding the reasons for recent trends in mortality among older people is largely – but not solely – the key to understanding what's happening. But disentangling the effects of the many different factors affecting older people's mortality is immensely challenging. Co-morbidity and frailty makes it difficult to establish cause of death reliably. Changes taking place simultaneously in external factors such as austerity and declining NHS performance – which could itself reflect pressures such as seasonal flu outbreaks – must also be accounted for.

But UK trends are not unique and similar changes are being seen in other European countries. Six of the largest EU countries (France, Germany, Italy, Poland, Spain, UK) saw a fall in life expectancy for both men and women between 2014 and 2015, and female life expectancy at birth fell in 23 of the 28 EU countries, while male life expectancy at birth fell in 16 EU countries.11  The European mortality monitoring network attributed excess mortality in Europe in the winters of 2015, 2016 and 2017 to flu, and the particular strain prevalent (A(H3N2)).12

However, while these fluctuating trends in mortality are not unique to the UK, the slowdown in mortality improvement has been more pronounced here than in other European countries. And this when life expectancy in the UK is already lower than in many comparable European countries.

Attempts at explaining the changes in the long-term trend must address several questions including:

  • why are post-2010 mortality trends (both between and within years) more erratic than in preceding decades?

  • why are similar patterns seen in many European countries?

  • why is the slow-down in mortality improvement in the UK worse than in other European countries?

  • why is it worse in older women than older men?

The debate has become unhelpfully polarised. In our view, single explanations are unlikely to provide the answer; it is more likely that many factors are at play. The gravity of recent trends in mortality warrants a comprehensive and objective review, especially given our poor standing in European life expectancy league tables. The review should be set in the wider European context, which has received inadequate consideration thus far. The starting point should be to ensure that the underlying data is robust; the Office for National Statistics and Public Health England have a key role to play in assessing the possibility of data-related or analytical bias in the figures.

The King’s Fund and the Health Foundation are in discussion with some of the leading figures in this debate. Our aim is get an overview of what is currently known, outline what further work needs to be done, and advise on the steps governmental and statutory agencies should take to keep these trends under review in the longer term.