Guest Blog: Amelia Chong – The demographic timebomb: delayed, not defused

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Earlier this year, the Lords Committee on Public Service and Demographic Change warned that the Government was “woefully underprepared” for the challenges presented by an ageing society [1]. Yet in the BMJ last month, Spijker and MacInnes argued that the population is actually getting younger [2].

No one denies that demographic change is taking place, just look at the stats: in 1901 life expectancy was 45 years for men and 49 years for women, but by 2012 this had increased to 79.2 years and 83.3 years respectively [3].

The disagreement comes when measuring the proportion of older people relative to those who pay for them. Most commonly, this is described by the old age dependency ratio, which takes the number of people who have reached state pension age and divides it by the number of working age (16-64) adults. Today, the figure lies at approximately 31%, but by 2060 it could be as high as 47% [4]. “Without urgent action,” the Lords Committee explains, “this great boon could turn into a series of miserable crises.”

Spijker and MacInnes paint a very different picture though, being heavily critical of the methods used to calculate the old age dependency ratio. The problem is two-fold: everyone aged 65 or over is not dependent and everyone aged 16-64 is not working.

They say, “In a period of lengthening lifespans, not only does the average age of the population increase, so too does the remaining life expectancy associated with each age.” Let’s take a 65 year old woman:  in 1900 she had a life expectancy of 11 years, but today she could expect to live another 21 years. With most acute medical care costs occurring in the final few months of life, this makes her “younger, healthier, and fitter” than her peers in previous generations. 

It is also wrong to assume that all 16-64 year olds work. Younger people stay in education for longer and when they leave, the global economic downturn makes it harder for them to find a job. At the same time, many older workers choose or are obliged to retire early. Even those that are employed may be struggling financially on part-time or zero-hours contracts.

The authors therefore propose a new, more accurate measure, called the real age dependency ratio. This takes the number of people with a life expectancy of 15 years or less and divides it by the number of people in employment, no matter their age. In stark contrast to the old age dependency ratio, this shows that dependency has fallen by one-third over the past four decades and will continue to do so until 2020.

However, caution is needed: it is well-known that recently born generations are less healthy than older ones. As Gerben Hulsegge, from the National Institute for Public Health and the Environment, explains [5]:

“the prevalence of obesity in our youngest generation of men and women at the mean age of 40 is similar to that of our oldest generation at the mean age of 55. This means that the younger generation is ’15 years ahead’ of the older generation and will be exposed to obesity for a longer time.”

This puts them at greater risk of conditions including coronary heart disease, stroke, type 2 diabetes and osteoarthritis.

If the demographic timebomb is to be defused, rather than delayed, there must be greater investment in primary prevention, such as diet and physical activity, and more emphasis on increasing healthy life expectancy: over the last 20 years, life expectancy has risen by 4.6%, but healthy life by only 3% [6]. Otherwise, when today’s generation reaches 65, they will be unable to work and reliant on incapacity benefits. Who will pay for them then?

Amelia Chong

[1] Select Committee on Public Service and Demographic Change. Ready for Ageing? House of Lords, 2013.

[2] Spijker J & MacInnes J. Population ageing: the timebomb that isn’t? BMJ. [Online] 2013; 347: f6598.  Available from: doi: 10.1136/bmj.f6598 [Accessed 1st December 2013].

[3] The King’s Fund. Life expectancy. [Online] Available from:  [Accessed 1st December 2013].

[4] Silcock D & Sinclair D. The cost of our ageing society. ILC-UK, 2012.

[5] European Society of Cardiology. The adult generations of today are less healthy than their counterparts of previous generations. [Online] Available from: [Accessed 1st December 2013].

[6] BBC News. The importance of ‘healthy life expectancy. [Online] Available from: [Accessed 1st December 2013].

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