Predicting future life expectancy is of exceptional interests to pension providers, health insurance providers, and life insurance providers. These companies use life expectancy to calculate the premiums that consumers have to pay. One constant throughout history has been that these companies underestimated future life expectancy with severe financial repercussions (Blake, 2008). But also individuals are underestimating their own life expectancy and consequently often fail to adequately plan their old day finances (Society of Actuaries, 2012).
Most studies use a single model to predict life expectancy. The new study however builds a more robust approach by creating an ensemble of 21 models (Kontis et al., 2017). Each model gives a slightly different prediction. Hence the authors obtained for each gender within each country a range of possible future life expectancies with the most likely life expectancy being in the middle of this range. The authors selected 35 industrialized countries with a population of over 1 million and for which good demographic data are available between 1985 and 2010. The analysis covered countries in European, North-America, Latin America, Asia and the Pacific.
The model predicted that there’s a 65% chance that lifespan will increase in all 35 countries for women and a 85% chance for men. There was a 57% chance that life expectancy at birth for south-Korean women will exceed 90 years by 2030. The biggest gains for life expectancy are likely to be found in South-Korea, Slovenia, and Portugal for women and in Hungary, South-Korea, and Slovenia for men. Surprisingly, South-Korea which already has one of the largest life expectancies of the world is project to have one of the largest gains of these 35 countries another country with a large life expectancy today, Japan, is predicted to have one of the smallest future gains. For women Japanese gains in life expectancy is the 3rd lowest for women and the 7th lowest for men of all 35 countries. Despite this small gain Japan remains one of the countries with the largest life expectancy at birth.
The largest life expectancies at birth in 2030 are predicted to be found in South-Korea, France, and Japan for women and in South-Korea, Australia, and Switzerland for men. The average prediction for life expectancy at birth in 2030 ranged between 73 (Serbia) and 84 (South-Korea) years of age. As said above, for each country there was a range of possible life expectancies. The upper limit in 2030 for women is 98.70 years (South-Korea) and for men 89.88 years (Slovenia). The lower limit in 2030 for women is 75.99 (Serbia) and 67.88 (Bulgaria) for men.
Studies like this one are based on projecting future gains in life expectancy on historical increases in life expectancy. Up until now the decrease in early life mortality has driven the increase in life expectancy but with early life mortality becoming negligibly small the projections in future life expectancy increases show only small gains. While the authors indeed predict that the future gains in life expectancy will be driven mostly by gains in life expectancy above the age of 65 this is still based on projecting life expectancy increases from historic data. Improvements in life expectancy above age 65 has so far been driven by improvements in the treatment of specific diseases of old age. However, treatments for specific diseases of old age have little effect on life expectancy. For example, a complete cure for heart disease would add less than 3 years to life expectancy. In contrast treatments that reduce the rate of aging have large effects on life expectancy. In contrast, if the human rate of aging was slowed to the same extend as calorie restriction does in mice studies then human life expectancy would increase by more than 30 years (Martin et al., 2003). Even at current life expectancy people born in 2030 can be expected to live to the 22nd century and it seems very unlikely that aging would not be cured by then. Keeping all other causes of death (e.g. car accidents and homicide) constant life expectancy in a non-aging population will exceed 1,200 years (Rose, 2000). The authors acknowledge this in the discussion section where they write “The key limitation of our work, shared by all projections of the future, is the inability to account for completely unexpected events and changes in the social, technological, and health systems determinants of health”.
In 2003 sixty prominent gerontologists were asked what the life expectancy would be of someone born in 2100. Estimates ranged from as little as 75 (at the time life expectancy in Hong Kong was already 83) to as much as 5,000 years with an average estimation of 292 years (Richel, 2003).
Blake D (2008). It is all back to front: critical issues in the design of defined contribution pension plans. In: Broeders D, Eijffinger S, Houben A (eds.). Frontiers in pension finance. Edward Elgar, Cheltenham (UK).
Kontis V et al. (2017). Future life expectancy in 35 industrialised countries: projections with a Bayesian model ensemble. Lancet [Epub ahead of print].
Miller RA (2002). Extending life: scientific prospects and political obstacles. Milbank Quarterly 80: 155-174.
Richel T (2003). Will Human Life Expectancy Quadruple in the Next Hundred Years? Sixty Gerontologists Say Public Debate on Life Extension Is Necessary. J Anti-Aging Med 6(4): 309-314.
Rose MR (2000). Aging as a target for genetic engineering. In: Stock G, Campbell J (eds.). Engineering the Human Germline: An Exploration of the Science and Ethics of Altering the Genes We Pass to Our Children. Oxford University Press, New York (USA).
Society of Actuaries (2012). Key findings and issues: Longevity. 2011 risks and process of retirement survey report. Available online: https://www.soa.org/files/research/projects/research-key-finding-longevity.pdf