Demographic perspectives on the rise of longevity

Abstract

This article reviews some key strands of demographic research on past trends in human longevity and explores possible future trends in life expectancy at birth. Demographic data on age-specific mortality are used to estimate life expectancy, and validated data on exceptional life spans are used to study the maximum length of life. In the countries doing best each year, life expectancy started to increase around 1840 at a pace of almost 2.5 y per decade. This trend has continued until the present. Contrary to classical evolutionary theories of senescence and contrary to the predictions of many experts, the frontier of survival is advancing to higher ages. Furthermore, individual life spans are becoming more equal, reducing inequalities, with octogenarians and nonagenarians accounting for most deaths in countries with the highest life expectancy. If the current pace of progress in life expectancy continues, most children born this millennium will celebrate their 100th birthday. Considerable uncertainty, however, clouds forecasts: Life expectancy and maximum life span might increase very little if at all, or longevity might rise much faster than in the past. Substantial progress has been made over the past three decades in deepening understanding of how long humans have lived and how long they might live. The social, economic, health, cultural, and political consequences of further increases in longevity are so significant that the development of more powerful methods of forecasting is a priority.

The long lives of primates and the ‘invariant rate of ageing’ hypothesis

“…These gains have resulted from shifting the majority of deaths from early to later and later ages, with no evidence of slowing the rate at which mortality increases with age (i.e. the ‘rate of ageing’) 2 – 4 . Further substantial extensions of human longevity will depend on whether it is possible to slow the rate of ageing or otherwise reduce late life mortality.…”

Regularities in human mortality after age 105

“…Another question that arises from our results is whether the levelling-off is immutable or flexible. This has key implications for human longevity prospects, because forecasts that propose that life expectancy might increase to more than 100 years hinge on reductions in the risk of death for centenarians and semi-supercentenarians [29]. In the light of our findings, we foresee two contrasting scenarios.…”

Future life expectancy in Europe taking into account the impact of smoking, obesity, and alcohol

“…Mortality projections are essential for forecasting how long people will live on average, for predicting the future extent of population ageing, for determining the sustainability of pension schemes and social security systems, for setting life insurance premiums, and for helping governments plan for the demand for services such as healthcare ( European Commission, 2009 ). Recently, the societal and academic relevance of obtaining reliable and robust mortality forecasts has increased due to the revived debate on the existence and proximity of a limit to human life expectancy ( Fries, 1980 ; Manton et al, 1991 ; Couzin, 2005 ; de Beer et al, 2017 ; Olshansky and Carnes, 2019 ; Vaupel et al, 2021 ); the linkage between life expectancy developments and retirement age in many European countries ( Carone et al, 2016 ; OECD, 2016 ); the stagnation of increases in life expectancy in the United States, the United Kingdom, and other European countries since 2011 ( Murphy et al, 2019 ; Raleigh, 2019 ); and the recent COVID-19 pandemic.…”