The continued increases in life expectancy with no obvious deceleration, the proliferation of centenarians and appearance of supercentarians (those aged 110 years and over) leave us in no doubt that the belief that life expectancy was limited to 85 years is now untenable. Although we may ask how long the limits to life can be pushed, the crucial question is whether the extra years gained year on year in life expectancy are healthy years. This paper begins by reviewing what was historically believed to be the theoretical relationships between life expectancy and healthy life expectancy. We debate how current knowledge of mortality rates in the old and oldest old, the trends in healthy life expectancy, and the gap between the genders shed light upon these theoretical models, discussing the fact that different models may exist in different cohorts of the same population. The paper closes with some speculations on how we might monitor the evolution of healthy life expectancy more closely, particularly in those countries still early on in the ageing transition. Background The debate about the relationship between life expectancy and healthy life expectancy and the move from simply considering the length of life to the quality of remaining life began over two decades ago, though the debate at that time was predominantly theoretical with little data to prove or disprove theories. As mortality rates at older ages were observed to be falling, three main theories emerged. Gruenberg (1977) predicted a pandemic of chronic diseases, or expansion of morbidity, through the progress in medical care extending the life of those with disease and disability as well as life expectancy increasing to the ages at which disease and disability are more likely. Fries (1980) on the other hand gave a more optimistic outlook, that through behaviour change and prevention, we could postpone the onset of disease and disability closer to the end of life: the compression of morbidity scenario. Central to this argument was the existence of the limit to life expectancy, then thought to be around 85 years. Manton (1982) proposed an intermediate view between these extremes of a dynamic equilibrium, where the prevalence of disability may increase as mortality falls, but the severity of disability is reduced. The dynamic equilibrium scenario points much more clearly to the crucial question of whether the extra years of life are good quality years or not and for the need to introduce a notion of severity. Disability is, at the same time, an indicator of the severity of morbid states and an indicator of the quality of years lived. The introduction of disability into models of health significantly clarified the relationships between disease and mortality leading to the partitioning of years of life into those with and without disability and to the development of health expectancy as a population health indicator to elucidate the three scenarios. This can be seen from Figure 1 (WHO, 2004) which distinguishes three elements: total survival, disability-free survival and survival without disabling chronic disease, leading to life expectancy (LE: area under the ‘mortality’ curve), disability-free life expectancy (DFLE: area under the ‘disability’ curve) and life expectancy without chronic disease (DisFLE: area under the ‘morbidity’ curve). The difference between LE and DFLE measures life expectancy with a disability, the difference between LE and DisFLE measures life expectancy with at least one chronic disease and the difference between DisFLE and DFLE measures life expectancy with at least one chronic disease but without disability.
Stored only when both papers are in the corpus — 20 citations exist upstream.
Imported from OpenAlex (CC0) — nothing here is generated.