Everything we know about the way in which people fall apart with age is based on what happened in the past. The research community has access to centuries of good epidemiological data to demonstrate what to expect in old age both with and without modern medicine. Though when you stop to think about the old today, bear in mind that the oldest old spent most of their old age in a time prior to genetic testing, highly effective heart therapies, and many other developments of the past twenty years. Those who are merely elderly still lived half their lives in a medical environment that would appear extremely primitive to anyone forced to cope with it today. We don't tend to think of the period from the 1940s to the 1960s as a backwards era of low-tech medicine, as little separates us culturally from those years, but the widely available medicine of the time was indeed lacking in comparison to today's technology.
Life expectancy is an odd and often misunderstood measure. It doesn't predict future life spans, but rather is a statistical measure of the average life span of a given birth year cohort if they relived the same life history as did the present population of old people. That means the same technologies, the same economic circumstances, the same pace of progress, and so forth. Obviously that won't happen: life expectancy is a useful statistical measure for comparing progress in medicine from year to year, and it does keep on going up, but it isn't a useful tool to inform you of how long you will live. That timeline remains to be determined, and we live in a time of very rapid improvement in biotechnology.
At the best of times there is a decade of lag between laboratory demonstrations and widespread availability in the clinic, and the present state of regulation is far from the best of times. There is a growing disconnect between the accelerating progress of cellular biotechnology and the ever heavier ball and chain shackled to clinical implementation of that research. The gap is widening now, but I think that in the future medical tourism and competition between regulatory regions will overcome this issue: there will be a sudden flood of pent up technology over a fairly short period of time, but who knows when the dam will finally break. The costs of medical development are falling to ever smaller fractions of the present cost of regulatory compliance: if development to the point of practical and reasonably safe usability costs $50 million while compliance costs $500 million, and that isn't too far from the actual state of affairs, then something has to give.
The modern upward trend in adult life expectancy has spanned centuries, created first by control over sanitation and infectious disease, and later by increasingly effective treatments for age-related conditions. We should not expect this to continue as it has been, however. This decade and the opening years of the next are an important transitional period, a shift between (a) the past age in which no attempt was made to treat the causes of aging as a medical condition and (b) the new era in which researchers are focused on aging itself rather than merely patching over its consequences. We should expect a great difference in the trendline of human longevity in the decades ahead precisely because there is a great difference between trying to treat aging and not trying to treat aging.
Thus this paper is not a roadmap for the future of those in their 30s and 40s today. Rather it is a look back at the results of the past for those who are old today:
Disability, functionality, and morbidity are often used to describe the health of the elderly. Although particularly important when planning health and social services, knowledge about their distribution and aggregation at different ages is limited. The older population consists of an extremely heterogeneous group of persons; the older the age group, the greater the variation found in cognition, physical and sensory function, and social engagement, to mention just a few examples.
We aim to characterize the variation of health status in 3080 adults 60+ living in Sweden between 2001 and 2004 and participating at the SNAC-K population-based cohort study using five indicators of health separately and in combination: number of chronic diseases, gait speed, Mini Mental State Examination (MMSE), disability in instrumental-activities of daily living (I-ADL), and in personal-ADL (P-ADL). Probability of multimorbidity and probability of slow gait speed were already above 60% and 20% among sexagenarians. Median MMSE and median I-ADL showed good performance range until age 84; median P-ADL was close to zero up to age 90. 30% of sexagenarians and 11% of septuagenarians had no morbidity and no impairment, 92% and 80% of them had no disability. 28% of octogenarians had multimorbidity but only 27% had some I-ADL disability. Among nonagenarians, 13% had severe disability and impaired functioning while 12% had multimorbidity and slow gait speed.
In this large cohort, we were able to capture the complexity and heterogeneity of health status in 60+ old adults. Until 80, most people do not have functional impairment or disability, despite the presence of morbidity or even multimorbidity. Disability is common only after age 90. The 80s are a transitional period when major health changes take place; often following the co-occurrence of more than one negative health event. If we consider good health as the absence of chronic diseases, functional impairment, and disability, good health is still the most prevalent pattern among sexagenarians. However, even among octogenarians, the most prevalent health state is characterized by presence of chronic disorders with impairment only in gait speed. In other words, morbidity and multimorbidity start early in late adulthood, but functional dependence becomes common only for people older than age 90.