James F Fries and the human ‘one-hoss shay’

The originator of the ‘compression of morbidity’ concept made insightful observations, but his predictions missed the mark

On 7 November 2021, an 83-year-old retired doctor called James F Fries died at a nursing home in Boulder, Colorado. Although his death was attributed to ‘end-stage dementia’, he had been profoundly incapacitated following a stroke in 2017. His death was not widely reported in Europe, but in the US, Dr Fries was honoured with a lengthy obituary in The New York Times.

Fries trained as a rheumatologist and spent all his career on the faculty of the Stanford University School of Medicine. He spent the academic year of 1978-9 on sabbatical at Stanford’s Centre for Advanced Study in the Behavioural Sciences. There, he developed the concept of the ‘compression of morbidity’. In July 1980, the New England Journal of Medicine published his paper ‘Ageing, natural death, and the compression of morbidity’, which, as I write, has had 5,691 citations and has been extraordinarily influential.

Compression of morbidity

Fries’s paper began with two observations, both correct: First, that although average longevity increased dramatically during the 20th Century, maximum lifespan has not; and second, that chronic disease can be prevented or postponed by adoption of a healthier lifestyle. He showed how over the course of the 20th Century, mortality curves had become increasingly ‘rectangular’, with the dramatic reduction in neonatal mortality and premature deaths from infectious diseases. By 1980, chronic illness accounted for more than 80 per cent of deaths in the US. “These chronic diseases,” he wrote, “are approached most effectively with a strategy of ‘postponement’ rather than cure. If the rate of progression is decreased, then the date of passage through the clinical threshold is postponed; if sufficiently postponed, the symptomatic threshold may not be crossed during a lifetime, and the disease is ‘prevented’.” Fries cited the proven benefits in this regard of smoking cessation, treatment of hypertension, weight loss, and regular exercise. Significantly, three of these four are down to the individual taking “personal responsibility for health”.

Fries predicted that widespread adoption of these healthy practices would lead to progressive ‘rectangularisation’, not only of mortality curves, but also of morbidity curves. With this compression of morbidity, the period of illness and disability leading up to death would become progressively shorter. He predicted “that the number of very old persons will not increase, that the average period of diminished physical vigour will decrease, that chronic disease will occupy a smaller proportion of the typical lifespan, and that the need for medical care in later life will decrease”. Fries’s two key observations may have been correct, but all his predictions were wrong. Since 1980, the number of old (and very old) persons has increased; we have seen an expansion of morbidity and the need for medical care at the end-of-life has increased.

Fries’s thesis and worldview chimed with American libertarian ideas of personal freedom and responsibility for one’s own health, wealth, and wellbeing. “Outcome,” he wrote, “is related to choice, assumption of personal responsibility; education for making decisions about personal health and ability to encourage self-care are clearly essential to changing health behaviours.” He did concede, however, returning “responsibility to the patient may cause anguish”.

Review

In 2011, more than three decades after his landmark paper, Fries reviewed the evidence for his hypothesis. This was a rather narrow review, focusing on two long-term cohort studies Fries himself had conducted: The University of Pennsylvania (UPenn) and the Runners studies. The UPenn study followed 2,327 alumni for 21 years; they were stratified for risk by smoking, weight, and exercise. The Runners study followed up 538 members of an over-50s running club and 423 controls, also for 21 years. He concluded that: “Good health habits led to greatly increased functional ability, decreased lifetime disability, and longer lives, with effects on morbidity greater than those upon mortality.” Compression of morbidity may occur in lean, non-smoking joggers, but does it occur in entire populations? The structural biologist Venki Ramakrishnan (Nobel laureate and former President of the Royal Society) wrote in his 2024 book Why We Die: “[D]ata from the Office of National Statistics in the UK… show that the number of years we spend with four or more morbidities has not declined, but actually slightly increased as a fraction of our lives. A United Nations report on the trend worldwide is similar and concludes that both lifespan and disability-free years increased, but the fraction of our lives spent in disability has not decreased. In short, we are living more years and possibly a greater fraction of our lives in poor health.” He added, however, that: “It is conceptually easy to define mortality, but morbidity is much fuzzier. It is defined as a disease, but many chronic illnesses such as diabetes, high blood pressure, or atherosclerosis can be treated with medication and people can lead perfectly normal and satisfactory lives…. Statistics regarding morbidities in old age must be looked at carefully.”

Measures of morbidity include disability-free life expectancy, cognitive impairment-free life expectancy, and dependency (high, medium, low, independent). The UK Cognitive Function and Ageing Study has been running since 1991. In 2017, The Lancet published a comparison (1991 vs 2011) of dependency in old age: They found that on average men spent 2.4 years and women three years with “substantial care needs”; over the 30 years, there was an increase in high dependency of 0.9 years for men and 1.3 years for women. In 2018, the same group concluded that “over the next 20 years there will be an expansion of morbidity, particularly complex multimorbidity (4+ diseases)”.

Social injustice

Why, then, has Fries’s utopia not come to pass? In 2008, the Commission on Social Determinants of Health in England, chaired by the epidemiologist Sir Michael Marmot, concluded that “social injustice is killing on a grand scale”. A striking illustration of this inequity is that life expectancy drops by one year for every two stops you travel eastward from Westminster on the Jubilee London Underground line. A follow-up report by Marmot in 2020 found that “health is getting worse for people living in more deprived districts and regions, health inequalities are increasing and, for the population as a whole, health is declining”.

Meanwhile, a US study found that the richest 1 per cent of American men live 15 years longer than the poorest 1 per cent; for women the difference was 10 years. Even if you control for smoking and obesity, the poor die (and get chronic disease) much younger than the rich. A 2021 study from Oxford found that because of Covid, life expectancy in the UK had dropped by a year, cancelling the gains of the previous decade. The 2020 Marmot report concluded: “In effect this report is calling for a reordering of national priorities. Making wellbeing rather than straightforward economic performance the central goal of policy will create a better society with better health and greater health equity.” Ramakrishnan put it more starkly: “[T]here is a serious risk that we will be creating two permanent classes of humans: Those who enjoy much longer lives in good health and the rest.”

‘One-hoss shay’

Ramakrishnan confesses to finding the concept of compression of morbidity absurd: “If someone was [biologically] ‘young’… what would suddenly cause him or her to collapse and die? It would be like a car that was running perfectly suddenly falling apart.” Economists use the term ‘one-hoss shay’ depreciation to describe assets – classically a lightbulb – that retain value until they suddenly fail. The phrase ‘one-hoss shay’ comes from the Harvard medical Professor Oliver Wendell Holmes’s 1858 poem The Deacon’s Masterpiece, or the Wonderful One-Hoss Shay: A Logical Story. A ‘one-hoss shay’, or one-horse chaise, is a small carriage suitable for a single horse. In the poem (claimed by some to be an allegory of the decline of Calvinism in America), the deacon builds his ‘shay’ with such balance that all the working parts are equally strong – and equally weak. Exactly 100 years after its construction, the ‘one-hoss shay’ suddenly collapses:

. . . it all went to pieces at once –

All at once, and nothing first –

Just as bubbles do when they burst.

Some species of birds experience a ‘one-hoss shay’ deterioration, prompting the veterinary saying, “the bird is fine, the bird is fine, the bird is dead.” Fries, who graduated in philosophy at Stanford before studying medicine at Johns Hopkins, thought the ‘one-hoss shay’ the perfect metaphor for his concept: “These considerations suggest a radically different view of the lifespan and of society, in which life is physically, emotionally, and intellectually vigorous until shortly before its close, when, like the marvellous ‘one-hoss shay’, everything comes apart at once and repair is impossible.” Although a healthy lifestyle does indeed diminish the risk of disabling diseases, the human ‘one-hoss shay’ is a very unusual specimen. The New England Centenarian Study found that even among centenarians, 40 per cent had developed age-related diseases before the age of 80. The rare and wonderful supercentenarians (those over the age of 110), by contrast, remain healthy until their rapid pre-terminal decline. I should add a note of caution here: The Oxford demographer Saul Newman recently argued that many so-called supercentenarians are not as old as they claim, a phenomenon driven by welfare fraud.

Fries certainly practised as he preached; he was an enthusiastic runner, hiker, and climber. He wrote several books on health for general readers, one of which, Take Care of Yourself, sold 20 million copies. His optimistic message, which emphasised individual responsibility, inevitably resonated far more with Americans than Europeans. Fries, despite his healthy habits, did not himself experience a compression of morbidity, enduring more than four years of severe disability. “The compression of morbidity is a compelling idea,” wrote the gerontologists Eileen Crimmins and Hiram Beltrán-Sánchez in 2011. “People aspire to live out their lives in good health and to die a good death without suffering, disease, and loss of function. However, compression of morbidity may be as illusory as immortality.”