On the idea that the human life expectancy is limited to 115 years

The theme of longevity is one that Demography Matters has touched upon in the past. I've written about two interesting case studies, in February 2010 about the Abkhaz of the Caucasus and their mythic longevity, and then in June 2014 about the factors behind the extended life expectancy of the inhabitants of the Greek Aegean island of Icaria. I've also written about broader trends, in December 2014 noting the remarkable global trends which have seen global life expectancy rise substantially. The news, announced earlier this month, that built-in biological failings might limit the human life expectancy to 115 years or so, definitely caught my attention. The study--available here--was outlined by Linda Geddes at Nature.

To investigate, Jan Vijg, a geneticist at Albert Einstein College of Medicine in New York City and his colleagues turned to the Human Mortality Database, which spans 38 countries and is jointly run by US and German demographers. They reasoned that if there’s no upper limit on lifespan, then the biggest increase in survival should be experienced by ever-older age groups as the years pass and medicine improves. Instead, they found that the age with the greatest improvement in survival got steadily higher since the early twentieth century, but then started to plateau at about 99 in 1980. (The age has since increased by a very small amount).

The researchers went on to look at the International Database on Longevity, which focuses on the oldest people and is run by an international team. They found that the maximum reported age of death — the age of the oldest person to die in a given year — in France, Japan, the United States and the United Kingdom (the countries with the largest numbers of supercentenarians) increased rapidly between the 1970s and early 1990s but plateaued in the mid-1990s at 114.9 years. The researchers observed the same trend when they considered the second, third, fourth and fifth oldest person who died in a given year — and a similar peak age of 115 years old when they tracked the maximum annual age of death using another database run by the international Gerontology Research Group, which validates supercentenarian claims.

Vijg’s team concludes that there is a natural limit to human lifespan of about 115 years old. There will still be occasional outliers like Calment, but he calculates that the probability of a person exceeding 125 in any given year is less than 1 in 10,000.

The limit is surprising, says Vijg, given that the world’s population is increasing — supplying an ever-increasing pool of people who could live longer — and that nutrition and general health have improved. “If anything you would have expected more Jeanne Calments in recent years, but there aren’t."

But not everyone agrees with his team's interpretation. The age experiencing the greatest increase in survival may have plateaued in many countries, says James Vaupel, founding director of the Max Planck Institute for Demographic Research in Rostock, Germany. But it has not yet plateaued in some that are particularly relevant to this research, namely Japan, which has the world’s highest life expectancy — 83.7 years for those born in 2015, nor in France or Italy, which have large populations and high life expectancies.

Vijg’s paper includes “one-sided conclusions”, says Vaupel. But Vijg argues that the increase in the survival age in even these three countries has significantly slowed down in recent years and so seems to be trending towards no increase.

This report garnered a lot of attention from the mainstream media, The Guardian, NPR, and The Atlantic providing some insightful commentary. The Atlantic notes the arguments that frailties inherent in the human organism make it unlikely that this ceiling will be raised, not without unforeseen technological advances.

The ceiling is probably hardwired into our biology. As we grow older, we slowly accumulate damage to our DNA and other molecules, which turns the intricate machinery of our cells into a creaky, dysfunctional mess. In most cases, that decline leads to diseases of old age, like cancer, heart disease, or Alzheimer’s. But if people live past their 80s or 90s, their odds of getting such illnesses actually start to fall—perhaps because they have protective genes. Supercentenarians don’t tend to die of major diseases—Jeanne Calment died of natural causes—and many of them are physically independent even at the end of their lives. But they still die, “simply because too many of their bodily functions fail,” says Vijg. “They can no longer continue to live.”

[. . . I]f early development and childhood experiences are so important to our future health, it’s notable that today’s centenarians were born in the 1900s. It might be that longevity records “haven’t yet seen the impact of the improved sanitation, healthcare, vaccinations, and hygiene advances that took place in the 1930s and later,” says Holly Brown-Borg from the University of North Dakota. Or perhaps, “our poor diets and lack of exercise have countered those gains.”

That’s unlikely to matter much, says Vijg. “Once you survive your childhood, you’re really more likely to survive over long periods of time. And there have been enormous advances in keeping older people alive much longer. We’ve continued to make progress in medical care and safety standards, and there are more and more people. You can’t explain the fact that there aren’t older people that Jeanne Clement except to say that we’ve hit a ceiling.”

We have pushed that ceiling upward for laboratory animals, like worms, flies, and rodents. But these creatures were specifically bred by scientists to grow fast and reproduce rapidly. Many of the techniques for extending their lives, from drugs to calorie restriction, probably work by simply slowing their artificially inflated growth.

Similar tricks might increase our healthspan, and raise our average life expectancy. But Vijg believes that the most we can hope for is to be very healthy for around 115 years, after which our bodies will just collapse.

“There’s no question that we have postponed aging,” adds Judith Campisi, from the Buck Institute for Research on Aging. “But to engineer an increase in maximum lifespan, we’ll probably have to modify so many genes that it won’t be possible within our lifespan—or even our grandchildren’s lifespan.”

Even granting the arguments of Campisi and others that--assuming this limit does exist--this limit of 115 years cannot be breached in the foreseeable future, there's still much that can be done. Most obviously, in no country does the average life expectancy actually reach 115 years, or come close to it. Moreover, as noted by many of the people interviewed, there is still much that can be conceivably done to make the human process easier. Biomedical interventions into the aging process and specific diseases aside, I noted in my treatments of the Abkhaz and the Icarians specific things that can be done--inclusive social structures, for instance, and relatively healthy diets--that can do much to extend not only longevity but healthy lifespans. The commentary at Forbes, concentrating on the specific case of Japan, provides stil another example. In a generation's time--perhaps even in my generation--decline and death may end up being postponed and not so nearly drawn out.

The consequences of any scenario involving extended longevity are notably significant. A worst-case scenario might involve an extension of human life expectancy towards supercentenarian territory without a corresponding increase in a person's active and healthy lifespans. The financial costs of supporting these people for additional decades would be extreme, to say nothing of the human cost to specific individuals who might well not relish added years of suffering. The Greek mythological figure of Tithonus, who suffered the tragic consequences of being granted immortality but not eternal youth, comes to mind. Conversely, a scenario where longevity and health are extended could have very positive consequences.

One note on the global revolution in longevity

A recent Bloomberg article, Dani Bloomfield's "It’s the Best Time to Be Born as Life Expectancy Tops 70", caught my eye.

These are good times to be a baby. A child born last year will live six years longer on average than one born in 1990, the first time in history that life expectancy worldwide extends past age 70.

Much of the gain has come from poor countries, where better health infrastructure has helped people live dramatically longer lives, according to a paper published today in the journal Lancet. In rich countries, new drugs and other advances are stretching lifetimes, the study’s authors said.

Eastern sub-Saharan Africans saw a 9.2-year gain in life expectancy between 1990 and 2013, the biggest increase of any region. In some countries, such as Rwanda, Nepal, Niger and Iran, the outlook increased by more than 12 years.

“Outside of Southern Africa there’s been quite substantial improvement in life expectancy everywhere,” said Christopher Murray, the study’s lead author and a professor at the University of Washington, in Seattle. Except for 1993, when the worldwide estimate was hurt by genocide in Rwanda, “you can see that global life expectancy, particularly since 2000, has been going up 0.3 of a year, every single year.”

Worldwide, the expected length of life for an infant born last year grew 6.2 years, to 71.5 years old, according to the study, which was sponsored by the Bill & Melinda Gates Foundation.

The paper in question, "Global, regional, and national age–sex specific all-cause and cause-specific mortality for 240 causes of death, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013", is available in its entirety online.

Global life expectancy for both sexes increased from 65·3 years (UI 65·0–65·6) in 1990, to 71·5 years (UI 71·0–71·9) in 2013, while the number of deaths increased from 47·5 million (UI 46·8–48·2) to 54·9 million (UI 53·6–56·3) over the same interval. Global progress masked variation by age and sex: for children, average absolute differences between countries decreased but relative differences increased. For women aged 25–39 years and older than 75 years and for men aged 20–49 years and 65 years and older, both absolute and relative differences increased. Decomposition of global and regional life expectancy showed the prominent role of reductions in age-standardised death rates for cardiovascular diseases and cancers in high-income regions, and reductions in child deaths from diarrhoea, lower respiratory infections, and neonatal causes in low-income regions. HIV/AIDS reduced life expectancy in southern sub-Saharan Africa. For most communicable causes of death both numbers of deaths and age-standardised death rates fell whereas for most non-communicable causes, demographic shifts have increased numbers of deaths but decreased age-standardised death rates. Global deaths from injury increased by 10·7%, from 4·3 million deaths in 1990 to 4·8 million in 2013; but age-standardised rates declined over the same period by 21%. For some causes of more than 100 000 deaths per year in 2013, age-standardised death rates increased between 1990 and 2013, including HIV/AIDS, pancreatic cancer, atrial fibrillation and flutter, drug use disorders, diabetes, chronic kidney disease, and sickle-cell anaemias. Diarrhoeal diseases, lower respiratory infections, neonatal causes, and malaria are still in the top five causes of death in children younger than 5 years. The most important pathogens are rotavirus for diarrhoea and pneumococcus for lower respiratory infections. Country-specific probabilities of death over three phases of life were substantially varied between and within regions.

Causes of mortality, the authors suggest, are shifting globally away from communicable diseases towards non-communicable diseases and injuries.

This news item put me in mind of a 2010 post I made about the grim demographics of the Roman Empire, and by extension almost all other pre-modern societies of note. Mortality was by our contemporary standards terrifyingly high, especially high in the early lives of human beings, to an extent that even the least developed societies in our 21st century world would have difficulty comprehending. That world life expectancy is now comparable to that of Canada in the 1960s is a remarkable transformation without precedent, and something quite worth watching.

On the longevity and extended health of Icarians, among others

Via the Washington Post I came across a 2012 article in The New York Times Magazine by Dan Buettner, "The Island Where People Forget to Die". In this article, Buettner highlights the longevity and good health of the inhabitants of Icaria, a small Greek island in the Aegean Sea several dozen kilometres away from the Anatolian mainland where the average inhabitant can expect to live a decade longer than the average American. While many factors seem to contribute to the Icarians' situation--an abundance of exercise, a healthy diet, and so on--it seems that all these individual elements are reinforced by Icarian society as a whole.

In the United States, when it comes to improving health, people tend to focus on exercise and what we put into our mouths — organic foods, omega-3’s, micronutrients. We spend nearly $30 billion a year on vitamins and supplements alone. Yet in Ikaria and the other places like it, diet only partly explained higher life expectancy. Exercise — at least the way we think of it, as willful, dutiful, physical activity — played a small role at best.

Social structure might turn out to be more important. In Sardinia, a cultural attitude that celebrated the elderly kept them engaged in the community and in extended-family homes until they were in their 100s. Studies have linked early retirement among some workers in industrialized economies to reduced life expectancy. In Okinawa, there’s none of this artificial punctuation of life. Instead, the notion of ikigai — “the reason for which you wake up in the morning” — suffuses people’s entire adult lives. It gets centenarians out of bed and out of the easy chair to teach karate, or to guide the village spiritually, or to pass down traditions to children. The Nicoyans in Costa Rica use the term plan de vida to describe a lifelong sense of purpose. As Dr. Robert Butler, the first director of the National Institute on Aging, once told me, being able to define your life meaning adds to your life expectancy.

[. . .]

If you pay careful attention to the way Ikarians have lived their lives, it appears that a dozen subtly powerful, mutually enhancing and pervasive factors are at work. It’s easy to get enough rest if no one else wakes up early and the village goes dead during afternoon naptime. It helps that the cheapest, most accessible foods are also the most healthful — and that your ancestors have spent centuries developing ways to make them taste good. It’s hard to get through the day in Ikaria without walking up 20 hills. You’re not likely to ever feel the existential pain of not belonging or even the simple stress of arriving late. Your community makes sure you’ll always have something to eat, but peer pressure will get you to contribute something too. You’re going to grow a garden, because that’s what your parents did, and that’s what your neighbors are doing. You’re less likely to be a victim of crime because everyone at once is a busybody and feels as if he’s being watched. At day’s end, you’ll share a cup of the seasonal herbal tea with your neighbor because that’s what he’s serving. Several glasses of wine may follow the tea, but you’ll drink them in the company of good friends. On Sunday, you’ll attend church, and you’ll fast before Orthodox feast days. Even if you’re antisocial, you’ll never be entirely alone. Your neighbors will cajole you out of your house for the village festival to eat your portion of goat meat.

Every one of these factors can be tied to longevity. That’s what the $70 billion diet industry and $20 billion health-club industry do in their efforts to persuade us that if we eat the right food or do the right workout, we’ll be healthier, lose weight and live longer. But these strategies rarely work. Not because they’re wrong-minded: it’s a good idea for people to do any of these healthful activities. The problem is, it’s difficult to change individual behaviors when community behaviors stay the same. In the United States, you can’t go to a movie, walk through the airport or buy cough medicine without being routed through a gantlet of candy bars, salty snacks and sugar-sweetened beverages. The processed-food industry spends more than $4 billion a year tempting us to eat. How do you combat that? Discipline is a good thing, but discipline is a muscle that fatigues. Sooner or later, most people cave in to relentless temptation.

This message was emphasized by an 2013 article in The Guardian by Andrew Anthony, based at least in part on the author's interviews with Buettner.

The phrase "blue zone" was first coined by [author Dan] Buettner's colleague, the Belgian demographer Michel Poulain. "He was drawing blue circles on a map in Sardinia and then referring to the area inside the circle as the blue zone," Buettner says. "When we started working together, I extended it to Okinawa, Costa Rica and Ikaria. If you Google it now, it's entered the lexicon as a demographically confirmed geographical area where people live measurably longer." So what does it take to qualify? "It's a variation," Buettner says. "It's either the highest centenarian rate, so the most centenarians per 1,000. Or it has the highest life expectancy at middle age."

All the blue zones are slightly austere environments where life has traditionally required hard work. But they also tend to be very social, and none more so than Ikaria. At the heart of the island's social scene is a series of 24-hour festivals, known as paniyiri, which all age groups attend. They last right through the night and the centrepieces are mass dances in which everyone – teenagers, parents, the elderly, young children – takes part. Kostas Sponsas tells me he no longer has the energy to go on until dawn. He will now usually take his leave by 2am.

One evening, the island's star violin player, whom we met at Gregoris Tsahas's favourite cafe, invites Buettner, me and several others back to his house to hear him play. He says he often grows exhausted while performing at festivals, but the energy and enthusiasm of the people keep him going. He plays some traditional folk tunes, full of passion and yearning and heart-rending beauty, and mentions with pride that Mikis Theodorakis, the composer of Zorba The Greek, was among the leftists exiled on the island in the late 1940s. Theodorakis later recalled the experience with pleasure. "How could this be?" he asked. "The answer is simple: it's the beauty of the island in combination with the warmth of the locals. They risked their lives to be generous to us, something that helped us more than anything bear the burden of the hardship."

One of the things Buettner has found that unites the elderly inhabitants of all the blue zones is that they are unintentionally old: they didn't set out to extend their lives. "Longevity happened to these people," he says. "The centenarians didn't all of a sudden at 40 say, 'I'm going to become 100; I'm going to start getting exercise and eating these ingredients.' It ensues from their surroundings. So my argument is that the environmental components of places such as Ikaria are portable if you pay attention. And the value proposition in the real world is maybe a decade more life expectancy. It's not living to 100. But I think the real benefit is that the same things that yield this healthy longevity also yield happiness."

I ask a number of men in their 90s and 100s if they do any keep-fit exercise. The answer is always the same: "Yes, digging the earth." Nikos Fountoulis, for example, is a 93-year-old who looks 20 years younger. He still has a smallholding in the hills of the island's interior. Each morning he goes out at 8am to feed his animals and tend his garden. He used to dig charcoal as a younger man. "I never thought about getting old," he says. "I feel good. I feel 93, but on Ikaria that's OK."

Long-time readers of Demography Matters may remember that I visited the phenomenon of extended life expectancy and relatively gentle aging before, in a February 2010 post taking a look at the position and numbers of the aged in Abkhazia. Fantastic claims that Abkhazians regularly lived past the century mark have been debunked. Conversely, traditional Abkhazian culture does seem to have not only promoted good health, but helped integrate aging Abkhaz into their society in a way that allowed them to continue to be productive. (I know nothing about the current situation in Abkhazia. Anyone informed on this subject, please advise in the comments.)

Is it possible to learn from the lessons of Icarians and similar populations? Maybe. As commented in the articles I linked to above, Icarians' longevity appears to be the product of a complex mesh of social factors that can't be easily replicated. Whether the relaxed lifestyle of Icarians and others can be replicated in our contemporary world is very open to question, for instance. If nothing else, the Icarian experience does provide fascinating hints towards a possible futuree.

Some demography links

This afternoon--this afternoon in Toronto, at least--I thought I'd share with you five interesting demographics-related blog posts.

At Behind the Numbers, Mark Mather reports on the news that men in the United States are catching up to women in terms of life expectancy.

Dealing with my earlier post about biased sex ratios in the South Caucasus, fellow Livejournaler demographer has written--translated post here, original post here--on the subject, suggesting that the apparent deficit is a consequence of the underregistration of female births.

Geocurrents' Martin Lewis writes about the barrier along the Pakistani border built by the Iranians, dividing the historical region of Baluchistan. While built in an effort to control insurgents, the wall has a secondary use of limiting Pakistani migration into Iran.

The Global Sociology Blog links to an extended BBC series describing the effects of the male-biased sex ratio in India, describing things as varied as the grief of women forced to abort their daughters, the migration of women from more sex-balanced areas in southern India to the male-biased north, the shocking deterioration in the sex ratio in Kashmir, and Indian government efforts to encourage the birth of female children.

At Marginal Revolution, Tyler Cowen summarizes a new book by Youssef Courbage and Emmanuel Todd and the subtitle is A Convergence of Civilizations: The Transformation of Muslim Societies Around the World. This book makes the point, made here several times, that Muslim societies around the world are also going through the demographic transition, albeit each in their own distinctive ways.

Two current cases of sustained life expectancy decline, and one possible future one

Co-blogger Scott Peterson recently linked to a study suggesting that in the United States--and by implication, other high-income countries and/or countries with high rates of obesity--the expected sustained increase in life expectancy might not happen, indeed, might be reversed.

“Over the next few decades, life expectancy for the average American could decline by as much as 5 years unless aggressive efforts are made to slow rising rates of obesity, according to a team of scientists supported in part by the National Institute on Aging (NIA), a component of the National Institutes of Health (NIH)…The U.S. could be facing its first sustained drop in life expectancy in the modern era, the researchers say, but this decline is not inevitable if Americans — particularly younger ones — trim their waistlines or if other improvements outweigh the impact of obesity…

The new analysis, by S. Jay Olshansky, PhD, of the University of Illinois at Chicago, Leonard Hayflick, Ph.D., of the University of California, San Francisco, Robert N. Butler, M.D., of the International Longevity Center in New York, and others* suggests that the methods used to establish life expectancy projections, which have long been based on historic trends, need to be reassessed. This reevaluation is particularly important, they say, as obesity rates surge in today’s children and young adults.

“Forecasting life expectancy by extrapolating from the past is like forecasting the weather on the basis of its history,” Olshansky and his colleagues write. “Looking out the window, we see a threatening storm — obesity —that will, if unchecked, have a negative effect on life expectancy.”

Unlike historic life expectancy forecasts, which rely on past mortality trends, the Olshansky group bases their projection on an analysis of body mass indexes and other factors that could potentially affect the health and well-being of the current generation of children and young adults, some of whom began having weight problems very early in life. The authors say that unless steps are taken to curb excessive weight gain, younger Americans will likely face a greater risk of mortality throughout life than previous generations.”

The idea surprises me, but it shouldn't have. I've heard enough about the metabolic syndrome, strongly associated with obesity along with high blood glucose levels, high blood pressure, and so on, to know that its health consequences can be severe, particularly insofar as diabetes and heart disease is concerned. Three of the four risk factors leading to the metabolic syndrome--not genetics, but yes weight, aging, and a sedentary lifestyle--are becoming increasingly common in our increasingly overfed, aging, and physically inactive world. Can medical technology compensate for this? It's open to question.

Long-standing health issues leading to sustained stagnation or declines in life expectancy reminds me of what happened in the Soviet Union, where--contrary many popular reports--life expectancy decline began as early as the 1960s.

During the 1960s, though, life expectancy in the United States rose rapidly, while life expect-ancy in the Russian republic faltered and began to decline. The gap between East and West in life expectancy, like the gap in economic performance, grew steadily wider.

This trend was already apparent by the early 1980s. In a 1982 Population Bulletin published by PRB, Murray Feshbach, former chief of the U.S. Census Bureau's research unit on the USSR's population, noted "the mortality rise of the last decade and a half" and cautioned that "[I]f the health sector is neglected, the adverse mortality trend which has resulted in a major reduction in the life expectancy of Soviet males may persist."

The story within the story came in the late 1980s, when then-President Mikhail Gorbachev instituted a vigorous antialcohol campaign as part of a wider effort to rescue Russian society, and the Soviet state, from self-destruction. The draconian, unpopular, and probably unsustainable campaign produced a sharp but temporary improvement in mortality rates. The collapse of the public health campaign, the collapse of the Gorbachev government, and the breakup of the Soviet Union nearly coincided in 1988 and 1989. The progress quickly made since the mid-1980s was just as quickly lost, and the long-term decline continued until the mid-1990s.

Cause-of-death data are difficult to use for comparisons over long periods or across countries with very different medical and statistical systems, but several independent analyses have come to the same conclusion: The decline in life expectancy and the gap between levels in Russia and the rest of Europe can be attributed mainly to abnormally high rates of cardiovascular disease and injury, for both of which abuse of alcohol was a major risk factor.

But limiting the comparison to the last 10 or 12 years is misleading. Comparing the unusually good years of 1986 and 1987, when the antialcohol campaign was most effective, with the lowest points of the mid-1990s exaggerates the speed of decline. Any other choice of start and end dates would produce a more characteristic picture of steady, long-term decline.

Sharply rising infant mortality from the early 1970s on certainly didn't help. According to Eberstadt in 1988, with the exception of Georgia and Armenia, life expectancy was significantly below Western levels as a result of lifestyle risks, with life expectancy in developed Russia being on part with underdeveloped Uzbekistan's.

Arguably, the HIV/AIDS epidemic in southern Africa is similar in its determination by long-term trends, with the sustained catastrophic drop in life expectancy even in wealthy South Africa produced by a combination of overlapping sexual networks and an apartheid-era migration system that helped break down community and family structures.

Average life expectancy declined from 62 years in 1990 to 50 years in 2007; it is projected to fall even further by 2011, to 48 years for men and 51 for women, according to the Institute's annual South Africa Survey.

The authors note that among 37 developed and developing countries, South Africa is one of only six where life expectancy fell between 1990 and 2007, with only Zimbabwe showing a steeper decline.

Of South Africa's nine provinces, those with the highest HIV prevalence rates also had the lowest life expectancy - KwaZulu-Natal at 43 years, followed by Free State and Mpumalanga, both at 47 years. The leading causes of death were tuberculosis (TB), influenza and pneumonia, all common opportunistic infections associated with HIV/AIDS.

Seventy percent of people diagnosed with TB in South Africa were co-infected with HIV, and "it is thus reasonable to assume that at least 70 percent of observed mortality from tuberculosis, and by extension a comparable percentage of deaths from influenza/pneumonia, also has HIV and AIDS as an underlying cause." Nearly half of all deaths in 2008 were thought to be HIV/AIDS related - up from a third in 2001.

Gail Eddy, a researcher at the Institute, commented that although neither the public health system nor the government's antiretroviral (ARV) treatment programme were reaching all those in need, particularly in rural areas, a slight decrease in mortality rates in the last two years may be the result of ARVs gradually becoming more widely available.

The HIV/AIDS epidemic contributed to a 43 percent reduction in population growth between 2001 and 2008; a fall in birth rates also played a role.

Thoughts?

Does the dependency ratio mean all that much now?

The old age dependency ratio--the proportion of people over 65 to people of working age (15 to 64 years of age) is the standard metric for measuring a population's aging, and by extension, the degree to which an aging country's economy will have to somehow cope with the rapid growth of pension expenditures, the contraction of the workforce, et cetera. Now, a new study out of Vienna's IIASA makes an argument that with improving health for older people, the dependency ratio doesn't make that much sense.

Those measures are based on fixed chronological ages, and this can generate misleading results,” says Dr. Warren Sanderson, from IIASA and SBU. “When using indicators that assume fixed chronological ages, it’s assumed that there will be no progress in factors such as remaining life expectancies and in disability rates. But many age-specific characteristics have not remained fixed and are not expected to remain constant in the future.”

However, many people over 65 are not in need of the care of others, and, on the contrary, may be caregivers themselves. The authors provide a new dependency measure based on disabilities that reflect the relationship between those who need care and those who are capable of providing care, it is called the adult disability dependency ratio (ADDR). The paper shows that when aging is measured based on the ratio of those who need care to those who can give care, the speed of aging is reduced by four-fifths compared to the conventional old-age dependency ratio.


Dependency ratios. Authors’ calculation. OADR and POADR are based on UN, World Population Prospects: The 2008 revision (WPP). ADDR are based on both UN WPP and European Health Expectancy Monitoring Unit Survey Data (see references in article). The lower age boundary in all denominations is 20.

Co-author Dr.Sergei Scherbov, from IIASA and the VID, states that “if we apply new measures of aging that take into account increasing life-spans and declining disability rates, then many populations are aging slower compared to what is predicted using conventional measures based purely on chronological age.”

The new work looks at “disability-free life expectancies,” which describe how many years of life are spent in good health. It also explores the traditional measure of old age dependency, and another measure that looks specifically at the ratio of disabilities in adults over the age of 20 in a population. Their calculations show that in the United Kingdom, for example, while the old age dependency ratio is increasing, the disability ratio is remaining constant. What that means, according to the authors, is that, “although the British population is getting older, it is also likely to be getting healthier, and these two effects offset one another.”

The new ratio that Sanderson and Scherbov introduce, of the ratio of disabilities in adults over the age of 20 in a population, does seem to make more sense in certain contexts notwithstanding a degree of subjectivity (what will different statistical agencies define as "disabilities"). The press release quotes the authors as suggesting that, if population aging is much less catastrophic a phenomenon that previously presented--this AFP article reports the authors suggest that "[w]hen aging is measured based on a ratio of those who need care to those who can deliver care, the speed of aging is reduced by four-fifths compared to the conventional old-age dependency ratio"--gradualist reforms of pension and retirement aging, potentially more manageable than sharp hikes, could become possible. Certainly if this ratio did become the new metric social and economic systems would urgently need revision to match.

On population aging and Newfoundland's blood supplies

The aging of populations has any number of consequences in any number of countries for any number of reasons. One consequence that I hadn't imagined at all was a falling number of potential blood donors in Newfoundland and Labrador.

Statistics Canada's latest demographic projection singled out Newfoundland and Labrador as the province with the fastest aging population.

As well, under a low-growth scenario, Newfoundland and Labrador is the only province that could see its population decline over the next 25 years.

"As this demographic shift happens, it will have a two-fold effect on our blood supply," said Sharon Bala, a communications official with the Canadian Blood Services in St. John's.

"First, we'll need more blood and then second, there'll be fewer donors available to donate, so that's why it's really important for us to engage younger people to pick up the torch."

In 2009, the median age of blood donors in Newfoundland was 41, meaning that half of the people who gave blood were older than that.

Bala said Canadian Blood Services has launched a new campaign targeting teens. She said organizers want to recruit donors at a younger age and to foster donation habits that will last for years.

In Canada, as in many other countries, blood is frequently in short supply. Part of this is because (circa 2008)a third of committed donors did not showing up, but as one source notes the demographics of blood donors are become less and less favourable.

Currently, despite the fact that almost everyone will need to use donor blood at some point in their life, less than 4% of eligible donors give blood.

By examining the records from the Canadian Blood Services, several patterns were observed. Firstly, the 15-24 age group showed the strongest likelihood to be donors, whilst those of working age (25-54) were the least likely to be donors. The authors predict that due to an ageing population this reliance on the younger generation will be unsustainable.

The study also showed positive ties between level of education and ability to speak English with donation likelihood, whilst immigrants and the wealthy were less likely to donate. The paper shows that those living in a big city were much less likely to donate blood than those living in smaller cities or towns, coining the phrase "the stingy big-city effect". According to Páez, "The fact that those who possessed a higher level of education were more likely to donate lends weight to the assertion that, with 25% of Canadians thinking there are some risks in donating blood, educating the public would help expand the donor database".

This last may be a consequence of fears dating back to the early and mid-1980s, when many people believed that they could become infected with HIV not only by receiving blood products but by donating blood. Older people with more commitments just find it difficult to set aside the time necessary.

Saberton et al's very extensive and highly recommended study suggests that, in Canada the proportion of blood donors as such doesn't very much by region, with (as noted above) fluency in English and residency in small towns playing more of a role. Newfoundland's very badly off in this regard, with underserviced rural areas and a most unfavourable age pyramid, with low completed fertility compounded by mass emigration of the young and working-age population.

What goes for Newfoundland probably also goes for other countries facing similar demographic issues. Where will the blood needed for surgeries come from in the future? Perhaps the blood could be manufactured. (But how?) Perhaps the blood could be imported. (But the memory of the tainted blood scandals common to most of the developed world will surely prevent this.) It's the sort of conundrum that doesn't seem to have been considered, honestly. Maybe it should.

On what the Abkhaz have to teach us about longevity

The Abkhaz, the titular nation of the quasi-state of Abkhazia in northwestern Georgia, contrary to popular mythology, don't actually live to amazingly long ages. First, here's some background about the Abkhaz, as provided in Georgi Derluguian's "Abkhazia: A Broken Paradise".

Linguistically and anthropologically, the native Abkhazes belong to the North Caucasian group of peoples that also comprises the Adyghs (Adygeis, Circassians, Kabardins) and, more distantly, the Vainakhs (Chechens and Ingushes) and most Daghestanis (Abdushelishvili, Arutyunov and Kaloyev, 1994). To a considerable pride of its native speakers, the Abkhaz language is featured in the Guinness Book of World Records as the world's hardest-sounding tongue. Indeed, it boasts more than sixty consonants to (depending on the dialect) just four, or even one, vowels. The verdict of patriotic Georgian scholars renders Abkhaz merely patois, a backward dialect of the Georgian language. Today, however, comparative linguists consider it proven that the languages of the North Caucasian group are entirely unrelated to any other language family in this part of the world, be it Indo-European, Afrasian (Semitic), Turkic or Kartvelian (a small endemic family that consists of Georgian proper, and the Svan, Mingrelian, and Laz languages) (67).

Until the last quarter of the 19th century, the population of Abkhazia – approximately 100,000; the actual number is difficult to estimate due to the complete absence of any state authority and thus a lack of censuses prior to the 1890s – consisted solely of ethnic native Abkhazes and a few other closely related peoples (such as the Ubykhs) who no longer exist. In 1864, the sweeping push of Russian armies towards the Black Sea provoked among the highlanders a panic that led to mass exodus across the sea into the Ottoman lands: the territories of modern Turkey, Syria, Jordan, and even Kosovo (Ascherson, 1995; Lieven, 1998). This panic of apocalyptic proportions swept the entire expanse from Daghestan and Chechnya in the east Caucasus to the Circassian lands and Abkhazia in the western parts. Since Abkhazia was situated right on the Black Sea coast, the emigration was particularly massive there. At least half or perhaps as many as three quarters of Abkhazes abandoned their native land in successive waves following the series of crushed rebellions between 1864 and 1878.

As Zhenglian et al. noted in their paper "Age validation of Han Chinese centenarians", exaggerations of the numbers of extremely old age are common in any number of states and nations.

Many researchers have indicated that elderly people tend to exaggerate their age. Thoms (1873, 2nd ed. 1878) found that the ages of about 90% of the centenarians reported in the newspapers during the period 1868-72 could not be validated. In the literature, age exaggeration by those claiming to be centenarians was often reported (see, for example, Bowerman, 1939). Among the 1756 reported centenarians in a census taken in Bulgaria at the beginning of this century, only 51 could be verified (Vischer 1945). This problem of overstatement of age by the extremely old has been found in the United States (Myers, 1966; Rosenwaike, 1968), and in the former Soviet Union (Medvedev, 1973, Myers, 1965). A carefully-validated census taken in
Vilcabamba found that all the age claims made by those reporting their age to be over 100 years old, were either incorrect or unsubstantiated. Systematic age exaggeration was found from 70 years old onwards (Mazess & Forman, 1979). This is especially true of extremely old people who come from societies where illiteracy is high, accurate documentation showing date of birth does not exist, and even accurate oral information about birth dates is lacking (Mazess and Forman, 1979). A revaluation of actual ages among a sample of Abkhazians showed that the earlier reports of increased longevity in Abkhazia were erroneous. In fact, the study concluded that extreme old age was no more prevalent in Abkhazia than in the U.S.A. (Palmore, 1984). Age exaggeration was, in fact, very common around 1900 in most of Europe. It is still common today in most other countries of the world, especially in countries with a high proportion of illiteracy (Jeune, 1995, p. 17).

The methodology of the Soviet studies (Other cultures, elder years, Ellen Rhoads Holmes and Lowell Don Holmes) was flawed, with statistics fluctuating wildly from census to census and a near-complete lack of documentation to back up claims. In actual fact, they suggest, only 0.3% of Abkhazians in 1970 may have been older than 90 years, a proportion above the Soviet average and comparable to the American. The acceptance of the myth of Abkhaz longevity might not be surprising, since iIn the book Forever Young: A Cultural History of Longevity by Lucian Boia and Trista Selous, the point is made (155-160) that long lifespans were seen as legitmizing factors for the Soviet system.

Stalinism had set up a complete mythology that overlaid every aspect of real history and ordinary life. Although cracked and losing credibility, this fictiious discourse on the world, supported by the transformist project inherent in Stalinism, survived the Red dictator's death. It's ebb was slow and affected the core ideology only very partially.

Longevity followed. the same pattern. The Caucasians became thinner on the ground, but did not disappear altogether. The year 1974 saw celebrations for the 140th birthday of a lady in that region, who died the following year. [. . .] She was 85 when she joined a collective farm; at 104 she travelled to Moscow for the USSR's first agricultural exhibition; at 128 she was still working. Her speed and skill made her a model for the other workers.

Another source observes that Stalin, just like China's emperor Qin Shi Huangti, wanted to live for a long time and hoped that evidence from his native Caucasus could legitmize his hopes.

Anthropologist Sula Benet's classic 1974 ethnography The Abkhasians: The Long-Living People of the Caucasus is arguably one of the best sources on the Abkhaz. The 1954 census, she noted, claimed 2.58% of Abkhasia's population over 90, versus 0.1% in USSR, a figure verified according to the following method.

First, documentary evidence as sought to substantial their statements to demographers; second, a lengthy questionnaire was administered by local physicians. It included such questions as age when married, age when first child was born, age when the siege of Sevastopol occurred, and age when the Tuyrks invaded his village. 'If a respondent really knew his age, his answers would give a consistent pictures. If he did not know his true age, major discrepancies would apear. Unless the respondents (often an illiterate or semi-literate peasant) were extremely agile with numbers, any deliberate attempt to mislead the interviewer would also show up here.

This method, it should be noted, didn't allow (as noted above) for unintentional misunderstandings.

Still, as observed in the Globe and Mail some time ago, elderly Abkhaz do seem at least anecdotally to enjoy relatively happy lifespans.

Jinjolia's bent frame can be seen pacing the grounds of his sprawling three-hectare garden, occasionally leaning on his walking stick for support. His son and grandson are buried under a canopy farther up the mountain and Mr. Jinjolia still climbs the slope to sit at their graves.

His face is wizened now and his voice is a high-pitched whine, but Mr. Jinjolia's brown, darting eyes are clear. It's also clear that he rules the roost in the family home. At a late-afternoon lunch earlier, his family and neighbours stood in respect while he toasted guests.

They didn't touch their glasses until Mr. Jinjolia finished speaking from the head of the table.

Why has he lived so long? "I don't know," he shrugged. "All my life I've drunk and smoked and chased girls," he said, laughing.

But most of his life was just hard. He said he doesn't remember much about the Bolshevik Revolution, but he does remember the hard years that followed, when he was put to work at age 12 on a collective farm. "I was too young to go to work," he said.

When the Second World War erupted, Mr. Jinjolia was sent to the Russian front twice and was shot on both tours of duty. His two convalescences were the only periods in his life when he was hospitalized.

Once, in 1930, he says, he contracted malaria, but he drank some vodka and recovered. His first marriage ended in divorce, his second wife died and his third wife passed away 20 years ago.

He wanted to marry one more time, but was afraid he would outlive her too.

Ms. Ashuba's long life was also marked by the great social upheavals of the 20th century. She too picked tobacco for decades on a collective farm. After her husband was killed in the war, Ms. Ashuba raised six children on her own. Her salary from the collective farm was paid in food, not money.

"Each year, I prepared one tonne and 300 kilograms of tobacco and each month a I got a few pieces of soap, corn and sugar," she said.

Ms. Ashuba said her life improved after the Soviet Union's collapse even though the breakup brought more war and unrest to the Caucuses.

"Life here in Abkhazia is better," she said, during an interview beneath a cherry tree on her family's gated compound. "When I was young, I had to work all the time. I would work until I collapsed."

As she spoke, her 76-year-old son Ilia and 68-year-old daughter, Eteri, hovered nearby, periodically bringing coffee, cheese and vodka.

A neighbour, Natella Shlarba, said Abkhazians feel a moral duty to care for their elders. "We don't have [seniors' homes]. If you don't take care of your parents, no one will say hello to you on the street. All this love that is given to people makes them live longer."

Benet claimed that aging begins later among Abkhazians, with many working to an advanced age on light tasks, with a large minority having good vision and hearing, perhaps controversially claiming that Abkhaz had no phrase for "old people" (9-10). can this be justified?

Chapter 2 of her ethnography suggests it may be. Benet argues that Abkhaz are traditionally concerned with their weight as a health issue, with a traditional diet marked by moderate protein and little consumption of fat or carbohydrates, with wine, fruits and vegetables, honey, fermented milk, and fresh meat dominating. She further argues that age is the major determinant of social status instead of wealth or social tradition, with the elderly playing a central role in the preservation of Abkhaz culture and a strongly patriarchal and extended family structure encouraging close family ties and the elderly's continued participation in family life. The role played by age in social structure apparently didn't produce conflict between age groups since each age group inherited the privileges of the older ones in turn, all within a context of a culture with established mechanisms for resolving conflict (63). To the extent that genes play a role, Benet speculates that the relative isolation of the Abkhaz for millennia and established traditions of adoption, ritual and otherwise, may have helped consolidate a homogeneous gene pool. Benet's conclusion is unsurprising.

Abkhasians live as long as they do primarily because of the cultural, social and psychological factors that structure their existence. The most important are: the uniformity and predictability of both individual and group behaviour; the unbroken continuum of life's activities; and integration of the aged into the extended family and community life as fully functioning members in work, decision making, and recreation. No less important are thye culturally reinforced expectation of long life and good health; cultural mechanisms used in avoidance of stress and lack of intergenerational conflict. All these factors are most conducive to longevity (103).

Curiously, in a parallel she notes that longevity is paired with a relativly low birthrate, high rate of adoption, and flat age profile by the standards of surrounding population. For instance, a 19633 surbvey of Atara-Abkhaskaya revealed that some "60% of all peasant households had either one or two children, while 8.1% had no children at all. Two percent of the households had adopted one or two children, and only 12 percent had more than five children" (66).

Benet's analysis of the Abkhaz situation seems to hold up. Caloric restriction and diet do play a major role in sustaining health and extending lifespans; social structures which include the elderly at the same time they regulate derived social conflicts play important psychological roles; family structures which help create fairly broad and extended group solidarity help. The extent to which this has survived in an Abkhazia devastated by war and economic collapse is open to question, true, but I don't think it's too much to claim that despite the propaganda surrounding claims of special Abkhaz longevity there's still a fair bit that aging societies can learn about the ways in which the Abkhaz traditionally dealt with their health and with their elderly.