A Special Report by Amy Gutman, Boston-based writer, and Madeline Drexler, editor, Harvard Public Health
The Gray Wave. The Silver Tsunami. The Agequake.
Aging societies have been on the horizon for decades, not just in the United States but also around the world. The driving forces are well-established: falling fertility rates (by far, the most important factor), longer life expectancy, and the maturing of large cohorts such as the baby boomers in the U.S.
But what demographers once thought would be the passage of a single large generation—like the postwar boomers—through the age brackets is now predicted to be a permanent fixture of many developed societies. Age distributions in many countries once formed a pyramid—with billions of young people filling out the bottom and dwindling numbers of older survivors at the apex. Soon, however, this distribution may more nearly resemble a square, with roughly equal numbers of people in each age group.
Imagining what this “new normal” will mean for developed and developing societies alike raises profound questions. How will societies age successfully? Will most people live longer lives but be sicker for more years than in prior generations?
How should work be organized when a society has more people over 65 than under 5? As people live longer, when will they want or need to retire because of cognitive or physical aging? Will growing economies slow or even reverse their trajectories as older cohorts leave the workforce?
What can people do to increase the number of years of healthy, joyful senior living? Will people in their 80s, 90s, or older need as much help with aspects of daily living in the future as they did 20 years ago, or will they be more self-sufficient longer? Will “dying with dignity” be possible in a culture driven by technologically advanced health systems and nursing homes focused more on protecting the frail elderly than on empowering them?
This issue of Harvard Public Health examines how individuals and societies will navigate the previously uncharted waters of rapidly aging societies. Among the experts interviewed are faculty from the Harvard T. H. Chan School of Public Health, in fields ranging from social epidemiology to health policy to biochemistry. Here are their thoughts on what lies ahead.
1. What Is “Successful Aging”?
The MacArthur Foundation Research Network on an Aging Society has defined successful aging by three criteria: avoidance of disease and disability; maintenance of high cognitive and physical function; and engagement with life.
By these standards, the U.S. has generally done well. As life expectancy has improved overall (though some sections of the country have seen declines), more older people have managed to stay healthy or disability-free. This scenario—higher life expectancy and lower incidence of disease and disability—has led to what public health researchers call a “compression of morbidity”: more years spent in good health and fewer lived in poor health.
In the future, will people enjoy a “compression of morbidity”—living both longer lives and fewer years in poor health? Or will those extra years be spent paying the price of unhealthy lifestyles—in poor health due to heart disease, diabetes, and other chronic conditions?
But according to Lisa Berkman, Thomas D. Cabot Professor of Public Policy and of Epidemiology at the Harvard T.H. Chan School of Public Health and director of the Harvard Center for Population and Development Studies, this promising trend may have stalled in recent years. “There is evidence from national studies that people who are now in their 30s and 40s may actually be in worse shape than people that age were a generation ago—an increase in diabetes, obesity, and other chronic conditions,” she says.
“This virtuous cycle, where people are living not only longer but healthier, may not continue.” Moreover, says Berkman, there are substantial social and economic gaps in healthy life expectancy, with those who are poorer or who have less education facing much worse outcomes. And racial and ethnic disparities in healthy aging reflect a historical legacy of disadvantage.
WILL AGING SLOW THE ECONOMY?
An older population with chronic diseases bodes ill not only for public health but also for the economy. “Nations with swiftly aging populations may find themselves with a growing disease burden on their hands: nearly one-quarter of the world’s burden of disease is attributable to illness in adults aged sixty and over,” notes an article in the Spring 2015 issue of Daedalus written by David Bloom, Clarence James Gamble Professor of Economics and Demography in the Harvard ChanDepartment of Global Health and Population; David Canning, Richard Saltonstall Professor of Population Sciences and professor of economics and international health; and research assistant Alyssa Lubet. “In turn, the majority (nearly 70 percent) of the older-adult disease burden is due to noncommunicable diseases (NCDs) such as heart disease, cancer, chronic respiratory disease, musculoskeletal conditions, and mental disorders such as Alzheimer’s and dementia.”
As a result, population aging may slow economic growth, strain existing pension and health care systems, and weigh down younger generations. “One dire prediction,” the authors warn, “is that population aging will slow or perhaps even reverse the engines of national economic growth.”
ORGANIZING WORK REQUIRES NEW ASSUMPTIONS
“Until now, everybody had been looking at what makes individuals age successfully. But nobody asked: How do societies age successfully?” observes Berkman. “What happens to a country when there are more people over 65 than there are under 5? The fundamental issues are not how are we going to pay for Social Security or Medicare, although those are not trivial issues. The deeper issues are how should work be organized? What will happen to people with disabilities? How do different life trajectories lead to different health outcomes? In dealing with these issues, you can’t reorganize a little bit—you have to reorganize dramatically. To do this well, you have to rethink a lot of assumptions as a society.”
DOES AGE NO LONGER MATTER?
One of the fundamental assumptions that may change is that all older people need help. In economics, the oft-cited Old Age Dependency Ratio—or ratio of individuals ages 65 and older (presumably “dependent”) to those ages 18–65 (in the labor force)—bears this out. But in 2014, Dana Goldman of the University of Southern California and colleagues published in the Journal of Gerontology a study of older Americans that contradicts this model. The researchers found that among individuals ages 85 and older, 28 percent had excellent or very good self-reported health and 56 percent reported no health-based limitations in work or housework. As the study’s authors ask, “When does age no longer matter?”
2. Sowing Healthy Habits
Don’t smoke. Exercise regularly. Eat a healthy diet filled with plenty of fruits and vegetables, replace saturated fats with plant oils, and limit sugar-sweetened beverages. Drink moderate amounts of alcohol.
Those are the pillars of healthy aging, according to Walter Willett, Fredrick John Stare Professor of Epidemiology and Nutrition and chair of the Department of Nutrition at the Harvard Chan School. And a mountain of public health research backs up his advice—including the Nurses’ Health Study (NHS), established in 1976 by the Harvard Chan School’s Frank Speizer, now professor of environmental science, with funding from the National Institutes of Health.
This ongoing investigation, which began with some 121,000 middle-aged women, “shows the flip side of the coin,” explains Willett—revealing not only the conditions that elevate the risk for disease but also those that help prevent potentially fatal conditions, from breast cancer and atherosclerosis to diabetes and dementia.
The Nurses’ Health Study defines healthy aging as survival past age 70 without any major chronic diseases or major impairments in memory, mental health, or physical abilities. In 2011, all of the women in the original NHS were 65 or older. Here are the study’s key findings about their healthy aging:
BODY MASS INDEX (BMI)
Of the women who survived until at least age 70, those who had a higher BMI at midlife were less likely to survive to a healthy old age. Obese women (with BMI of 30 or greater) had an 80 percent lower chance of healthy survival compared with their leaner counterparts (with BMI between 18.5 and 22.9). And the more weight a woman gained from age 18 until midlife, the lower her chance for healthy survival after age 70.
Higher physical activity levels at midlife predicted healthier survival. Better yet, the chance of healthy aging markedly improved even at modest activity levels: Women who jogged or cycled about five hours per week almost doubled their chance of healthy aging. Two or more hours per week of brisk walking also upped the chances of a healthy old age. Perhaps most encouraging: Regardless of whether a woman was lean or over-weight, being physically active increased her odds of optimal health.
MEDITERRANEAN DIET AND TELOMERES
The Mediterranean diet appeared to increase telomere length, a key biomarker of aging. Likened to the plastic tips on the ends of shoelaces, telomeres are stretches of DNA at the ends of chromosomes that protect genetic data. Shorter telomeres are associated with decreased life expectancy and increased rates of age-related chronic diseases.
FLAVONOIDS AT MIDLIFE
A midlife diet rich in flavonoids improved the odds of healthy aging. Bioactive compounds in plant foods, flavonoids have been linked to lower risks of fatal or nonfatal cardiovascular disease, hypertension, stroke, cancer, diabetes, and neurodegenerative diseases. High-flavonoid foods include oranges, berries, onions, and apples.
VITAMIN D AND COGNITION
Among women ages 60 to 70, lower levels of vitamin D in the blood of were associated with significantly worse cognitive function—such as memorization of words and numbers. The finding bolsters the theory that vitamin D, which is critically important for bone and muscle health and the prevention of falls, may also play a role in brain function.
3. Rethinking Work
When Social Security was established in 1935, most other government benefits kicked in at age 65. To put that in context, life expectancy for American men at the time was only about 60 years. Today, however, according to the Social Security Administration, men who retire at age 65 can expect to live for an additional 19 years; women, an additional 21 years. Should retirement therefore be postponed?
In general, being employed is positively associated with health, says Lisa Berkman. Partly that’s because healthy people are more likely to be able to work. But employment itself also appears to bring both physical and mental health benefits. Having a job boosts social engagement, keeps up intellectual and interpersonal skills, and staves off the time when one must draw on savings and pensions. “One of the good parts of working longer is the maintenance of cognitive functioning,” says Berkman. “In societies where retirement age is early, such as France and Italy, cognition falls more as people age.”
That fact argues for delayed retirement. But not everyone is able or willing to stay in the workforce, in part because people hold onto their health or lose it at vastly different rates—and government policies must acknowledge this heterogeneity. According to Berkman, certain segments of the population—such as people whose health has been worn down by physically arduous jobs—need the option to take an early path to retirement. And as David Bloom notes, people who are more educated and who earn more tend to live longer—which raises questions of fairness in retirement policies. “If some people will have much longer lives and some people will have just modestly longer lives, but you raise the retirement age for everybody, there’s an ethical issue,” he said in a recent interview.
BENEFITS OF VOLUNTEERING
Perhaps the most convincing argument for encouraging people to keep busy and engaged after 65—whether or not in the formal workforce—is a raft of research showing that senior volunteering has been tied to reduced risk of hypertension, improved self-reported health and well-being, delayed physical disability, enhanced cognition, and lower risk of death. And research shows that while members of lower socioeconomic groups are less likely to volunteer, they will reap disproportionately greater benefits.
“One of the good things about eternally volunteering is that it embeds people in social networks,” explains Berkman. “They are engaged, they work with others, they collaborate with people of all ages. They’re not receiving support, they’re giving support—and giving support turns out to be really important. One of the best things we can do is to keep people naturally embedded in communities that are cohesive and enduring.”
Employment can yield both physical and mental health benefits as one ages – a potent argument for raising the retirement age. But for those whose jobs have worn them down physically or emotionally, the discussion about raising the retirement age raises important ethical and practical issues.
In the U.S., the most robustly studied volunteer program is Experience Corps, which invites volunteers ages 55 and older into public elementary schools several times a week (for at least 12 hours total) to tutor children at risk of reading failure. A 2010 study in Social Science & Medicine by S.I. Hong of the National University of Singapore and Nancy Morrow-Howell of Washington University compared changes in health outcomes over two years between Experience Corps volunteers and a matched sample of older adults who were not engaged in high-commitment volunteering. The study found that the Experience Corps group reported fewer depressive symptoms and fewer functional constraints in such activities as walking, running, or climbing stairs, while the comparison group showed an increase in these measures.
REMOVING THE COBWEBS
A 2009 study in the Journal of Gerontology by Michelle Carlson of the Mailman School of Public Health at Columbia University and colleagues explored in finer detail the cognitive gains among Experience Corps volunteers. This small study involved African-American women in Baltimore. All were all low-income and low-education and therefore faced a statistically greater risk for cognitive impairment. The researchers used fMRI scans, which measure blood flow, to trace the biological underpinnings of brain plasticity. After their stints as volunteers, the women demonstrated increases in activity in several key areas of the brain, compared with those in the control group. They also had better scores in standard tests of visual function and concentration. As one woman said of her time at Experience Corps, “It removed the cobwebs from my brain.”
“[T]hese activities are generative in giving meaning and purpose to one’s life … which may make them more rewarding and personally enriching than highly stimulating activities performed alone,” the researchers wrote. “As a result, individuals may place more value on these activities beyond their immediate personal benefit and may sustain interest longer.”
Just as compelling, the program’s dividends were truly multigenerational, reaching far beyond the volunteers themselves. Compared with students in the control schools, the kindergarten-to-third-grade students in the Experience Corps schools had improved standardized reading scores and markedly fewer referrals for behavioral problems.
4. Breakthroughs in Biology
Imagine old age without heart disease, cancer, or dementia. Imagine a long life of physical and mental vigor, capped by a brief period of decline before death. Imagine being able to achieve this ideal through a pill or simple changes in diet.
That’s exactly what Harvard Chan School scientists in the Department of Molecular Metabolism are imagining in their quest to understand the biology of senescence and the secrets of what has come to be known as “healthy aging.”
JUNKING THE “RUST” METAPHOR
Until recently, bodily decline was considered to be the inevitable outcome of tiny corrosive hits to the system: genetic, cellular, metabolic, environmental, stress-induced. The reigning metaphor was the body as rusting car, with each failing part the final stage of a distinct chain of biological events.
Today, however, researchers suspect there is a fundamental cause behind all these seemingly separate breakdowns. “As humans grow older, they don’t get just one aging-related disorder—they suffer a spectrum of disorders,” says associate professor James “Jay” Mitchell. “The new thinking is that these disorders are mechanistically linked to the aging process itself—whatever that process is.”
According to assistant professor William Mair, the key questions in this new paradigm are: “Why are we more likely to get diseases when we’re old than when we’re young? And how can we shift that risk of frailty?”
CLUES IN THE LAB
The idea that aging is driven by a biological mainspring is buttressed by epidemiological studies of centenarians. These resilient human survivors of 100-plus years tend to die
not from cardiovascular disease or malignancies or neurodegeneration, but rather from the complications of overall deterioration and the body’s inability to maintain homeostasis and rebound from injury or infection. Centenarians usually succumb swiftly at the end—to a broken hip, say, or a short bout of pneumonia. Put another way, they enjoy a longer “health span.”
Can centenarians’ hardy biology be replicated? Mitchell and Mair believe it can.
Animal research has proven that dietary restriction—whether cutting total calories, reducing specific dietary constituents such as proteins, or placing animals on various fasting regimens—extends life span and decreases age-related debility. So dramatic is this biological benefit, Mitchell describes its inverse—today’s human epidemic of obesity-related metabolic disorders—as a wave of “premature aging.”
Elaborating on these findings, Mitchell has shown that lowering quantities of certain amino acids in the diet causes mice to increase cellular production of the gas hydrogen sulfide, which in turn protects the animals against tissue damage after minor surgery. He has also found that increased production of the gas extends life span in worms, flies, and yeast—along the same biological pathways conserved in Homo sapiens.
Research in the lab suggests that dietary restriction—cutting calories or reducing certain items in the diet—extends lifespan and decreases age-related debility. In that context, today’s human epidemic of obesity-related diseases could be seen as a wave of “premature aging.”
Mair, meanwhile, has demonstrated that nematode worms that express an active form of a protein called AMPK—a kind of molecular fuel gauge—were likewise long-lived, despite eating normally. The implication is that tweaking cellular mechanisms in the nervous system that sense energy generated by nutrients could confer the same propensity for healthy aging as do low-calorie diets, without the need to alter food intake.
Both Mitchell and Mair foresee a day when their kind of basic research finds its way into human clinical medicine.
Mitchell predicts that doctors may someday prescribe certain kinds of fasts before surgery or chemotherapy to boost the body’s resilience and improve outcomes. Mair hopes to find molecular targets that could pave the way to therapeutic drugs; if taken in old age—when one was about to encounter risk factors for certain diseases or suffer early symptoms—the medications could prevent the afflictions or at least reduce their spread or severity.
The goal, the scientists agree, is not a fountain of youth but rather golden years that are relatively robust and independent. As Mitchell sees it, “Aging is a public health problem—and basic biology is the answer.”
5. Connecting With Others
Good advice on lifestyle and successful aging is one thing— following it is another. “Many investments have to be made throughout the life course, in terms of health habits like exercise and diet,” says Ichiro Kawachi, John L. Loeb and Frances Lehman Loeb Professor of Social Epidemiology and chair of the Department of Social and Behavioral Sciences at the Harvard Chan School. “But I’m also interested in what you can do once you do reach old age and you haven’t made those investments. Can you still make a difference?”
Kawachi’s answer: a resounding “yes.”
“One of the most important things that you can do individually, if you retire, is to maintain social connections,” he says. “Connecting with other people is as important as diet and exercise. It’s not too late, even at age 60, to overcome some of the health problems you may have encountered earlier in life.
“When you socialize and converse with friends, you’re exercising all your facilities and improving blood flow to the brain, which helps maintain cognitive function,” says Kawachi. “There’s exchange of information of different kinds, such as learning about the latest health tips or getting advice. And you receive affirmative messages and emotional support.”
Socializing with friends after retirement is as important as diet and exercise. It improves blood flow to the brain, maintains cognitive function, promotes the exchange of useful information, and elicits emotional support.
SURPRISES FROM JAPAN’S “SPORTS CLUBS”
Japan’s population is aging at the fastest pace of anywhere in the world. The proportion of its population over the age of 60 is projected to rise to an astounding 42 percent by 2050. To minimize the impact of this trend on health care costs, Japan’s government has focused on preventing long-term care as much as possible—using social participation approaches.
One of Kawachi’s intriguing studies, published in PLOS One in 2012, looked at the effect of membership in Japan’s “sports clubs”— organizations that offer mini-golf, walking clubs, lawn tennis, croquet, and other activities shared with friends. He divided his subjects, who were 65 and older, into four groups: those who were physically active and belonged to a sports club; those who were physically active but exercised alone; those who were not physically active but still belonged to a sports club (doing administrative or other work); and those who were not physically active and did not belong to a sports club.
As predicted, people who actively exercised and belonged to sports clubs enjoyed the best health. But those who belonged to sports clubs and didn’t exercise came in a very close second—their functional disability rate was virtually the same as the avid sports club exercisers. Those who exercised alone actually fared worse than the sports club sedentarians. And the stay-at-home couch potatoes, not surprisingly, came in last.
“In other words, the exercise didn’t add to the benefits of participating,” says Kawachi. “It was the belonging that prevented disability.”
IKIGAI: A LIFE WORTH LIVING
In a 12-year study of more than 30,000 men and women published in 2009 in the Journal of Psychosomatic Research, a Japanese team of researchers explored the effect of Japan’s powerful—but, to Westerners, perhaps ineffable—concept of ikigai, which the Japanese believe to be an important factor for achieving health and a fulfilling life. Ikigai is variously defined as something to live for, the joy and goal of living, a life worth living, or “the reason to get out of bed.” It includes not only pleasure and happiness but also meaning and self-realization. As a baseline measure at the beginning of the study, the researchers simply asked participants: “Do you have ikigai in your life?”
In Japan, people who said they had ikigai—pleasure and happiness, a life of meaning—12 years later had lower risk of death from all causes.
A dozen years later, the middle- aged and elderly men and women who answered “yes” had less risk of death from all causes, including external causes such as injury. Death from stroke and coronary heart disease was also lower among men and women with ikigai than among those without it.
6. Preserving Purpose
In 1991, a family practice physician named Bill Thomas conducted a radical experiment: He brought life to a place where death had prevailed.
A PARAKEET OR A PLANT
The medical director of Chase Memorial Nursing Home in the upstate New York town of New Berlin, Thomas was struck by the sterility and despair that pervaded every room. So he issued an almost unfathomable order: to move 106 additional residents into the facility, pretty much all in one day. The newcomers included two dogs, four cats, and 100 parakeets. They were soon followed by a colony of rabbits, a flock of laying hens, and hundreds of indoor plants. Each of the nursing home’s human residents was soon taking care of his or her own parakeet or plant.
ABOLISHING NURSING HOME PLAGUES
Thomas calls himself a “nursing home abolitionist.” He sees his mission as eradicating what he calls the three plagues in modern nursing homes: boredom, loneliness, and helplessness. And he is one of Atul Gawande’s heroes. In his new book Being Mortal: Medicine and What Matters in the End, Gawande, a surgeon, professor in the Department of Health Policy and Management at the Harvard Chan School, and director of Ariadne Labs, explores the “medicalization of mortality”: the myopic focus on disease instead of goals when caring for patients at the end of life.
“When we don’t know what people’s priorities are, their care is often out of alignment with some of their most important goals,” Gawande said in a recent interview. “You really see it when you visit people who end up requiring residential care—assisted living or full-scale nursing homes. The facilities look more and more like hospitals. They’re built around nursing stations. The rules are focused on safety.”
By the end of life, fewer than one-third of people have conversations about their goals and priorities for the time they have left. But having these conversations often eases suffering, reduces unwanted care, and sometimes even extends life.
On the one hand, it seems prudent to put safety first in nursing homes. But the upshot is that other goals of life may matter more to people, Gawande says. “People are forbidden from having a drink if they want to. Alzheimer’s patients on medically ordered puréed diets get caught sneaking cookies. You could have a roommate imposed upon you with no choice whatsoever. No regard for privacy. These are incredibly important concerns.”
Gawande’s prescription for this devastating mismatch of intent and results includes a list of clarifying questions that should be asked when a person has a serious or life-threatening illness, such as cancer, congestive heart failure, chronic obstructive pulmonary disease, or end-stage renal disease.
CONVERSATIONS IMPROVE OUTCOMES
“We measure the wrong things,” he says. “Less than a third of the time do people who arrive at the end of life have any conversation about what their goals and priorities are for the time they have left. When they have those conversations, they have markedly better outcomes, including reduced suffering, spending more time at home, and also living at least as long as they otherwise would—in many cases, longer. And better outcomes means that they’re less likely to get unwanted care. They have more peacefulness at the end of their lives.”
AUTONOMY, NOT JUST SAFETY
Gawande adds that Bill Thomas’ innovative experiment and similar interventions have demonstrated that people with the opportunity for purpose—even caring for a bird—at the end of life can bring meaning and joy to one’s final days, even for people with severe disabilities.
But to get there, society must overturn its conventional thinking about old age. “There are sometimes regulations that stand in the way, but most of the obstacles are cultural,” Gawande says. Medical care professionals frequently focus on giving patients the longest possible life, regardless of the quality. What a patient with a terminal disease may actually be looking for is “a few good days,” Gawande notes. As one nursing home administrator told him, “Safety is what we want for those we love; autonomy is what we want for ourselves.”
Illustrations by Shaw Nielsen