Julianne Holt-Lunstad, a professor of psychology at Brigham Young University, Utah, has asked this question: Which lifestyle factors matter the most to our longevity? To establish the answer, she and her colleagues measured the effects of a variety of lifestyle factors in over four million people. The study revealed something remarkable about our biology. The top two factors for reducing the likelihood someone will die early are two features of their social life: strong connections, or close friends, and a factor called social integration—the amount of social interaction one has as one moves through the day: chatting with the neighbor walking by or people at the gym, or belonging to a club, for example. According to the study, having close personal friends and strong social integration are by far the most consistent and powerful predictors for how long someone will live.
Indeed, Holt-Lunstad’s research is clear, perceived loneliness is extraordinarily corrosive to our health—negatively impacting one’s health more than smoking over 15 cigarettes a day. Being lonely translates to a 50 percent greater risk of early death compared to those with a robust social life. By comparison, being obese raises the chance of dying before the age of 70 by around 30 percent. And, Holt-Lunstad’s research shows, moving through life with a rich social network is twice as important as exercise and diet.
Similar studies have shown the astonishingly tight connection between our social lives and our health with equally dramatic results. A 2006 University of California study tracked almost 3,000 women with breast cancer to see if there was a correlation between the richness of their social networks and their survival. The result was dramatic. The study showed that the women with fewer friends were four times as likely to die from the disease compared to women with more robust social connections. Other studies affirmed the association. For example, a study performed by psychologist Martha McClintock at the University of Chicago dramatically illustrated the connection between loneliness and cancer development in rats. McClintock isolated one group of 20 rats by putting each rat in a cage by itself. McClintock divided a second group of 20 rats into four cages, each containing five rats. All 40 rats were genetically prone to mammary cancer. The isolated rats, however, exhibited a 135 percent increase in the number of tumors over the grouped rats, and an 8,391 percent increase in the size of tumors. They exhibited anxious, nervous behavior and ultimately died sooner than the grouped rats. The impact of chronic loneliness on our health measured in terms of longevity is profound: People with more robust networks of friends are likely to live an average of fifteen years longer than lonely people.
But how does loneliness so drastically affect our health? How can something intangible, like social interaction, affect our health more drastically than real, tangible factors such as exercise, diet, air pollution, obesity, or smoking? The answer is a biological loop that knits the neurological inputs generated from interacting with people (perceptions) into a deeply complex cellular response that occurs at the level of the epigenome. The study of this endlessly complex and fascinating looping system has been coined social genomics—an emerging field that centers on how human interaction, or the lack thereof, ultimately affects our health by changing the expression of certain genes.
In the past researchers have tried to understand behavior primarily from the inside out—linking hormones, stress factors, and neurotransmitters to behavioral patterns. Perhaps, says McClintock, this has been the problem all along, “If you look at the journals in my field, 90 percent of the articles look at the effects of physiological, neural, and hormonal systems on behavior, and 10 percent look at the effects of behavior on hormones and the nervous system,” she said. “I don’t think a balance of 90–10 is an accurate reflection of how nature works.” Maybe, as McClintock suggests, researchers have gotten it backward. Maybe the more interesting and dramatic effects on our bodies come from the fuzzy interface of our own perception—face-to-face interactions stimulating the brain to result in effects that cascade through neural networks and penetrate to the level of our DNA through epigenetics.
One of the first studies to show how loneliness penetrates to our core biology came in 2007. The researcher analyzed genes in the white blood cells (immune cells) of healthy older adults who reported different levels of social connectedness. Among the 22,283 genes assayed, 209 showed a different level of expression in the cells of people who reported feeling lonely and distant compared to the cells of those who reported feeling less lonely consistently over the course of four years. When the researchers analyzed the specific genes that were expressed differently, a striking pattern emerged. “These effects did not involve a random smattering of all human genes, but focally impacted three specific groups of genes. Genes supporting the early ‘accelerator’ phase of the immune response—inflammation—were selectively upregulated. However, two groups of genes involved in the subsequent ‘steering’ of immune responses were down-regulated: genes involved in responses to viral infections, and genes involved in the production of antibodies by B lymphocytes.” In other words, the lonely subjects’ immune systems were more prone to deleterious inflammatory responses and less able to mount a targeted response to infection. The authors of the study went on, “These results provided a molecular framework for understanding why socially isolated individuals show heightened vulnerability to inflammation-driven cardiovascular diseases (ie, excessive non-specific immune activity) and impaired responses to viral infections and vaccines (ie, insufficient immune responses to specific pathogens). A major clue about the psychological pathways mediating these effects came from the observation that differential gene expression profiles were most strongly linked to a person’s subjective sense of isolation, rather than their objective number of social contacts.”
That last sentence deserves examining—the “person’s subjective sense of isolation, rather than their objective number of social contacts.” In other words, loneliness isn’t an absolute condition. Rather, it is defined by an individual’s need. As with sleep or caloric requirements, individuals have different social requirements, too. One person might feel well-rested after six hours of sleep, for example, while another person needs nine hours. It is the same with loneliness. Introverts need fewer friends and social interactions throughout the day to feel “not-lonely,” whereas extroverts may require much more interaction.
At the very least, the importance of our social lives to our individual health is vastly underappreciated. “There is robust evidence that social isolation and loneliness significantly increase risk for premature mortality, and the magnitude of the risk exceeds that of many leading health indicators,” wrote Holt-Lunstad. Loneliness is a health crisis. Obesity, especially in America, tends to get stamped as public health enemy number one. But the results of Holt-Lunstad’s research are clear: As a health risk, loneliness eclipses obesity. “Being connected to others socially is widely considered a fundamental human need—crucial to both well-being and survival. Extreme examples show infants in custodial care who lack human contact fail to thrive and often die, and indeed, social isolation or solitary confinement has been used as a form of punishment. Yet an increasing portion of the US population now experiences isolation regularly.”
According to a study conducted by the AARP Foundation, approximately 47.8 million adults over age 45 in the United States are estimated to be suffering from chronic loneliness. The most recent US census data show that more than half of the population is unmarried and more than a quarter of the population now lives alone. And the trend continues. Marriage rates and the number of children per household have continued to decline. “With an increasing aging population, the effect on public health is only anticipated to increase. Indeed, many nations around the world suggest we are facing a ‘loneliness epidemic.’ The challenge we face now is what can be done about it,” said Holt-Lunstad.
There are places, however, where there is no “loneliness epidemic.” Where societies are structured around human interaction. When epidemiologists look at the so-called blue zones, regions where the residents live far longer than average, statistical analysis and observation reveal a consistent pattern of social cohesion. Sardinia, a remote, mountainous Italian island in the Mediterranean, is one such place. Six times as many centenarians live on Sardinia than on the Italian mainland, ten times as many as compared to North America. And, strangely, the Sardinian men live as long as the women. (In contrast to the rest of the industrialized world, where women live on average seven years longer than men.) Susan Pinker, author of The Village Effect, visited this region to see what made it unique. “Architectural beauty is not its main virtue; density is. Tightly spaced houses, interwoven alleys and streets, it means that the villagers’ lives constantly intersect,” wrote Pinker. “Wherever I went to interview these centenarians I found a kitchen party. I quickly discovered by being there in this ‘blue zone’ that as people age, and across their life-spans, they are always surrounded—by extended family, by friends, by neighbors, the priest, the barkeeper, the grocer. People are always there or dropping by; they are never left to live solitary lives.”
Perhaps the best way to close this section is by looking at the person with the longest life-span recently recorded: Jeanne Louise Calment, of France. Calment was born in 1875, three years before Halsted arrived in Vienna for his European tour, and a year before Alexander Graham Bell patented the telephone. She died in 1997 at the age of 122. One might imagine that to live that long—far longer than most gerontologists thought was even possible—Calment must have had “perfect” genetics coupled to a “perfect” lifestyle. Yet nothing about her family could predict Calment’s extreme longevity. Members of her immediate family did live longer than average, but not extraordinarily so: Her brother lived to the age of 97, her father lived to 93, and her mother to 86.
At the age of 21 Calment married her second cousin, a wealthy shop owner, and consequently Calment never had to work. She and her husband lived a life of active leisure. She enjoyed fencing, mountaineering, bicycling, roller-skating, playing the piano, painting, attending the opera, tennis, swimming, and even tagged along on her husband’s hunting parties. “I had fun; I am having fun,” said Calment, looking back on her life. Calment’s husband introduced her to smoking after dinner when she was twenty-one. She smoked one or two cigarettes a day until she was 117. She enjoyed port wine, of which she usually had a glass or two per day. And she also enjoyed sweets, especially chocolate, of which she reportedly ate two pounds per week. According to those who knew Calment, her most distinguishing feature seemed to have been her steadiness. She never appeared stressed about anything. “I think she was someone who, constitutionally and biologically speaking, was immune to stress,” said a friend. “If you can’t do anything about it, don’t worry about it,” she once quipped. When Calment turned 100 she rode her bike from house to house in her hometown of Arles, France, to thank everyone who had congratulated her on her birthday. She reluctantly entered a nursing home at the age of 110. Calment claimed she didn’t care for socializing much. “I didn’t enjoy visiting, I didn’t like the fashionable world, but I loved being out in the fresh air.” But those observing her in the nursing home suggested otherwise. There she befriended one of the nurses who smoked a French brand of cigarette that was dark and particularly strong. She reportedly switched to the nurse’s brand and often joined her new friend in the evening for a smoke. One evening Calment fell on the stairs going up to the nurse’s room and broke her hip. After undergoing an operation to repair her hip she was warned that, due to her age, she might not be able to walk again. “I’ll wait, I’ve got plenty of time,” she replied. Within a few days she was able to get out of bed and even stand. However, the injury left her mostly dependent on a wheelchair. Most days, after an afternoon nap, Calment enjoyed going to other rooms and talking with the other residents about the current events she had learned about that day. She remained witty to the end, often sparring and joking with the reporters who interviewed her. “I’ve never had but one wrinkle, and I’m sitting on it,” she liked to joke. In every article I could find about Calment, I couldn’t find one where she confessed to being lonely. Although it seems she didn’t have a voracious requirement for social connections, she had more than enough throughout her life. She expressed mostly gratitude for her long life. At the age of 120 she said, “I dream, I think, I go over my life. I never get bored.”
All told, there is certainly nothing remarkable about Calment’s lifestyle. She smoked sparingly, drank a little bit, enjoyed good food, and ate desserts. She didn’t worry much. She was active and social, never professing to feeling lonely. Perhaps the way she lived her life is a good lesson for us all. Her life reflects the science behind longevity. Genetics, clean air, exercise, diet, and avoiding bad habits do matter, but perhaps not to the extent that many of us believe. What matters the most is being connected, fulfilled, and engaged in the world. It’s beautiful, in a way, that the science of health and longevity also serves as a guidepost for a rich and meaningful life. Don’t worry so much. Have an occasional dessert or drink if you want to. Be active. Play. Be moderate. Engage with the world and the people around you. Not only will you live longer, but you will live better. ?
—Well Being Journal adapted this article from Curable: How an Unlikely Group of Radical Innovators Is Trying to Transform Our Health Care System copyright 2019 by Travis Christofferson, MS, used with permission from Chelsea Green Publishing, White River Junction, Vermont, 802-295-6300; www.chelseagreen.com. Referenced and indexed.
Travis Christofferson, MS is the author of Tripping Over the Truth, a full-time science writer, and founder of a cancer charity. He lives in South Dakota.